hydroponics for begginers

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Hydroponics Growing Systems

Each of the hydroponics growing systems has its own way of supporting the plants. Plants require food, water, and oxygen for the roots to keep them from drowning. You can scroll down the page to see how each system works one by one, or you can use this menu to jump to any system. The main types of hydroponics growing systems are the...

Hand Watering

People often do not realize that hand watering can be one of the simplest hydroponics growing systems, but hydroponics boils down to this...the food is in the water.

If you mix perlite, vermiculite, and coconut coir (all nutrient free) and use this to grow your plants in a container garden, you will HAVE TO include some plant food in the water when you hand water.

By deffinition, this is an example of hydroponics gardening. A 50/50 mix of perlite/vermiculite would work just as well.

Coconut coir and vermiculite retain quite a bit of water. By using more of them in the soiless mix, the containers will stay moist between hand-waterings (every day or two). Sphagnam peat is the base of many commercial potting soils and can be used as a substitute for this purpose also.

Because of its simplicity, this is obviously an easy home method. This is one of the hydroponics growing systems that will easily support organics. No matter what type of system you choose, you will need to learn some hydroponics feeding tips.

The Reservoir Method

The reservoir method is one of the easiest of all the true hydroponics growing systems. A container holds about two inches of nutrient solution. Several plant containers sit down in the nutrient solution. An aquarium air pump constantly bubbles in the nutrient solution, keeping the plants roots from drowning.

Often, small holes are made around the bottom 2 inches of the plant pots, allowing the roots to grow out into the nutrient solution.

As in the example above, an effort is usually made to keep light from getting to the nutrient solution.

Wherever there is light and nutrients, algae will grow. Algae eat the nutrients you are trying to feed to your plants, and when pieces of algae die they attract fungus gnats. Fungus gnats lead to many other problems.

Because of its simple design and simple function, the reservoir method is a good choice for homemade hydroponics. Since there are no drip or spray emitters to clog, it is also a good choice for organic hydroponics growing systems.

This system is well suited for volcanic lava chips media, or else a mixture of one part vermiculite to 5 parts expanded clay pellets.

As with any hydroponics growing system, you will want to brush up on your hydroponics feeding tips before beginning.

The Flood and Drain Method
aka Ebb and Flow

Of all the hydroponics growing systems, this is the system I use most often myself.

In the flood and drain method, the plants sit in their own container separate from the nutrient reservoir.

From time to time, a pump will kick on. The nutrient solution from the reservoir floods the upper container for a while, soaking the plant roots and the grow medium. The pumps than turn off, and the solution drains back into the reservoir.

Your choice of grow media determines how often and how long you flood the container for. Fast draining, clay pellets may be flooded for a half hour 4 times a day, while the slower draining rockwool can be watered less.

This system is also well suited for growing in straight perlite or lava chips.

The parts and function of this hydroponics growing system are pretty basic, making it another good option for a homemade hydroponics system. With a good water pump, you can also use this method for organic hydroponics. It is always a good idea to have a filter before the pump in any system.

Of course, you will make any hydroponics growing system work its best with the right hydroponics feeding tips.

The Drip System

With the drip hydroponics growing system, the plants are again in their own tray, separate from the nutrient reservoir. A pump pushes nutrient solution through many small tubes, which feed each plant from the top. Different emitters can be placed on the end of each tube to make the drip slower or faster.

Once again, a faster draining medium (like clay pellets) will need faster dripping emitters (or more of them per plant). Slower draining media (like rockwool) would use slower dripping emitters.

The standard media for drip systems is rockwool, although clay pellets and lava chips are also sometimes used. Straight perlite should work well in this system also, although I've never tried it myself.

The flow rate is difficult to control on a drip system, and the emitters are famous for clogging. These problems are even worse when you try to make your own drip system. You will probably spend a lot of money and have a poorly working system if you try to build a homemade drip system (I know this from personal experience).

Furthermore, organic nutrients are full of small particles that ALWAYS seem to mess up the drip emitter. If you are trying to do organic hydroponics, this is not the system for you.

The Nutrient Film Technique


In this hydroponics growing system, plants are placed in a tray or gutter separate from the nutrient reservoir. One end of the tray is lower than the other, to encourage the flow of water.

A pump delivers a steady flow of water at one end, creating a constant stream of nutrient solution in the bottom of the tray. In order to make sure the water flowing through the bottom of the tray is nice and even, a layer of absorbant material (called capillary matt) is placed in the bottom.

NFT is another method that is both easy for the homemade hydroponics do-it-yourselfer and also a good choice for organic hydroponics growing systems. Once again the parts, the design, and the function are all simple. once again, there are no drip or spray emitters to clog.

There is one thing to consider, however. You must start with plants that have a root system large enough to hang down into the flowing nutrient solution. Your other option would be to top feed the plants with a drip system until their roots are large enough (which is a pain).

It doesn't matter what type of media you start your plants in. Once they are in place in the system, the roots will be growing right in the water!

This system, when the proper hydroponics feeding tips are followed, works very nicely.

The Wick System

In wick hydroponic growing systems, the plants are again in their own container, separate from the nutrient reservoir. Pieces of absorbant material (usually nylon rope) are buried partially in each plant container. The other end of the rope is allowed to dangle in the nutrient solution.

The absorbant material pulls the nutrient solution from the reservoir up into the growing medium.

The system is easy to make as a homemade hydroponics system, and will support organic hydroponics without any problems, but there are a coulple of things to consider.

Sometimes it is difficult to get the right moisture level in a wick system. You will have to experiment a little with more absorbant growing mediums (vermiculite/coconut coir). Also, I have seen the wicks suck up less and less water over time (especially when using organics).

If you want to give this method a try, I suggest a 50/50 mix of perlite/vermiculite. Perlite and coconut coir would work as well.

Altogether, I think other systems are just as easy to use, and produce better results.

The Aeroponics Method

In these hydroponics growing systems, a large container like this contains several gallons of nutrient solution in the bottom. A pump pushes nutrient solution through spray heads that constantly soak every inch inside the container with a fine mist of nutrient solution.

As you can see, there really is no growing medium in this method. The plants roots hang down into the container and grow mostly in air, except for the few that grow long enough to make it into the nutrient solution in the bottom.

The pump used is a high-pressure pump, and the spray emitters are made specially to deliver a very fine, highly oxygenated spray.

It is often very hard to assemble individual parts into a well-working system, and the individual parts can be expensive as well. Also, the fine-spray emitters will instantly clog if you try to use anything except high quality hydroponic fertilizers (no organics).

Of all the hydroponics growing systems, this is the most difficult to master and the most tempermental. Ph changes and nutrient imbalances occur more quickly because of the increased absorbtion rates and high levels of oxygenation.

Furthermore, with no grow media to protect the roots, the plants react negatively to these changes much more quickly.

More recently, some innovative gardeners have begun to push this new area. Systems are beginning to pop up that are much simpler and that do not rely on pumps. Aeroponics does offer faster growth rates, which continue to drive the demand for it.

here,s a good link to show you the flood and drain and the dripper system too

pH / EC / TDS / PPM

What are the pros and cons of buying a combo meter?

The combination type meters are real handy for the convenience of being able to take both readings simultaneously, or with a single touch of a button to switch between modes. The problem IMHO with combination meters is pH sensors like to be stored in a fertilizer solution, but TDS probes like to be stored in distilled water. Storing the pH probe in plain or distilled water will damage the ph membrane, so the combination probe needs to be stored in a fertilizer solution so as not to damage the pH portion, so the TDS probe ends up being "dirty" from salt buildup. A friend has already lost one expensive probe on his Hanna from this same problem, and will only purchase "single function" pH or TDS meters in the future.

What is the difference between ppm and EC?

Total Dissolved Solids (TDS) is the best measurement of the nutrient concentration of a hydroponic solution. To estimate TDS, one can use a meter that measures the Electric Conductivity (EC) of a solution, and convert the number to TDS in parts per million (ppm). Many meters will do this conversion.

Total dissolved solids (TDS) is typically expressed in parts per million (ppm). It is a measurement of mass and determined by weighing, called a gravimetric analysis. A solution of nutrients dissolved in water at a strength of 700 ppm means that there are 700 milligrams if dissolved solids present for every liter of water. To accurately calculate total dissolved solids (TDS), one would evaporate a measured filtered sample to dryness, and weigh the residue. This type of measurement requires accurate liquid measurement, glassware, a drying oven, and a milligram balance. Example: 50 mL of the 700ppm solution would leave 35 mg of salt at the bottom of a crucible after drying.

Electrical Conductivity (EC) is expressed in siemens per centimeter (s/cm) or milliseimens per centimeter(ms/cm). It can be determined with an inexpensive hand held meter. Nutrient ions have an electrical charge, a whole number, usually a positive or negative 1, 2, or 3. EC is a measurement of all those charges in the solution that conduct electricity. The greater the quantity of nutrient ions in a solution, the more electricity that will be conducted by that solution. A material has a conductance of one siemens if one ampere of electric current can pass through it per volt of electric potential. It is the reciprocal of the ohm, the standard unit of electrical resistance. A siemens is also called a mho (ohm backwards).

For convenience, EC measurements often are converted to TDS units (ppm) by the meter.

The meter cannot directly measure TDS as described above, and instead uses a linear conversion factor to calculate it. Everyone’s nutrient mix is different, so no factor will be exact. The meter uses an approximate conversion factor, because the exact composition of the mix is not known. Conversion factors range from .50 to .72, *depending on the meter manufacturer, which do a good job of approximating a TDS calculation from the meter’s measurement of EC.

* All ppm pens actually measure the value based on EC and then convert the EC value to display the ppm value, having different conversion factors between differing manufacturers is why we have this problem communicating nutrient measurments between one another.

EC is measured in millisiemens per centimeter (ms/cm) or microsiemens per centimeter (us/cm).

One millisiemen = 1000 microsiemens.

EC and CF (Conductivity Factor) are easily converted between each other.

1 ms/cm = 10 CF

"The communication problem"...

So again, the problem is that different ppm pen manufacturers use different conversion factors to calculate the ppm they display. All ppm (TDS, Total Dissolved Solids) pens actually measure in EC or CF and run a conversion program to display the reading in ppm's.

There are three conversion factors which various manufacturers use for displaying ppm's...

USA 1 ms/cm (EC 1.0 or CF 10) = 500 ppm

European 1 ms/cm (EC 1.0 or CF 10) = 640 ppm

Australian 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

For example,

Hanna, Milwaukee 1 ms/cm (EC 1.0 or CF 10) = 500 ppm

Eutech 1 ms/cm (EC 1.0 or CF 10) = 640 ppm

Truncheon 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

Calculating the conversion factor

If your meter allows you to switch between EC and TDS units, your conversion factor can be easily determined by dividing one by the other.

Place the probe in the solution and read TDS in ppm. Change to EC on the meter and read EC in ms/cm.

Conversion factor = ppm / ec.

[Note: ms must be converted to us: One millisiemen = 1000 microsiemens (1.0 ms/cm = 1000.0 us/cm)

According to the chart below:

1.0 ms/cm = 500 ppm (USA Hanna)

1000 us/cm = 500 ppm

Conversion factor = ppm / (ms/cm * 1000)

.50 = 500ppm / (1000us/cm) ]

The answer is your meter's convertion factor and should be a number between 0.50 and 0.72 To improve accuracy, take ec and ppm readings from your res daily for about ten days. Average the conversion factors. The more data points that you use, the closer you will be to finding your true conversion factor.

When reporting your PPM in a thread, please give the conversion factor your meter uses. For example: 550 PPM @0.7 or give the reading in EC, which should be the same meter to meter.

It may also be advisable to give the starting value of your water; there is a huge difference between RO and distilled water with a PPM of approximately 0 and hard tap water of PPM 300 @.5 (notice the conversion factor so others can work out the EC) or well water with a conductance of 2.1 ms/cm.

A note to Organic Growers:

An EC meter has fewer applications for a soil grower because many organic nutrients are not electrically charged or are inert. Things like Superthrive or Fish Emulsion, blood meal, rock phosphate or green sand cannot be measured with a meter reliably when they are applied or in runoff. Meters can only measure electrically charged salts in solution.

"The solution"...

When reporting your PPM in a thread please give the conversion factor your meter uses for example 550 PPM @.7 or give the reading in EC (the EC shoul d be the same meter to meter).

EC Hanna Eutech Truncheon CF

ms/cm 0.5 ppm 0.64 ppm 0.70 ppm 0

0.1 50 ppm 64 ppm 70 ppm 1

0.2 100 ppm 128 ppm 140 ppm 2

0.3 150 ppm 192 ppm 210 ppm 3

0.4 200 ppm 256 ppm 280 ppm 4

0.5 250 ppm 320 ppm 350 ppm 5

0.6 300 ppm 384 ppm 420 ppm 6

0.7 350 ppm 448 ppm 490 ppm 7

0.8 400 ppm 512 ppm 560 ppm 8

0.9 450 ppm 576 ppm 630 ppm 9

1.0 500 ppm 640 ppm 700 ppm 10

1.1 550 ppm 704 ppm 770 ppm 11

1.2 600 ppm 768 ppm 840 ppm 12

1.3 650 ppm 832 ppm 910 ppm 13

1.4 700 ppm 896 ppm 980 ppm 14

1.5 750 ppm 960 ppm 1050 ppm 15

1.6 800 ppm 1024 ppm 1120 ppm 16

1.7 850 ppm 1088 ppm 1190 ppm 17

1.8 900 ppm 1152 ppm 1260 ppm 18

1.9 950 ppm 1216 ppm 1330 ppm 19

2.0 1000 ppm 1280 ppm 1400 ppm 20

2.1 1050 ppm 1334 ppm 1470 ppm 21

2.2 1100 ppm 1408 ppm 1540 ppm 22

2.3 1150 ppm 1472 ppm 1610 ppm 23

2.4 1200 ppm 1536 ppm 1680 ppm 24

2.5 1250 ppm 1600 ppm 1750 ppm 25

2.6 1300 ppm 1664 ppm 1820 ppm 26

2.7 1350 ppm 1728 ppm 1890 ppm 27

2.8 1400 ppm 1792 ppm 1960 ppm 28

2.9 1450 ppm 1856 ppm 2030 ppm 29

3.0 1500 ppm 1920 ppm 2100 ppm 30

3.1 1550 ppm 1984 ppm 2170 ppm 31

3.2 1600 ppm 2048 ppm 2240 ppm 32

How do I tell if my PPM/EC is too high or too low?

It's simple to find out if you are using too much food or not enough by watching the nutrient concentration levels in your tanks day to day. Don't be concerned with the exact reading, rather watch how it rises and falls from each day to the next. The differences between when you put the solution into the tank and the readings you get several hours later or the next day are what tell you if your plant is eating, drinking or happy.

Start with 1.00 EC (or a SAFE nutrient strength). Next day, if it reads 1.4, it means your plants have been using water and your nutrient solution is becoming more concentrated. This means the concentration of nutrients is too high, so you dilute.

If the meter reads lower than the previous day, 0.7 say, it tells you that the plants are eating nutrients faster than they are drinking water, so you should increase your nutrient strength. If it remains the same, your feeding schedule is on target for now. The nutrient/water intake fluctuates with the growth of the plant, so you must continually monitor it day to day.

Your plants will tell you the optimum nutrient levels. When they are receiving optimum food and water, the readings remain constant. The more you do it, the easier it gets. The reason no one can tell you what PPM/EC levels to use is because every garden is different and every plant has different requirements due to their particular environment. That's why you have a ball park starting figure, but after that your plants will tell you almost exactly what they require.

What is a good ph/EC/TDS meter?

I use and recommend the Hanna HI9813 Grocheck portable ph, ppm and EC meter. It is available from most larger indoor garden supply retailers for around $200. I have had one for several years and it never drifts more than .2 on the ph scale or 30ppm from the original calibration made. I keep the electrode immersed in Hanna storage solution and use a hand held trigger sprayer to clean the film and residue that accumulates on it. I feel this contributes to my consistent readings without any need for re-calibration at al:

I've had the lower model waterproof Oakton pens for over 5 years with no problems. I've replaced the pH probe twice since I let it dry out too long, but I did that for piece of mind and not because it really needed it.

Are the liquid type Ph test kits accurate?

Liquid Ph test kits offer the grower an inexpensive alternative to the expensive test meters and give results which are accurate enough to accomplish the task just fine. Usually reading within +/- two tenths of a point (.02) of electronic meters, depending on the kit.

For the grower looking for the most accurate Ph control, there are many various electronic Ph testers available that when calibrated will give extremely accurate readings. Unfortunately for quality units, you may be looking at a higher price than you are able to pay, even the best units will suffer down time as probes go bad. Ph probes are especially prone to failure as the membrane ages, eventually drying out and failing.

The most common solution to fill the void is liquid type Ph test kit.

They're quick, reasonably accurate and very inexpensive.

Great backup in case your probe fails.

When using liquid Ph testers, there are some important things to keep in mind:

Always use a white background when looking at the color in the vial.

A non white back ground can alter the color subtly enough that you may end up being off by anywhere from a little to a lot depending on the color background being used.

Make sure that all color comparisons are done under natural light or normal household lighting and NOT HID light, as the red/blue spectrums of the light (HPS and MH respectively) will cause serious variations to the appearance of the solution, and in some cases you could be running your solution as much as a whole point above or below what it should be.

What ranges should I maintain for my hydroponic nutrients pH, TDS/EC and temperature?

I follow and highly recommend the following parameters for hydroponic nutrient solutions for aeroponic, “bubblers”, drip, ebb and flow, NFT, passive, rockwool and wick systems.

PH 5.1-5.9 (5.2 optimal)

TDS 500-1000ppm, EC .75-1.5

Temperature 68-78f, 20-25c (75f, 24c optimal)

The pH of the nutrient solution is a major determinant of nutrient uptake by the plant. If the pH wanders outside the optimum range of between pH 5.1 and pH 5.9, then nutritional deficiency and/or toxicity problems can occur. For hydroponic nutrient solutions used with inert media, keep the pH at 5.2 for optimal elemental uptake. It is at this point that roots most readily assimilate nutrients. These pH and TDS/EC recommendations may seem low relative to the normally suggested range, but are based upon information garnered from "Hydroponic Nutrients" by M. Edward Muckle and Practical Hydroponics and Greenhouses. They both document the low pH resulting in increased nutrient uptake and my experience has shown discernible health and yield improvements at a ph of 5.2 over higher levels.

On page 100, Hydroponic Nutrients displays both the assimilation chart for organic soil applications and another for inert medium hydroponics, which depicts the vastly different scenarios. The widely accepted soil based chart is frequently misapplied to water culture applications. His research and that done by others, documented in Practical Hydroponics and Greenhouses, indicate that iron and phosphorous precipitate in nutrient solutions at pH levels above 6. Stay below a pH of 6 by all means to avoid this problem and benefit.

The nutrient assimilation rate is further enhanced by the reduction in solution TDS/EC, which reduces osmotic pressure and allows the roots to draw the nutrients "easier". Young, established seedlings or rooted cuttings are started at 500-600ppm. The TDS is increased to 800-900ppm during peak vegetative growth. During the transition from early to heavy flowering, TDS is further raised to 1000-1100ppm. It is then reduced to 400-500ppm during the final 2 weeks of flushing. The plants demonstrate their preference for a lower TDS/EC when running a lower pH by clearly sustaining higher growth rates.

The optimum temperature for hydroponic solutions to be is 24c/75f. At this point, most elements are assimilated highest and atmospheric oxygen is most readily dissolved. Although increases in temperature increase the rate of photosynthesis, avoid exceeding the maximum listed of 25c/78f. Elevated temperatures make some elements more available, but reduce the solution's dissolved oxygen capacity, increasing root disease likelihood.

What is pH?

The pH scale measures how acidic, or how alkali a given solution is.

The term pH can be broken down into two parts; the first is the [p], this represents the mathematical symbol for -log (negative logarithm) of the number in question. The “H” stands for Hydrogen, and is represented by the chemical symbol [H] So the correct way to write this down is a small p, and a capital H (pH).

The pH scale is basically a rough guide as to how many Hydrogen ions are present in any given substance; the more hydrogen ions are present, the more acidic the substance becomes. The pH of distilled water is 7.0, this is neutral. Any solution with a pH below 7.0 (i.e. pH 1.0 to pH 6.9) is an acid and any solution with a pH above 7 (i.e. pH 7.1 to pH 14) is an alkali. The pH scale is logrithmic, that is, a pH 6.0 solution is 10 times more acidic than a pH 7.0 solution (pH 5.0 is 100x more than 7.0!).

Acidic solutions have a pH between 1 and 6.9 (your stomach contains HCl it is pH2).

Alkaline solutions have a pH between 7.1 and 14. (your small intestine is pH 9).

Neutral solutions are neither acidic nor alkaline so their pH is 7.

Acids all produce Hydrogen ions (H+). Acids like Hydrochloric acid produce lots of Hydrogen ions; this is because when Hydrogen Chloride gas dissolves in water the molecules of Hydrogen Chloride dissociate into Hydrogen ions and Chloride ions.

HCl = H+ + Cl-

Water also dissociates to produce ions, this time it is Hydrogen ions and Hydroxyl ions.

H2O = H+ + OH-

Sodium Hydroxide also dissociates to produce ions when it is dissolved in water, this time it is Sodium ions and Hydroxyl ions.

NaOH = Na+ + OH-

In each case, we can measure or calculate the concentration of Hydrogen ions present. We use the symbol [H+], we use square brackets to mean that it is the concentration of Hydrogen ions.

In HCl Hydrogen Chloride solution or Hydrochloric acid [H+] = 0.01

In H2O water [H+] = 0.0000001

In NaOH Sodium Hydroxide solution [H+] = 0.00000000000001

We count the decimal places from the first number, and that is where the pH scale is derived from.

HCl = pH2

H2O = pH7

NaOH = pH14

So to recap if the pH is low, it means that there is a high concentration of Hydrogen ions and if the pH is high it means that there is very low concentration of Hydrogen ions or none at all. Water and other neutral solutions are in the middle at pH7.

What is a pH buffer?

Chemical equilibrium

To more deeply understand pH, we must first explore the concept of chemical equilibrium. The pH of pure water is considered neutral, because this is the point at which the autoprotolysis of water is just as favorable of a process as the reverse reaction. The chemical equation for the autoprotolysis of water is as follows:

H2O <---> H+ + OH-

The equilibrium constant for this reaction is called Kw, which is equal to the product of the concentrations of hydrogen ion and hydroxide ion in solution in moles per liter (See Appendix 1 below to calculate the #moles/L)

The dissociation constant

Kw = [H+][OH-]

At this point, it is valuable to understand the p function itself. The p function of some value is equal to the negative logarithm of that value. So,

pH = -log[H+]

pKa = -log(Ka)

The value for Kw is 0.00000000000001 at 24°C, which is easier to write as pKw = 14. So, for pure water, we know that all H+ and OH- came from water molecules, and thus they are equal in number throughout the solution. Since they have the same value, we can use the above equilibrium expression as follows:

Kw = [H+][OH-] = [H+]2 = 10-14

Thus, [H+] = 10-7, and pH = 7.

Acids and Bases

Any chemical that increases the concentration of hydrogen ion in solution, or lowers the pH is an acid. Likewise, any chemical that increases the hydroxide concentration in solution is a base.

When an acid and its conjugate base are present in solution together, that solution is said to be a buffer, since it may react with acid or base without significant changes in pH. A hydroponic nutrient solution contains several conjugate acid-base pairs, since there are so many species present.

For a solution containing an acid HA and its conjugate base A-, the following equilibrium exists:

HA + H20 <---> H3O+ + A-

For this protolysis equilibrium, the acid dissociation constant is given by:

Ka = [H3O+]*[A-]/[HA]

The pH is given by the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

The term pKa refers to the p-function of the dissociation constant for that acid in water, similar to pKw for water. Notice from the equation above that as long as the acid and conjugate base are within one order of magnitude in concentration, additions of acid or base will not greatly affect the pH.


The buffering capacity, or ability to resist change in pH, is greatest within one pH unit of the pKa for the acid. A complex equilibrium exists between the concentrations of all of the species present in the nutrient solution and the concentration of available hydrogen ions, making the nutrient solution a buffer over a very large range. This is why adding acid to pure water decreases the pH much faster than adding acid to the mixed nutrient solution.

Any species added to solution that can be either a proton donor (acid), or a proton acceptor (base), sets up a buffer.


You may have found that pure water you leave out in the air becomes slightly acidic over time. This is due to the absorption of CO2 from the atmosphere. The chemical process is as follows:

CO2 + H2O ---> H2CO3 <---> H+ + HCO3-

Carbon dioxide reacts with water to form carbonic acid, which dissociates in water to hydronium and bicarbonate anion. This increases the concentration of H+ in solution, reducing the pH. The pKa of carbonic acid is 6.4, which is about the pH of pure water that has been exposed to the air.

ex) Potassium bicarbonate

Potassium is K+, bicarb is HCO3-. usually with diprotic acids like carbonic and sulfuric, the first H comes off pretty easily but since the ion has a -2 charge it holds onto the second proton fairly strongly.

Potassium bicarbonate is KHCO3, which dissociates to K+ and HCO3-. The bicarbonate anion can act as either an acid or a base. This makes it amphoteric.


In chemical fertilization, EDTA salts are used as “chelators”. The purpose is to form a more stable species in solution by using bidentate bonds. This means that the metal ion (such as Mg2+) will have two bonds for each EDTA molecule attached. This entropy of formation is higher for the EDTA complex, preventing the metal ions that you want to stay in solution from reacting to form insoluble compounds. Chelation makes the nutrient species more soluble, and thus more readily available for uptake.

What effect does pH have on elements in solution?

The element of interest to the plant must be present in an ionic form that can be transported by the roots. Changes in pH mean changes in concentration of H+ and OH-, which drive changes in equilibrium between various salt forms. For example... if the pH is too high, any available OH- will react with manganese or magnesium, or any of the various components of the nutrient solution.

Mg2+ + 2 OH- ---> Mg(OH)2

Magnesium hydroxide is not available for passive transport into the root system, but Mg2+ is. On a similar note, contamination by chlorine is bad for your solution, because MgCl2 is insoluble as well, and has a high rate constant of formation.


1. Calculating Molar concentration

The molar concentration of a substance in solution is calculated by converting the mass of the substance into moles, and dividing that number by the liters of solution.

To make the conversion, you add up the atomic masses (from the periodic table of elements) for each atom in a single molecule of that substance. This is the molar mass. Divide the mass of the substance added to solution by the molar mass. This result is the number of moles. Divide this by the volume to get the molar concentration.

Let's do an example:

We add 2.5g Epsom salts to 2 liters of water. The chemical formula for Epsom salt is MgSO4·7H2O.

The atomic masses are as follows:

Mg = 24.3 g/mol

S = 32.1 g/mol

O = 16.0

H = 1.01

Now remember to multiply each mass by the number of that species present in the molecule.

Total mass = 24.3 + 32.1 + (11*16.0) + (14*1.01) = 246.5 g/mol.

Now we convert grams to moles: 2.5g / 246.5 g/mol = 0.0101 mol.

Since we used two liters, we divide number of moles by 2, and the result, [MgSO4·7H2O] = [Mg+] = [sO4-] = 0.00507 mol/L = 0.00507 M.

Note: since Epsom salt is an ionic species, it dissociates in solution.

How long does the seal last inside the probe?

Something to note for all pH meters is the age of the meter; the gel seal inside the meter is only usually guaranteed to keep its seal for 2 years after being manufactured, although the gel seal may last much longer this.

Digital meters such as the pHscan 1 have the month and year of manufacture on the inside of the battery lid. I suggest checking it when purchasing as some hydro stores may have slow stock turnover.

What does pH mean?

The degree of acidity/alkalinity of a solution is identified on the ph scale of 0 to 14, with a pH of 7 representing the neutral point. The pH scale is logarithmic, meaning small changes in pH represent large changes in the degree of acidity or alkalinity. For example, a solution with a pH of 5 is ten times as acidic as a solution with a pH of 6, but a solution with a pH of 5 is 100 times as acidic as a solution with a pH of 7. The pH of the nutrient solution is a major determinant of nutrient uptake by the plant.

What is a TDS meter and what does it measure?

Total Dissolved Salts meters are essentially little voltmeters that look at the voltage produced by a sensor, usually a couple of metal pins. The nute solution acts like a battery electrolyte and the pins function as do plates (electrodes) in a battery. The idea is that a nutrient solution is more electrically conductive when there are more nutrient salts in solution, so more salts means more voltage. A little math is done in the machine to convert the voltage to ppm (parts per million of dissolved solids).

There is a calibration adjustment so this math can be touched up to compensate for various factors. You will need a test solution to verify your meter once a week. Usually you will find a single measurement at about 1500-1700ppm is enough to verify it's reading what it's supposed to.

You need one that will read at least 0-2000ppm (or 0-1999ppm). You could use a 0-999ppm meter in a pinch if you added an equal volume of plain water to a sample from your tank-- you'd just double the meter reading.

It's best to simply get the correct meter.

There are other scales of measurement of nutrient concentration. In Europe, the "EC" (electrical conductivity) meters are preferred. They measure in units of millisiemens or mS instead of parts per million (ppm). The numbers are convertible one scale to the other, but most references and discussion here cite the ppm scale.

Waterproof meters are both more expensive and worth it.

How do I figure out the ppm of my fertilizer mix?

To figure out the ppm of your fertilizer (or fertilizer mix), you need to be able to measure grams and liters. Look at the 3 numbers on the side of a fert bag. These are the percent content of the nutrients. For every one gram of said fertilizer in one liter of water, it contributes 10 ppm of the given nutrient per percentage point. A 20-20-20 gives 200 ppm (10 ppm X 20) of each nutrient for each gram in a liter of water.

The formula is this:

grams of fert per liter = A/B

A=your desired ppm

B=10 ppm X the % of nutrient in mix


your ppm = C X B

B=10 ppm X the % of nutrient in mix

C= grams of fert per liter

So to make a 200 ppm-100 ppm-200 ppm NPK mix using a 13-0-44 (potassium nitrate), a 12-62-0 (monoamonium phosphate), and a 33-0-0 (ammonium nitrate) you would work backwards from your sole P and K sources (it makes it easiest in this case), and make up the N at the end. I have rounded numbers to the nearest 0.1 g for the following. You would use 0.5 g of potassium nitrate (200 ppm/(10 ppm X 44 K)) and 0.2 g of monoammonium phosphate (100 ppm/(10 ppm X 62 P)) in one liter. This would give you 89 ppm N (10 ppm X 13 N X 0.5 g + 10 ppm X 12 N X 0.2 g), 124 ppm P (10 ppm X 62 P X 0.2), and 220 ppm K (10 ppm X 44 K X 0.5 g). 111 ppm are needed to raise the N to the 200 ppm level, so we can use 0.3 g of the ammonium nitrate (111 ppm/(10 ppm X 33 N)) to bring us up to finish.

The actual mix would yield a 188 ppm N, 124 ppm P, 220 ppm K mixture in one liter of water. To get more precision, you need to mix larger batches or get a better scale (you would need to make a 10 liter batch of the above with a scale that is only accurate to the gram).

If you mix your own fertilizer, you can adjust your N source to meet your pH needs, rather than being dependent on adding acid or base, which is nice.

This works for formulating hydro mixes, as well as for us dirt farmers


hi all if this info is liked i will ad more later let me no what u think

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Cool it would be nicer with pics included inside to aerate a little the block lol ^^

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Hey Buddy. That is a nice work and collection of informations. Iam personally using TDM and convert this to ec. But buddy, the conversion chart is missing PPM500/TDS itself. The Truncheon is known as PPM700.

millisiemens per cm2
ppm 500/ TDS
ppm 700

* source:

TDM/PPM meter from TDS

Thanks alot for your FAQ. I appreciate that very.

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thanks buddy any other info people can ad charts etc please ad it all helps, i know how anoying it was when i first started and could,nt find everything the more info the better and thanks again bud for adding chart

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What are light cycles and how do I use them?

The amount of time your garden should be exposed to lighting depends on what 'cycle' your garden is in:


'Vegetative Cycle'

of your garden starts with the sprout of the seedlings and can be continued indefinitely. In the veg cycle your garden will require a minimum of 16-18 hours of light and 6-8 hours of darkness daily. Since a given amount of light can only do so much, equal production can be realized in a smaller space with less plants, where the light is concentrated and the plants can grow more efficiently. Using more light helps additional co2 uptake.

Since a plant can be kept in the 'Veg cycle' indefinately, many growers cultivate 'Mother' plants. This plant is used for clone starts and never produces buds, only new growth.


'Flower Cycle'

or 'Bud cycle' is typically equal amounts of light and dark, 12 hours on, 12 hours off or 12/12. This produces a change in the plants metabolism simulating Fall, shorter days....less light.

This is the cycle that the plants will show their sex. Usually, you'll be able to determine the sex within the first 2 weeks of 12/12. By the 3rd week most plants have developed healthy bud sites or pollen sacks.

The plants will continue on the 12/12 cycle until harvest.

When someone 'Re-vegges' a plant that has been in the flower cycle, they're switching the light cycle back to 18/6 to stimulate new vegetative growth.

What distance should my light be from my plants?

For (artificial) light, there is a law that always applies known as the Inverse Square Law. It states that light diminishes exponentially in energy as the distance is increased from the source.

A good example is that you might be getting 1000 PAR Watts at 4" from your light source, but that would change to 250 PAR Watts at double the distance (8"). This law makes it EXTREMELY important for indoor plant growers to get their light source as close as possible to their plants. The amount of light your plant receives is directly related to it's yield/flower density.

The problem: Indoor lamps used for plant cultivation (HID - High Intensity Discharge) give off large amounts of heat, to such a degree that they could cause damage to the plant if put too close.

Indoors, there is an optimum distance/height between the plants and the light source. This distance fully illuminates the whole canopy with direct light from the source, but is as close as possible to the plants for maximum lumen intensity. This will be called the OLH, for Optimum Lamp Height.

Ultimately, to get the best light efficiency from your lamp, you want it at the OLH at all costs. But how can you get it there without causing harm to your plants with the abundant heat?

First, try moving your light to the OLH and see what it does to your plants. If they have no problem, then you're fine. If you have a high output HID, this probably won't be enough.

Next, try actively exhausting your light hood by hooking up a direct exhaust system to the hood, and then move your lamp to the OLH and see if the plants are O.K. If the plants still seemed affected by the heat, then you must add glass to your actively exhausted lamp hood. Glass will absorb/reflect/filter some of the light energy being emitted by the lamp.

The number would seem relatively low, around 2-3% of PAR wattage, but it will effectively filter out almost all of what little UV-B is emmitted by the lamp. UV-B is believed, and has been shown, to have a positive influence on the potency of Cannabis.

Overall, it would be beneficial for one to add glass if needed to keep their lamp at the OLH, due to the all-powerful Inverse Square Law; moving light farther away will greatly reduce the amount of energy being emitted and is reaching your plants (Light intensity is directly related to yield and flower density).

Almost all glass offered today for insertion in air-cooled lamp hoods is tempered glass, which is regular glass with low amounts of impurities. If one was looking for the most efficient glass for their hood, quartz glass will allow the transmission of UV-B, but is not made specifically for light hoods.

And also remember, that if you have a rectangular garden, it is important to position the longest side of the reflector parallel to the shortest side of your garden. (from FAQ by Head Rush)

Additional note: you should periodically inspect and clean your light hood and bulbs, especially after foliar feeding or underleaf spraying for insects. The dust and dirt that collects will definitely decrease reflectivity. Isopropanol alcohol, glass cleaner or water (and a soft cloth) can all be used to remove streaks, dust and spots.

Contributed by: MedMan

There are a number of factors which play a part in the temperature radiated from your bulb, watts, hood design and air circulation for example.

A simple method of testing for temperature is to use the back of your hand; if its too hot for your hand, its too hot for your plants. Good ventilation is the key to getting your light closer to the garden.

Editor's note:

Recommended typical OLH distances:

Flourescents: proximimty

400w HPS: 1 foot

600w HPS: 1.5 foot

1000w HPS: 2 foot

125w envirolite 3"

200w envirolite 4"

If you are using a cool tube you can have your light alot closer to your plant's. If you are not using a cool tube you may still be able to get your light a little closer if you have very good air flow and extraction.


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Germing your seeds using the paper towel method!

Paper Towel Method!


Place one piece of paper towel or toilet paper onto a saucer, then place your seeds onto the paper towel and cover with another piece of paper towel and then lightly sprinkle the towels with luke warm (not hot) Brita filtered tap water (that has been standing for 24 hours) until all of the towels are wet/damp (

not soaking

). Then place a second saucer ontop of the first one and place the whole lot into a warm cupboard or alike.



Keep checking the towels every 4 to 5 hours to make sure they

do not dry right out

. If you see they are starting to dry sprinkle some more water over them until the towels are damp again and then replace the top saucer and place back in the warm spot. They can take from 24 hours to 5 days or sometimes even longer to germ so please be patient.


Once the seeds have sprouted and look like the ones in the picture you can plant them on. Be very careful not to touch or break the little white tap root.

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Wait Wait Wait :)! It sounds like you are missing informations here? Use the search, i bet many other did threads like this before. So my best advice for beginners here is to learn about the forum search. I bet it answers all the questions... But anyways thanks for the thread.

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hi i have looked and havent seen much about thats why im doing it here all together if it needs to be moved somewhere else where it will bee seen more i will be more than happy too just thought i would be easyer for someone that is starting hydro

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ok thanks i never seen the post where u said to give credit to the origanal poster i will have a look for there name and what site thanks for making it a bit better you can read it a bit better

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How Strong Are My Nutrients? â?¨EC and TDS Meters Explained

Any serious grower needs a sure fire method of accurately testing the strength of their source water, nutrient solution and run-off so they are equipped to respond to their plants’ ever-changing needs. So, to help us in our quest for perfect plant nutrition, we have all sorts of nutrient products, additives, meters, monitors, feed charts, calibration fluids and acronyms buzzing around our local grow store. You’ve probably heard people talk about the “EC” of their nutrient solution, or perhaps they talk in ppm (parts per million) – or they recommend you use a “TDS meter”. What’s with all this jargon? And how does it all fit together?

Well, we thought enough was enough. So we’ve put together this quick, no-nonsense and impartial guide to understanding how to measure the strength of your nutrient solution so we can all be clear about what we’re talking about – once and for all!

Worldwide, there is one standard parameter for measuring pH, but there are many more for measuring the strength of a nutrient solution. The two major measurements in use today are:

EC – Electrical Conductivity
TDS – Total Dissolved Solids


First, some basic concepts: when we add nutrients to water we create a nutrient solution. The more nutrients we add, the more concentrated the solution, and the more readily it will conduct electricity. So, the electrical conductivity (EC) of your nutrient solution can be seen as a quick and easy measure of how much nutrient is dissolved in it overall. Put another way, measuring the conductivity of a solution means measuring the electrically charged ions. Pure water will not conduct anything, but tap water already contains other minerals, metals and salts so it does conduct a small amount. Remember, it’s always important to measure your source water to see what you’re dealing with.
To measure conductivity we can use an EC meter, also known as a conductivity meter. It has two electrodes that, when dipped in the solution, measure its electrical charge by passing a small charge between them.
What is EC measured in?

Siemens are to “electrical conductivity” what feet or meters are to “length” – it’s the unit of electrical conductance. It’s important to get this distinction really clear in your head right now. EC is the scale (also known as the ‘parameter’) and siemens are the units. When dealing with the very low amounts of conductivity associated with EC in nutrient solutions, the preferred units are mS (millisiemens; one thousandth of a siemen) and µS (microsiemens, one millionth of a siemen) per centimeter.
EC is the most widely accepted measurement for the strength of nutrient solutions, and is the standard in Europe and many other parts of the world. The one notable exception is North America which prefers to use TDS.


TDS (Total Dissolved Solids) is the preferred scale for measuring the strength of a nutrient solution here in North America. It quantifies the concentration of dissolved solids contained in a solution. TDS is arguably a better parameter for measuring nutrient concentration, since it measures by quantity or weight. In other words, you can have two glasses of water with equal parts TDS but different EC levels, since one glass may have more or less conductive elements (say salt vs. calcium.)
The problem is that a true TDS measurement is difficult to achieve (and would also defeat the purpose since evaporation is required). Therefore, if one wants to eliminate the estimating that the conversion factor does, an EC meter is better. If we lived in a perfect world, and every nutrient company and TDS meter used the same non-linear scale, a TDS meter is preferable. But since there are so many different variables, an EC meter lends itself to more consistency.
What is TDS measured in?

Once again – make sure you get your head around this – TDS is a scale, or a parameter, just like time, length, temperature and volume. The unit of TDS is ppm (parts per million.) A TDS reading of 50 ppm means there are 50 milligrams of dissolved solids in each liter of water, or 50 mg/l.
How do TDS Meters work?

If EC meters (conductivity meters) work by measuring conductivity in a nutrient solution and expressing this in siemens, how to TDS meters work out how many parts of nutrient there are per million of water? Sorry to break it to you, but the answer is, they don’t.
TDS meters work in actually the same was as EC meters! Both measure the electrical conductivity of the nutrient solution they are dipped in. The difference is in how the information is displayed.
A TDS meter will measure the electrical conductivity, and then use a conversion factor to display the strength of the nutrient solution in ppms. Now here’s the slightly tricky bit. The conversion factor from EC to TDS varies from meter to meter.
Conversion Factors

NaCl is a conversion factor based on Sodium Chloride (regular table salt.)â?¨The conversion factor range is 0.47 to 0.5.â?¨Non-linear meters based on NaCl typically use: 0.5 x the EC level (if converting from µS to ppm or mS to ppt) or 500 x the EC level, if converting from mS to ppm.
TDS 442™â?¨â?¨442™ or Natural Water™ is a proprietary scale based on properties of naturally occurring fresh water. The 442™ part is an abbreviation of 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride.
The conversion factor range is 0.65 to 0.85.â?¨Non-linear meters based on 442™ typically use: 0.7 x the EC level (if converting from µS to ppm or mS to ppt) or 700 x the EC level, if converting from mS to ppm.

KCl is a conversion factor based on Potassium Chloride.â?¨The conversion factor range is 0.5 to 0.57.â?¨Non-linear meters based on KCl typically use: 0.55 x the EC level if converting from µS to ppm or mS to ppt) or 700 x the EC level, if converting from mS to ppm.
TDS 640

A less popular conversion factor.â?¨The conversion factor range is 0.64 to 0.67.â?¨Non-linear meters based on 640 typically use: 0.64 x the EC level if converting from µS to ppm or mS to ppt) or 640 x the EC level, if converting from mS to ppm.â?¨â?¨Yes, four different possible conversion factors means that four different meters that give measurements in ppm may all give different readings from the same solution! However, all EC meters should give the same reading in the same solution as there’s no conversion factor necessary.
I know, I know … TDS sounds like a confusing thing – but it’s really just a measure of the total ions in solution. For every gallon of water you have X mg’s of stuff in it. If one of your friends starts talking about their nutrient solution in terms of TDS, be sure to find out what scale they are using. Many growers, especially in Europe, in an effort to avoid confusion, use EC. If you are still confused, contact the manufacturer of your nutrients and find out what they recommend. Remember to ask them what TDS scale they use if they give you dosages in terms of ppm.
Likewise, if you are working with a TDS meter that only has a ppm display, remember you need to be sure of the conversion factor being used. TDS comes into its own when you need to measure individual elements in applications such as nutrient and water quality, tissue analysis results and soil analysis. Results from these laboratory tests will give individual elemental readings in ppm or mg/l. Remember, a TDS meter will only give you an approximation of the overall nutrient concentration, based on the conversation factor used.
Below is a table to show the relationship between the various methods of displaying the strength of a nutrient solution.
EC (mS) EC (µS) TDS NaCl
(EC µS x 0.5) TDS KCI
(EC µS x 0.55) TDS 640
(EC µS x 0.64) Natural Water™ 442
(EC µS x 0.7)
0.6 600 300 330 384 420
1.2 1,200 600 660 768 840
1.8 1,800 900 990 1,152 1,260
2.4 2,400 1,200 1,320 1,536 1,680
3.0 3,000 1,500 1,650 1,920 2,100
Jargon Buster

EC = Electrical Conductivity
TDS = Total Dissolved Solids
PPM = Parts Per Millionâ?¨PPT = Parts Per Thousand
µS (or µS/cm) = micro-Siemens (one millionth of a siemen.)
mS (or mS/cm) = milli-Siemens (one thousandth of a siemen.)
NaCl = Sodium Chloride (EC-to-TDS conversion – EC x 0.5)
KCl = Potassium Chloride (EC-to-TDS conversion EC x 0.55)
442 = 442 Natural Water™ (EC-to-TDS EC x 0.7) (The “442” is an abbreviation for 40% sodium sulfate, 40% sodium bicarbonate and 20% sodium chloride.)

Making Sense of your Meter

Here are some popular TDS meters along with their conversion factors, where applicable.

TRUNCHEON Displays EC and both NaCL (0.5) and 442™ (0.7)
GUARDIAN Displays EC and both NaCL (0.5) and 442™ (0.7)

HI 98300 0.65
HI 98301 / 98302 NaCL (0.5)

HI 981404N / HI 981405N
442™ (0.7)
HI 983301N 442™ (0.7)
HI 983301N/5 NaCL (0.5)

TDS-3 NaCL (0.5)
AP-2 None – just measures EC
COM-100 Displays EC and TDS (user can select NaCl, 442 or KCl factors)

EcoTestr, TDSTestr11, PTTestr35 User Adjustable TDS Factor between 0.4 and 1.0

Default setting: 0.71

MW401, MW402 NaCL (0.5)
T75, T76 NaCL (0.5)
C65, C66, MW301, MW302 None – just measures EC
MW801 NaCL (0.5)
MW802 0.65

Tri-Meter 202 NaCL (0.5)
Tri-Meter 203 442™ (0.7)
Handheld 442™ (0.7)
Towards A Clearer World

There is a drive towards some standardization in the hydroponics industry to create less head work for all concerned. Nutrient manfacturers, if you specify dosage with in ppms, please also state what TDS scale you are using. This includes calibration fluid!

Should I use Lavarocks or Expanded Clay?

Gravel, sand, perlite, rockwool, oasis cubes, coco, expanded clay (?poprocks? or Hydroton/Groton/ L.E.C.A. and other names), and lava rocks are common choices for Hydroponic mediums.

Lava rock and poprocks are popular as they are inert, do not absorb water, provide good aeration, are Ph neutral, and can be re-used.

Which is better?

Both of these mediums have advantages and disadvantages, depending on the system and requirements. Lava rocks work better in some systems, poprocks in others. They are good for drip, nft, flood&drain and for filling mesh pots.

Both types should go into a system that irrigates frequently, as Hydroton and lava rocks are non-porous and have little water-holding capacity. Both types should be pre-washed and sterilized to remove dust & mold.


Thanks to: PhilcuisineLavarocks are a cheap and readily available medium. They are good for large bucket grows where stability is a necessity.

(Aiptasia)"... consists of feathered basalt which is pH neutral. Basalt can carry trace metals, and my big lava rocks rust from the trace metals..."

Attached Image

Lavarocks are a cheap and readily available medium. They are good for large bucket grows where stability is a necessity.

(Aiptasia)"... consists of feathered basalt which is pH neutral. Basalt can carry trace metals, and my big lava rocks rust from the trace metals..."

(Snaps_Provolone) "Lava rock is chunks of red, porous (VERY porous!) basaltic (volcanic) rock. I've purchased it both by the bucketful, and by the bag at any place that sells landscaping materials. It is much lighter than, say, peagravel, but still rather heavy.

Only rockwool (MUCH more $ than lava rock) has more air/nutrientfilm capacity. Lava rock has REAL good capillary action too. Once wetted (I use flood-drain/ebb flow), it holds VAST amounts of water, while affording roots WAY more space to devolop than rockwool EVER can."

Lava rock is good for ebb-flow/flood-drain, or top-drip systems, but can also be used successfully in an airated standing solution.

I still prefer Hydroton though, it stays moist longer and lacks that sharpness that tends to be harmful to soft tissue.."


# Heavy. Roots will become damaged if a plant shifts; heavier lava rocks will help stabilize a large plant, preventing it from leaning or shifting during growth.
# Chemically inert and reusable. Does not absorb water.
# Lava rocks ?lock? together to give a more solid and stabile medium to plant in. Large plants are less likely to shift.
# Easy to find, usually inexpensive
# Lava rock come in large, medium and pellet sizes.
# Individual rocks can be hand-placed to anchor air stones, drip lines, stakes, etc. Stakes embedded into the rocks will be solid.
# Lavarocks can take a beating and not fragment or crush easily


# Lavarocks need to be pre-soaked to clean them of grit and stabilize the pH:
(raygun) "if you use the lava rocks just make sure that you rinse well and soak them in ph balanced h2o for 3-5 days then rinse and use."

# Lava rocks are a pita to clean. They have irregular surfaces and micropores that roots and bacteria love to fill. 100% sterilization is never guaranteed. Some growers consider them one-grow disposable.

(the colonel) "i find it easier to just buy new lavarock and rinse/clean it all than to reuse it: scrub each individual lava rock clean off all traces of root, and then disinfect and then rinse real well to get all the disinfectant chemical out.. but thas just me"

# Lava rocks are heavy. This makes everything heavier, harder to haul/move, and more expensive to ship.

# Lava rocks may contain traces of heavy metals, which may cause nutrient deficiencies and pH swings.
# Irregular rock shapes provide uneven aeration and wetting in the rootzone. Roots will be less able to penetrate evenly throughout the medium

(raygun) "I did not like using the clay by itself as it did not disperse the ater from my drip tube and I ended up with dry spots in my pots. The lava roxs are all shapes and sizes which help change the path of the falling water."

# More difficult to fill containers

Expanded clay / Hydroton

Attached Image

# (Son-T) ?Hydroton: This Lightweight Expanded Clay Aggregate (L.I.C.A.) is manufactured exclusively at high-tech kilns in Germany and is used as a soil replacement in hydroponics. Composed of shale that is pelletized and fired, Hydroton holds water extremely well and transmits it effectively. The pellets are uniform in size and have an attractive, natural appearance. Hydroton is chemically inert, has neutral pH, is reusable, clean and odorless.?

(nuniabiz) "clay balls at like 2800 degrees which expands all the little bubbles in the clay making the surface area something on the order of 100 times greater theres for holdin more o2 and wicking more H2o purrrrrfect"

The high temperature sterilizes the Hydroton, but mold can still form in the bags due to condensation and breaks.

(OzHornet) "marble-sized orange/brownish balls you can get from nurseries or hydro stores - often used in aeroponics; very cheap"

Poprocks are the preferred medium for hydroponics.


# Expanded clay is much easier to clean. The round balls of clay have a smooth surface coating that can be cleaned of roots and bacteria.
# Chemically inert and reusable
# Different sizes available
# Lighter than lava rock
# Poprocks are more uniform in size & shape. They can be poured into containers, and they fill containers evenly.

# The round pebbles do not compress or touch. The uniform space between the pebbles provides even aeration and wetting throughout, allowing roots to fully grow into the medium. The clay surface repels water, but surface tension coats each clay ball in a thin coat of water ? perfect conditions for roots. Cracked rocks absorb water like a sponge.

# The round pebbles have more surface area than the flatter lava rocks, proving more area for roots to cling to.


# Can be more difficult to source

# Poprocks are round and as such are less stable to plant in. Larger plants may shift if disturbed, damaging their root systems.
# Poprocks both sink and float! Poprocks can clog drains and tend to go everywhere. Knock a pot over and you?ll be picking up pebbles for a long time

# Poprocks need to be thoroughly pre-washed to remove the heavy clay dust that is caused by the balls rubbing together during transport. Clay dust will still come off them and may require a flush of the system upon startup. Heavy clay residue will settle to the bottoms of systems and may clog pump filters.

# Poprocks will slowly break down, as they are exposed to acidic nutrient conditions.
# Poprocks can break, shatter and become crushed with handling

Rinsing tip for both lava and pop rocks:
(tdmaker) ?Simply, poke holes in the bottom of the bag and cut open the top. With a water hose, run water through the top of the bag. The red powder will flow from the bag through the holes in the bottom. Oh, and do this outside. Otherwise, do smaller amounts indoors?

Should I sterilize my used medium or encourage bacteria?

(10k) As far as harboring beneficial bacteria, user 'Jackerspackle' wrote some extensive material on this several years ago.

Basically what he said and I believe and practice, is that expanded clay mediums harbor them too. Just dont sterilize your rockage when washing them out and you'll have plenty remaining in and on the medium to replenish the next grow as soon as they're rewetted. Bactors like nitro simmonas and nitro bactors can go dormant in a dried out state, but will become "alive' again as soon as they're moistened. Of course, you'll keep a more robust living culture going if you dont allow the used rock to ever dry out completely.

The only time when a grower would really want to sterilize the rocks is if he had suffered a root disease in the previous grow. A gnat infestation is NOT a good reason to sterilize the rocks since they can easily be treated using BTI bacteria and semi-sealing up the wetted bag (or tub) full of rocks for a week or so to prevent the life cycle from any possibility of continuing, but keep an air stone running in the closed up wet bag or box of rocks to help keep the bacteria colonies thriving.

What are the differences between aeroponic misting and fogging?

The difference between fog and mist is the particle size generated.


Any water droplet smaller than 50 microns is considered fog. There is 'wet' fog and 'dry' fog. Wet fog has a particle size in the range of 10-50 microns. Dry fog is produced by ultrasonic systems and has particles in the range of 2-10 microns.

Attached Image

Dry fogging systems use very little water, but they do require a high quality supply (ie. R.O. or distilled), as they are prone to clogging.

Attached Image

fogging systemThe disadvantage of dry fogging systems is that they are no good for cooling, since the quantity of water available for evaporation is small. Wet fogging systems can be run to excess during summer and the surplus fog can be vented.

Fogging systems require additional watering of the cuttings, unlike conventional misting systems.

Attached Image

Misting systems are the cheapest to set up and run, but fogging systems may give better results with some plant species, for example some Verticordias, Brachycome, lavenders, and many species with hairy or finely divided leaves.


Misting maintains a fully saturated atmosphere around the cuttings, whereas fogging aims to keep the leaves cool. Reducing leaf temperature reduces the water vapor pressure within the leaf and less water escapes. However, a fully saturated atmosphere will not entirely prevent transpiration water loss from cuttings. If the leaf temperature exceeds the air temperature, then the internal vapor pressure will be greater than the surrounding air, and there will be evaporation from the leaf. To avoid this, shading is necessary to prevent high leaf temperatures.

(Nigel_Samhain) The foggers usually use a diffuser, although they call it a ceramic disc coated with what appears to be brass. These foggers produce vapors in the 2-15 micron range. When applied to the root system, it is comparable to growing your plants within a cloud.

Attached Image Attached Image

Foggers experience calcification.

Usually it can be cleaned off with a dilute solution of White vinegar. When the EC of the solution is high, the calcification occurs at a much greater rate.

It is recommended that the fog be dispersed in increments, rather than remain constant, to cut back on diffuser wear. This also tends to make the roots strive for faster growth.

What is nutrient lockout?

Nutrient lockout happens when your plant can not access specific, or all nutrients in the growing medium, this is due to a chemical reaction within the medium/solution which prevents nutrients from being absorbed by the roots.

Aged nutrients can precipitate in the bottle, causing some of the ingredients to become solids or even evaporate, the same problem may also occur in the growing medium.

Lockout will display the same symptoms as nutrient deficiency; to help control this problem dispose of old liquid feed containers as you would old medicine and use fresh nutrients from a bottle that has been recently opened.

The following points can also be responsible for nutrient lockout.

* PH is incorrect or fluctuates.

* Single pack hydroponic solutions.

* Salt build up.

* A chemical reaction between 2 or more nutrient
solutions that are mixed together.

For acute deficiency symptoms caused by toxicity and nutrient lockout a first Aid program should be immediately administered.

Step 1)
Leach the plants roots and growing medium using a professional leaching agent to thoroughly leach away metals, calcium, sodium, chlorides, sulphates and many other compounds, which can build up in the growing media.

Step 2)
Feed with 1/4 strength high quality complete plant food mix along with a high quality vitamin B-1 product such as Superthrive (1 drop per gallon).

Step 3)
Spray a professional stay green formula on the leaves. After 24hrs, spray the leaves with a quality vitamin B-1 product.
Feed at 25% of recommended fertilizer dosage until first signs of growth.

How do I sterilize and disinfect my system?

Sterilizing and maintaining clean conditions inside your hydroponics/aeroponics systems is extremely important. Keeping cloning, vegetative and flowering systems clean gives your plants a fighting chance against pythium (root rot) and other harmful diseases, ensuring healthy and vigorous crops.

Cleanliness is particularly important in closed (recirculating) hydroponic/aeroponic systems due to the favorable conditions these systems present to water and airborne diseases. Failure to periodically clean a system can result in stressed plants becoming infected and rapidly spreading disease throughout the entire system. Once infected, the entire crop will experience reduced vigor and yield.

Prevention is the best ‘cure’ for disease. Sterilization between crops, adding anti-pathogen additives, and attention to system design can help combat disease.

· Hot water
· 35% hydrogen peroxide (3% and 17% available at pharmacies, 35% at hydro stores). Oxidizes, then quickly (24 hrs) degrades to water (Sterilizing strength for 1-4 hours).
· 99% Isopropyl (rubbing) alcohol. Kills bacteria and viruses on contact.

Note: bleach is not recommended. It leaves a toxic residue.

Daily/weekly system maintenance:


· Dip your portable ph/tds/temp tester(s) in Isopropyl alcohol, then rinse with water before testing solutions to minimize contamination between reservoirs. When taking a reading, submerge only the sterilized portion of the tester into the reservoir.

· Periodically inspect roots for signs of pythium. Consider pulling any plants with these symptoms.

· Add 1.5ml 35% h2o2/gallon. H2o2 can attack beneficial bacterial; H2o2 use is not recommended when using these enzymes. H2o2 at low concentrations can add beneficial oxygen to the reservoir without killing these enzyme additives.


· Mist all tools, transfer buckets, etc with isopropanol alcohol in a spray bottle, then rinse with water before use.

· Weekly or bi-weekly nutrient changes are recommended. (Go longer if using enzymes to maintain).

· Remove and soak all pump filters/gaskets, thermometers, strainers, air stones, etc in strong h2o2 + hot water.
· Wipe away salt and slime buildup
· Add Guardian Angel or other pythium-inhibiting enzymes to tank (weaker h2o2 strengths are recommended when used in conjunction with these biological additives.) Maintain enzyme strengths.

System sterilization:

Wear gloves when handling concentrated peroxide. Do not use bleach.
Strong h2o2 will not ‘burn off’ slime and salt buildup by itself.

· Remove all plant matter from system
· Pre-flush netcups/pots with water and inspect to ensure all roots have been removed. Put netcups/pots in dishwasher, then remove and soak in strong h2o2.
· If infection was present, replace any grow medium; soak gro-rocks in strong h2o2
· Recommended: remove and replace all irrigation. Biologically-resistant poly tubing is can be cleaned and re-used.
· Soak all ‘accessories’ in strong h2o2 (misters too, if possible)

system cleaning

· Remove and sterilize reservoir by initally flushing with water and wiping with a clean cloth, then spraying 50% h2o2 with a spray bottle on all surfaces. Wait for one hour, then thouroughyl flush with water twice.

· Flush system with water and do a pre-wipe (hot water + h2o2) to remove salt and slime buildup on all system surfaces.
· Mix up a very strong (ie. 20%) H2o2 solution and spray it onto all system surfaces and allow to dry.
· Run re-connected system with 10% h202 + hot water for several hours, dump, and flush again thoroughly with water. Don’t plant right away!

General advice:

· Do not share tools and other equipment between systems or reservoirs. Isolating systems will contain any problems. Keep separate and dedicated transfer buckets, measuring cups, trays and other equipment; do not share between systems.
· Keep your moms healthy and vigorous! Pythium will pass systemically to clones.
· Inspect and remove unhealthy/slow growing plants early.
· Use a pond strainer to keep leaves and debris out of tank
· Tap water often contains elevated levels of chlorine to inhibit bacteria

System design considerations:

· Isolate systems with separate tanks, irrigation and pumps.
· Use reflective surfaces (mylar, white poly or titanium paint) to keep the root zone cool between misting periods.
· Keep system light-tight. Cover tank (but do not seal).
· If possible, use low-cost UV / biologically resistant poly irrigation hose to minimize residue buildup. Pvc plumbing is difficult to inspect and clean.
· Maintain nutrient temperatures in the 65-70F range for optimum growth and o2 saturation.
· Maximize o2 levels in your system: waterfall-drop your nutrient return, use airstones/venturis/skimmers
· Frequently circulate nutrient solution to avoid stagnant water

hi all i never sat and write all this myself its info i found off other sites this is from uk420

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A Guide To Watering

Figuring out when to water your plants can be tricky, especially for new growers, so hopefully this quick thread will help.

After over-feeding, the most common cause of plant failure is over-watering! The roots need air as well as water and should not be constantly drenched. The symptoms of over-watering are unfortunately very similar to under-watering... the plants wilt, the leaves and branches sag, brown patches appear on the leaves, the roots start to rot and if left untreated the plants die.

How often should i water the plants and how much should i give them?

There is no definite answer as it depends on many things:.. warmth of the grow-room, the light's used and distance from the plants, humidity, size of pots, growing medium (soil) and various other factors.

There are a few things to look for when deciding when to water:

* Is the pot very light? - Around 90% of the weight of compost is water, so if the pot is light and much easier to pick up than normal, a watering is needed.

* A gap around the edge of the soil in the pot? - Soil shrinks as the water is used up, so a gap around the edge of the soil is a good sign that water is needed.

*Does the soil stick to a pencil? - Gently push a long pencil into the edge of the soil in the pot, if it is not damp with bits of moist compost stuck to it when you take it out, then a watering is needed.

* Wilting? - A plant will wilt (droop) when it needs watering, usually starting at the lower leaves working up the plant. If your plant is wilting then a watering is urgently needed.

How Much?

Again this can vary dramatically depending on pot and plant size etc, but what most growers do is:.. with a tub/tray under your pot, water *slowly* until the surplus runs from the drainage holes at the bottom of the pot... allow the pot to stand in the surplus water for 10 minutes to soak up any more that is needed before emptying out the run-off tub.

The smaller your pots the less water you will need to give... a little 4" starter pot for seedlings may only need watering once a week with half a pint of water, whereas a 10 Litre pot holding a big plant may need 3 or 4 litres of water 2 or 3 times a week!

Remember, wait until the pot is light and the compost dry before watering again, and just because the top inch of soil is dry doesn't mean that the soil around the roots is!

As with feeding your plants, a good rule of thumb when watering is: better to give less than too much!


Hope that helps a few of ya!

all this info is from i never sate and write it all out no credit for me but to the previouse person that done it thanks

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@smokey: In some points you are right. The search is very slow. If i search for hydro and use the pager it takes over 30 seconds until the page responds. So it is a little bit tricky to come to good postings. Thats true!

Again... thanks for your work bro!

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Explosion of informations on one topic .... This one is like bomb.. Keep bombing))

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Damn there is gonna be lots of reading on this post ^^

Thanks for input man i'm sure it will help someone some day ;) Perhaps me when i'll decide myself to go in hydro mail

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hi to all again i seen this and thought it will come in handy for people that gro in rockwool i got this information thank cannabis giving

How To Grow Marijuana In Rockwool

The book is written by one of Holland's experts in the field of professional hydroponics. If you have this book, you know everything there is to know about growing on rockwool. This book is found all over the internet on many websites.

Rockwool - the book on how to grow marijuana in rockwool.

ForewordThe number of people who grow cannabis for themselves keeps increasing. Some of them raise it in a small, modest garden for their own use; others for commercial reasons. A great deal of experimentation has been done with cannabis in The Netherlands, and through the years, further improvement took place.

Dutch weed can measure up to the best foreign varieties. After growing only in soil for years in The Netherlands, other growing methods can expect new interest. Some people grow on hydro-culture (granules), but also, growing on rockwool substrate occurs more and more. It is a clean, efficient way to raise cannabis. Relatively little has been written about growing on rockwool. Surprising, on the face of it, because in professional horticulture rockwool is being used since long. Growing cannabis on rockwool appears to go very well.

Who would have expected anything else from this indestructible weed? For this book, we have drawn from the experience of growers of the produce we ordinarily buy from the green grocers. The specific expertise of professional weed-growers is also used. Their advice is appreciated; - without mentioning any names. This book is meant for everyone who wants to grow cannabis at home. The emphasis is on growing on rockwool substrate, and on (semi-professional) climate control in the grow space. The first section takes a look at to the wanderings of cannabis throughout the world, and to how plants, in general, are cultivated. The second part is principally concerned with what is needed for growing cannabis indoors, and about the details of climate control. The third section deals with growth itself, with attention paid to plant diseases and insect pests.

We wish the reader enjoyable reading, lots of success at growing, and again, much pleasure with use.

Table of Contents

Foreword 3

glossary 7

Part I: Introduction

1. The history of cannabis 15
1.1. Preface 15
1.2. The journey 15
1.3. Marijuana in the Netherlands 16

2. Physiology of plants 19
2.1. Preface 19
2.2. Principles of growth 19
2.3. Osmotic processes 23
2.4. Intake and circulation of materials 26
2.5. Factors influencing the growth of plants 29

Part II: Necessities and climate control
3. Necessities and basic installations 30
3.1. Preface 30
3.2. The growing space 31
3.3. Shopping list 32
3.4. Growing space layout 35

4. Light 41
4.1. Preface 41
4.2. Choice of lamps 42
4.3. Using high-pressure gas lamps 46
4.4. Proper lighting for cannabis 47

5. Air 49
5.1. Preface 49
5.2. Influencing air quality 49
5.3. Relative humidity 53
5.4. Temperature 55

6. Water 57
6.1. Preface 57
6.2. Water quality 57
6.3. The irrigation system 64

Part III: Growing cannabis

7. Plant growth 70
7.1. Preface 70
7.2. Cloning hemp 70
7.3. The vegetative phase 77
7.4. The generative phase 79
7.5. Harvesting and drying 81
7.6. Skuff 83
7.7. Setting up the garden again 84

8. Diseases and insects 86
8.1. Preface 86
8.2. Diseases 87
8.3. Pests 90
8.4. Summary 96

Index 97


Acidity - Defines the measure for the uptake of nutrient salts by the plant. Acidity is indicated by the pH value.
A pH value of 5.8 is ideal for the cultivation of cannabis.

B - Abbreviation for boron, a material necessary in very small quantities for the growth of cannabis.

Blue light - Light given out by mercury-iodide lamps which is necessary for the formation of chlorophyll in plants.
Blue light has a wavelength of approximately 445 nanometers

Ca - Abbreviation for calcium; necessary for osmotic processes in the plant

Chlorophyll - The official name for 'leaf-green'. Chlorophyll gives the plant its green color,
and is important in the conversion of CO2 and H2O into glucose.

Clones - Weed-growers' jargon for cuttings.

CO2 - The chemical formula for carbondioxide; next to water, the most important basic material for the growth of plants.

C6H12O6 - Chemical formula for glucose, the basic material used by plants for growth and flowering.

Dark Part of photosynthesis. During response, the dark reaction, the actual formation of glucose from water and
carbondioxide takes place.

Deficiency Plant disease brought on by the disease-application of too little of a certain fertilizing material.

EC - Electrical conductivity. The electrical conductivity standard of water, which can be measured with an EC meter,
tells whether or not the composition of the fertilizer is correct

Fe - Abbreviation for iron; an element in the nutrient solution.

Generative phase - The flowering phase of plants. When cannabis is cultivated indoors, this phase begins, at maximum,
one week to ten days after a clone with roots is planted, and continues, depending on the variety,
two to three months.

GH - Abbreviation for 'German hardness', a scale for the hardness of water
(namely the quantity of calcium) indicated in degrees.

High- Cultivation under artificial light pressure makes use of high-pressure gaslamps.
They give out the desired quantity of light with the desired wavelength.
(High-pressure sodium lamps - red light for growth, mercury-iodide lamps -blue light for the formation of chlorophyll.)

H2O - Chemical formula for water, consisting of two parts hydrogen(H), and one part oxygen (O).

Hygrometer - A meter with which the relative humidity can be established

Hygrostat - An apparatus which maintains correct relative humidity. A good hygrostat keeps the relative humidity constant in a room.

Internode - The distance between the leaves and the tops of a plant.
When light only from the red spectrum is applied during the generative phase, the internodes become longer.

K - Abbreviation for potassium, which is, next to nitrogen and phosphate, one of the primary nutrients for plants.

Light Part of photosynthesis in which response photolysis takes place.
Photosynthesis also includes the dark response, in which the actual formation of glucose occurs.

Lumen - The international measure for luminosity from a light source.

Ma - Abbreviation for manganese, an element used in very small quantities by plants.

Membrane- Membrane allowing small molecules to pass through but not the larger ones.

Mg - Abbreviation for magnesium, an element plants need for the build-up of chlorophyll, and for osmotic processes.

Micro-element - Nutrients the plant only barely needs; for example, copper and zinc.

Millisiemens- The international measure for electrical conductivity.

Nanometer - Measure of length used to express the wavelength of light.
Red light travels at a wavelength of approximately 650 nanometers(nm), blue light at approximately 450 nm.
A nanometer is one thousand millionth of a meter(10-8m).

NPK - Abbreviation for nitrogen (N),phosphate (P), and potassium(K), the three primary nutrients for plants.

Osmosis - The phenomenon in which water containing a dissolved substance of a low concentration is absorbed
via a membrane into water which contains substances of higher concentrations (for example in plants).
Osmosis is very important to plants for sturdiness, and for the transport of water and nutrient materials.
Pressure is built up by osmosis, making the plant sturdy. If this pressure falls, the plant loses its sturdiness.

P - Abbreviation for phosphate, one of the three primary nutrients.

pH - The pH is a measure of the acidity of a solution (for example, water with nutrients).
The pHscale goes from 0 to 14.
The lower the pH value, the more acidic the solution

Photolysis - Part of photosynthesis, in which water (H2O) is split up into hydrogen (H), and oxygen (O).
This occurs during the light response.

Photosynthesis - The chemical process in plants, in which carbondioxide and water are converted into glucose
by the influence of light energy

Phototropism- The inclination, which plants have, to grow towards light

Physiology - The science of growth. (Plantphysiology is the science concerned with the growth and flowering of plants)

ppm - 'Parts per million'.
The amount of material in the air, of CO2, for example, is expressed not only in percent,
but also in ppm. 0.03% CO2 in the air is equivalent to 300 ppm.

Predator - A predator is an insect that protects plants against other insects such as spider mites, white flies, and thrips.

Red light - Light needed by plants in order to grow. Red light has a wavelength of approximately 650 nanometers.

RH - Abbreviation for relative humidity. The relative humidity is expressed in %, and measured with a hygrometer.

S - Abbreviation for sulphur, a nutrient which plants need only in small quantities.

Salts - Nutrients, such as NPK, but also other materials (Ca, Mg, etc.) which are dissolved in water so
they can be fed to the plant. We call the solution of such materials salts.

Semi-permeable walls/membranes permeable - Play a role in osmotic processes in plants by which the transport of water
and nutrients takes place, and the plant gets its strength.

Skuff - Sifted tops, from which you get as-pure-as-possible THC.

Stoma - An organ in the leaves of plants. The stomata allow the plant to breathe. Oxygen and excess water are
released through the stomata.

Substrate - The 'soil'. Thus rockwool substrate means 'soil of rockwool'; the growth medium.

T-44, T-77 - Measures for sieves with which you can sift out THC resin.

THC - tetra-hydro-cannabinol.

Trace Element Marijuana Molecule

Trace-element - Another name for micro-element, nutrients the plant needs in only minute quantities, such as boron and manganese.

Vegetative- The growth phase of plants.
This lasts phase - only a short while in the cultivation of cannabis;
from one week to ten days maximum.

Zn - Abbreviation for zinc, a nutrient which plants need in small quantities.

PART I: Introduction

Osmosis Filter for Cannabis


Chapter 1: A Short History of Hemp in the Netherlands

1.1. Preface

This book is not about the enjoyment of smoking or eating marijuana and hash. We can conclude that the home grower knows how to estimate the value of his or her own product, can't we? We'll just leave those stories about the nice feeling for what they are. We spend no time on the effects of cannabis products. Everyone knows what a good 'high' feels like; what you have to do, and what you sometimes have to allow to happen. This first chapter deals with the history of cannabis in the Netherlands. This way, you get a little insight into how the plant has come about in the Netherlands, and what purposes the cultivation of cannabis has served in the last centuries.

1.2. The journey

China is known principally for its tea and opium, the great number of its people, and the hughe amount of Chinese restaurants. also hemp originates from China. The Chinese were already cultivating cannabis 4500 years BC. They were able to spin yarn for clothing, and make fishing nets and rope with it. The first medicinal applications were described two thousand years later. It was used for rheumatism, gout, malaria, and a number of other disorders.

Overfertilized Marijuana Plant

overfertilized plant

From China, hemp travelled to Arabia, and appeared in the writings of the Greek philosopher Herodote. He describes ritual use of burning hemp by the Syrian Skytes.
Hemp grows everywhere. It came to Europe via India and the Roman Empire. In the Middle Ages, hemp's intoxicating effect was described by Boccaccio and Rabelais, among others. Later, it was used by Victor Hugo, Honoré de Balzac, and Alexandre Dumas in the Latin Quarter in Paris.

Scholars do not agree as to whether the Spaniards were the original importers of cannabis to America. It is certainly true that Colombus' ships were outfitted with hemp rope, and sails made from hemp cloth. The plant spread quickly in America, and at the beginning of the seventeenth century, large-scale hemp plantations proceeded in order to supply the needs of the ship- and clothing industries.

1.3. Marijuana in the Netherlands.

It wasn't any different in the Netherlands. It's not exaggerated to suggest that a considerable portion of the wealth of the Golden Age came from the cultivation of hemp. Some 11,000 ships sailed at that time, rigged with rope and sails made of hemp. Hemp was the leading agricultural product in the Netherlands; the stalk was primarily valued. The stalk, only from the male plant, was processed into hemp fiber. The female plants were used for other purposes. These were harvested later, and then threshed. The seed was used as bird feed, or was processed into oil, green soap, and raw material for paint. For the latter application, a thick pulp remained which served as animal food. After the Golden Age, less and less hemp was cultivated in the Netherlands. Competition arose from cheaper Russian hemp, along with other fibrous materials such as coconut and sisal. The steam engine made its entry, so less rope and sails were needed in the shipping industry.

Just as in other countries, the medicinal effects of the plant did not go unnoticed by its growers. Rumours had it that witches used hemp in their witches' salves. The effects of hemp had already been described in "The Herb Book" by Rembert Dodoens in the sixteenth century.

Using cannabis products for pleasure really didn't come about in the Netherlands until after the Second World War. After jazz, and later the hippie influences, marijuana smoking blew over from America. In 1962, Simon Vinkenoog a Dutch liberated poët, wrote: 'In ten years, this will be as common as drinking whiskey or beer, or just as normal as an ordinary cigarette. And it doesn't give you lung cancer'. In the first decades, youbetter smoked imported hash than 'Nederweed'. Still, growing at home was so energetically pursued, that, thirty years later, Dutch weed ranks as the best in the world. There has been improvement, cross breeding, and cloning; fighting the currents, at first. Until the mid-Seventies, growing, possessing, and use of soft drugs was still punishable. Not until after the mid-Seventies tolerated points of sale originated - the coffeeshops.

Molecular CO2 intake of a marijuana plant.Co2 in nature.

CO2 intake in the leafs Light, air and water, the bare necessities

And now it seems there's no stoppping it. more and more of people use soft drugs, and more and more people try to hold down the costs of soft drug use by going to work for themselves. Sometimes, purely for their own use, sometimes to earn a few cents, sometimes to get rich.

This book has been written for the growing group of people who want to apply themselves to home cultivation. Now, this is the place to give a few warnings. In the first place, it may be generally presumed that smoking is not considered the best thing for your health. In the second place, even though the Dutch government has become more open-hearted in its tolerance of the growth, possession, and use of cannabis, the substance still stands on List 2 of the law on narcotics.

That doesn't pose a problem anymore, if it's for your own use, but for large-scale growing, possession, and dealing - it still does. Grow-gardens, green-houses, and plantations are still searched out and destroyed, and a considerable fine usually follows. Ultimately, every home grower has to gain knowledge and experience before there can be talk of a good yield. So, don't get discouraged too quickly if it doesn't go perfectly in the beginning

Chapter 2: Physiology of Plants

2.1. Preface

To achieve good results, a home grower must know about plant physiology. Plant physiology is the part of biology which is concerned with the way plants grow and flower. In this chapter, the priciples of plant physiology are discussed. With the growth and flowering of plants, it involves a select combination of light, air, and water. For light, it's about sunlight for outside growing, a combination of sunlight and artificial light for greenhouses, and just artificial light for inside growing. For air, the amount of carbon dioxide (CO2) is of principal importance. Water performs various functions. Plants need water (H2O) for the growth process, but also to transport other important materials.

Wooden Frame

wooden frame

2.2. Principles of growth

Plants change CO2 and H2O into glucose under the influence of light. Glucose is the chemical building block for the structure and sturdiness of the plant. From glucose, the plant makes cellulose, the material which gives plants their fibrous structure. (Glucose is, in fact, stored light energy). The chemical process in which carbon dioxide and water are converted into glucose is called photosynthesis (from the Greek 'photos' = light, and 'synthesis' = to compose). Chlorophyll, which also gives plants their green color, is indispensible for this process. If all the conditions are right, the following chemical reaction occurs:

6CO2 + 12H2O = C6H12O6 (glucose) + 6O2 (oxygen) + 6H2O

We can deduce a number of things from this formula. To get one part glucose, we need six parts CO2 and 12 parts H2O. It would seem that less water is necessary. When we look at the chemical formula, six parts water are also produced next to the 6 parts oxygen, and 1 part glucose. However, research has shown that in the chemical process, 12 parts water are needed. The 'excess' water is used in the intermediate steps. The water does not re-appear until the end of the process. CO2 is a gas in the atmosphere. There must always be sufficient carbon dioxide available, otherwise, plant growth will reduce. Everyone knows that plants need water From CO2 and H2O, not only glucose, but also oxygen is made under the influence of light, by the plants with the help of chlorophyll. For plants, Oxygen is a by-product of growth. For people and most animals, it's the primary condition of life. This is a good combination. In fact, in their metabolism, animals do the converse of what plants do. They convert glucose and oxygen into carbon dioxide and water to be able to move, and to allow the heart and lungs to work, etc. CO2, a gas which is exhaled by people, can again be used by plants for photosynthesis. It can be thought of as a cycle. The glucose made by plants is an energy source for the plant. Some processes, such as the intake of water, require energy. Next to that, glucose forms the building material for all kinds of other processes with which the plant lets all its specific properties show. It would go to far beyond the pupose of this book to look into all those chemical processes. For the reader of this book, it's about getting good results growing cannabis at home A plant cannot grow without light, air (which contains CO2), water, and various nutrients. The chemical process in which CO2 and H2O are converted into glucose and oxygen under the influence of light is called photosynthesis. When we look at this process a little closer, it actually involves two different chemical reactions. The first is called photolysis. In photolysis, water is broken down into oxygen (O), and hydrogen (H). Both light and chlorophyll are necessary for photolysis. This is called the light response. The second chemical reaction is called the dark response As the term suggests, no light is necessary for the dark response. With dark response, carbon dioxide is converted into glucose, with the help of the hydrogen produced during the light response. The distinction between the light- and dark reaction is of interest to the cannabis home grower in order to gain insight into the manner in which the plants must be illuminated (and sometimes kept in darkness). The plants grow optimally only when a good balance is found between the light and dark reactions.

Dropper System to water and fertilize marijuana.


2.3. Osmotic processes

With osmosis, we mean the processes in which water and nutrients are absorbed by plants. Osmosis is based on the principle that the plant's walls permit some materials to pass through, and others not. Cell walls are semi-permeable. An example: when we place a bladder with a sugar solution in a tank of water, the bladder swells. The sugar solution attracts the water. The more sugar in the solution in the bladder, the more water will be absorbed, and the pressure in the bladder will rise, but don't try this at home! Among other things, osmosis provides for the sturdiness in plants' cells. So much water is taken in that the plant cells become saturated, and the stalk and the leaves stand upright. If too little water is in supply, the plant cells give off the water; slowly, but surely. The strength is lost, and the plant wiltsAnother way for a plant to lose its sturdiness is for osmosis to work in the reverse direction. If there is too high a concentration of materials in the water fed to the plant, the plant will not absorb water. It will release water, and become less sturdy. An example is the addition of too high a dosage of fertilizer to plants. With over-fertilization, plants dry out and burn . . . A second important function of osmosis is the 'hitch-hiking' of salts (nutrients) together with the water that, through osmosis, ends up in the plant cells. Nutrients are necessary to allow certain growth processes to take place. The salts also cause various kinds of plants to develop various properties. That brings flowers, fruit, and fragrances to mind. In general, plants need the following materials in a water solution: - nitrogen, phosphorus, and sulphur for the construction of cells; - magnesium to manufacture chlorophyll; - potassium, calcium, and magnesium for osmotic processes; - water for growth, for the transport of nutrients, and for sturdiness; - iron, boron, copper, manganese, and zinc as building materials. Most of the nutrients for plants are sufficiently present in our ordinary tap water. But not all The law of minimums plays a great role in the feeding of plants. Material that is present in too small a quantity is a limiting factor on the plant's health. So-called 'deficiency disease' appears when a plant does not receive one or more nutrients. For example, a shortage of iron causes rather white leaves, while a shortage of nitrogen causes reduced growth and yellowed leaves. 'deficiency disease' involves not only the direct effect (an unhealthy plant doesn't grow well), but also impaired resistance. If needed materials are lacking, the chance for infection by moulds and vermin increases. We will discuss plant diseases more extensively in a later chapter. In order to raise healthy plants, we need further amplification of the materials which, by nature, appear in our water. This involves primarily nitrogen (N), phosphate (P), and potassium (K). A formulated combination of these materials is available in shops, and is called 'NPK solution'. We differentiate the different nutrients in order of importance. We call the most important the primary nutrients; - the NPK combination just mentioned. The secondary nutrients follow; namely magnesium (Mg), and calcium (Ca). Finally, there is a group of micro-nutrients, also called trace elements. Sulphur (S), iron (Fe), manganese (Ma), boron (B), zinc (Zn), and copper (Cu) belong to this group, among others.

Over fertilized marijuana plant

overfertilized plant

2.4. Intake and transport of materials

Water, and the nutrients dissolved in it (salts), is absorbed through the root hairs of the plant. The condition of the soil plays an important role. Hard dirt allows little space for water to reach the root hairs, a looser soil has much more space, while rockwool substrate can guarantee a good water supply. Root hairs are very important. When they don't work well, the plant receives too little water and food. Growth is retarded. Root hairs are very sensitive; they can easily be damaged by exposure to air and light. Moreover, you can ruin them by careless transplanting, or just by exposure. The intake of water and nutrients requires energy from the plant, so oxygen and glucose are necessary. Ultimately, temperature is a limiting factor. Even if you take care to provide sufficient water and nutrients, the growth of the plant will be impeded if the ground temperature is too low. This is one of the reasons why most plants outside grow very slowly during the winter. The transport of water and nutrients insures that these materials end up in the leaves. Two forces are responsible for this: the suction power of the leaves, (they lose moisture by evaporation, causing suc-tion to occur), and so-called root pressure. Root pressure can be observed when we cut off a branch of a tree in the spring. Moisture comes from the 'wound', and we call this the plant's sap. The suction force of the leaves depends on the evaporation of water through the leaves. Stomata are responsible for this evaporation process. The stomata can open and close. Next to the evaporation of water, they provide principally for the intake of carbon dioxide (CO2) from the air. They also issue the oxygen which is produced. In the previous paragraph, we have seen that plants lose their sturdiness if they lose too much water. The stomata dispose of a mechanism to prevent that: they can close. Generally, a stoma will be open if there is light, (thus providing for CO2 intake, and for optimal suction power of the leaves), and closed if it's dark (when no CO2-intake, or evaporation is necessary). If the air is extremely dry (dry, hot, mid-summer days!), the stomata can also close during the day. For stomata to work properly, a clean surroundings is necessary, since a stoma can become blocked with dirt particles. Sufficient potassium (nutrients!) are also needed.

2.5. Factors influencing the growth of plants

We conclude this chapter with a summ-up of the principal concerns for the optimal growth and flowering of plants. The following factors are the most important ones: - the correct temperature; - the correct CO2 content in the air; - the correct light intensity, with the correct wavelength of the light; -the correct amount of water and nutrients - the right soil; - (for cannabis growers) the right seeds or cuttings/clones; - 'green fingers' In the second part of this book, we discuss which materials you need for growing at home. We take a deeper look into the different factors which influence growth and flowering. Summing up this comes down to an optimal control of climate.

Complete rockwool set.Greenhouses full of marijuana.

complete 2m2set

PART II: Necessities and Climate Control

Chapter 3: Necessities and Basic Installations

3.1. Preface

In this chapter, everything necessary for home-growing is discussed. After describing the conditions required for your grow room, we pay some attention to the materials you need to get started. Two things are always important: proper climate control, and complete safety. Growing plants indoors roughly involves three things: light, air, and water. After listing the necessary materials and equipment, we reveal the most important aspects about how you can achieve the best results.

3.2. The grow room

The first requirement for a grow room is that it must enable you to know how best to control the temperature, air circulation, and humidity. In any case, for good climate control, it is necessary prevent draught. For this reasons, a garage or a shed are often less suitable. If you see possibilities to make a garage or shed free of draught, then, of course, there is no objection. The grow room must be completely screened off. Make sure that everything not directly involved with growing is removed. That way, you prevent the chance for moulds and insects as much as possible. In fact, the grow room should be just as sterile as the operating room in a hospital You can only expect optimum climate control if the room is totally sealed. In practice, that means taping up windows and don't forget aal the gaps and narrow openings around doors and windows . In some cases, it is advisable to place a wall as a screen between the other activities in a room. When growing under artificial light, it is important that the walls of the grow room absorb as little light as possible. Experiments have proved that flat-white paint has the best light-reflecting properties. So, cover the walls of the grow room with matt white paint. This will maximize the light-yield per lamp. The space must also be arranged in such way that everything is within reach. That means you have to have room to walk around the tanks or tables where you're growing. It also means leaving enough space to take care of your lamps, and be able to water all the plants. A garden measuring 3x3 meters needs 200 liters of water per week, or more. All that water is not absorbed by the plants' roots, thus a drainage system is needed. The floor must be a smooth material; concrete is ideal. With other kinds of floor surfaces, it is advisable to use (white) vinyl or linoleum. Also consider an upright brim, so that water cannot leak to lower stories of the building. Finally, it's handy to have a place to store the tools you're using. A small cupboard (painted matt white!) in the grow room is best. There's another reason to work in a well-sealed grow room: your activities should not be seen. Also, make sure that the bright lights you'll be using aren't visible from outside.

Inlet and outlet boxInlet air system


3.3. The shopping list

You don't need a lot of equippement to grow cannabis on a (very) small scale. A grow tank, soil, nutrients, enough light, and an agreeable temperature make growing hemp indoors quite possible A good alternative for growing in soil is to fill planting pots with lava stone granules, or with rockwool flakes. In order to achieve a smooth growth- and floweringprocess you must pay a lot of attention to ventilation, regular watering, proper lighting, etc. Without appliances, you have to care for the plants every day. Therefore, you have to choose between growing in soil or in rockwool. Working on rockwool is advantageous because you don't have to drag bags of soil around Still, some weed growers swear by soil, because they think the quality of weed isn't as good if you grow on rockwool. Others see no difference. They would rather grow on rockwool, because they can achieve a greater yield. There are, however, many factors which affect the healthy growth and flowering of cannabis. 'Green fingers' are certainly not the least important We've made a shopping list for (semi-) professional growing on rockwool substrate. Cheaper alternatives can be devised for many of the articles. We'll return to the three aspects light, air, and water later in greater detail. The materials listed below will cost between 2250, and 3000 guilders for a grow space slightly larger than two square meters:

- 3 armatures for high-pressure gas lamps;
- relay box for the lamps;
- 12 libra trays with water drainage;
- 12 rockwool slabs;
- 36 rockwool blocks 7.5 x 7.5 x 6.5 cm;
- irrigation system with an immersible pump, electric timer clock, water reser voir, air pump, heating element
- ventilator for the intake and outlet of fresh air and the discharge of humidity;
- measuring cups (100 and 500 ml);
- hygrometer;
- pH meter;
- EC meter;
- thermometer with indications for minimum- and maximum temperatures;
- fertilizers;
- saltpeter/phosphoric acid.

Unfortunately, you're still not ready, even with the materials listed above. Optimum climate control is needed for growing indoors. A ventilation system can (and in some cases, must) be added; varying from a simple bathroom ventilator to a more expensive carbon dioxide box ventilator with a humidifying system. You can go for a larger-scale approach by providing a system to keep the CO2 content optimal, by installing air-conditioning, or your own water purification regulated by osmotic filters, or by using a computer to regulate feeding. You can easily spend more than 20,000 guilders for a complete home-grow system if you want .

CO2 computer.

CO2 computer for cannabisComputer flow unit for cannabis.


3.4. Grow room layout

First, the lamps are installed. It's important to ensure enough power capacity. The three lamps together require 1200 watts of power, while the pump and the ventilator also draw current. The safest manner is to allow a separate circuit in your tool cabinet. With a 16-ampere circuit, you have 2800 watts at your disposal. The circuit does provide more power than that, but you cannot use it all. When the lamps are turned on, they use more power than the 400 to 600 watts they give off. Too high a current drain will blow the fuse The lamps must be distributed so that the entire growing surface will be evenly illuminated.

Lamp or light height for marijuana plants.lampheight

It's a good idea to build a wooden frame to hang the lamps, and to hold the libra-trays. Other devices can be fastened to the frame later. Second, the libra trays are arranged. libra trays are well-suited for growing indoors, because they provide drainage for water run-off. We can also use so-called drainsets. These should be assembled first. When they're assembled, they can be snapped onto the trays. If you don't have access to a drain, it's wise to build a drainage tank. As an alternative to libra trays, you can, of course, use ordinary pots. If you don't want to use drain sets, you can drain water via gutters. The growing trays are filled with rockwool slabs. Holes are cut into the slabs for the rockwool blocks. The blocks are fastened to the slabs with pins. The rockwool blocks are saturated with water and fertilizer. After laying out the irrigation system, the rockwool slabs are then cut on the underside in order to allow excess water to drain. We'll set up the irrigation system. First, make an electrical outlet (earth ground!). The outlet should be conveniently located, right next to the fertilizer tank. We'll put the fertilizer tank just next to, or even underneath, our grow-table(s). The immersible pump is placed in the fertilizer tank to pump the fertilizer to the plants. The pump is turned on and off by a timer switch. This way, we make sure the plants get their water and nutrients on time. A tube is attached to the pump. This tube is connected to a flexible polyethylene hose. This polyethylene hose is suspended over the middle of the libra trays. The end of the hose is sealed with a cap. Punch holes for the sprinklers. The next step is the installation of an air pump with an aerator. The aerator is placed in the nutrient tank so algae won't grow so rapidly. The air bubbles generated by the pump and the aerator take care of that. This way, you also insure that sufficient oxygen gets in the water, and that the fertilizer components remains in motion. Next, put a heating element in the nutrient tank. The element has to maintain the water temperature. To be able to check the temperature, we place a thermometer in the tank. Watering can now begin; the nutrient tank may be filled with water and the proper amount of fertilizer. Pay attention when you mix the fertilizer. Follow the directions on the package accurately. They describe the correct amounts of fertilizer to apply.

Ph and Ec meter for ganja.

Ph and Ecmeter

With too little feeding, the law of minimums comes into play; delayed growth and flowering; unhealthy plants. With over-feeding, the plants will burn . When you apply various kinds of fertilizer (also called A- and B-nutrients), make sure the materials don't make contact with each other. If that happens, then a chemical reaction occurs between the phosphate in the one, and the calcium in the other. Calcium phosphate forms, and the fertilizer loses potency To find out whether or not the fertilizer you're using has the right concentration, we use an EC meter (see the chapter about water). With too low an EC measurement, you should mix in more fertilizer. With too high a reading, you should dilute the solution with more water. In addition, the acidity of the water - the pH value - is important. We measure this with a pH meter (see the chapter on water). When the pH value is too high, we can lower it with saltpetre/phosphoric acid. When the pH value is too low, we can raise it with a solution of calcium carbonate. You must be very careful with concentrated saltpetre/phosphoric acid. It will burn holes in your clothes, and it will seriously burn your skin, too The irrigation system is now ready to be tested. Always make sure the water pump is never turned on in the absence of water. This can burn up the pump's motor. Place a sprinkler in one of the measuring cups and determine how much time it takes to pump approximately 50 cc of water and nutrient into the measuring cup. Program this time into your timer. It's intended that each plant gets around 300 cc water and fertilizer, divided over at least 6 feeding times. If you have a timer which can be switched on and off more often, then you can spread the 300 cc over more feeding times. As an example, we'll consider 6 times. The first 50 cc feeding is given at the moment the lights are turned on, and the last, two hours before the lights are turned off. The other four feedings are neatly divided, via the timer clock, among the periods in between. Plants take in water and nutrients only under the influence of light. This is the reason for giving water and nutrients when the light is on. The last feeding is given approximately two hours before turning the lights off; in order to give the plants the chance to absorb the water before the dark period. The quantities we refer to in this book are average values. The starting point of every grower must ultimately be raising healthy plants. So you also have to have green fingers as you do the watering and feeding
Next month Chapter 4.

Chapter 4: Light

4.1. Preface

Marijuana water tank.

watertank with the needed accesories

Plant growth involves the conversion of light energy into plant-building materials (photosynthesis, see chapter 2). Two factors are important for optimal growth. In the first place, the light intensity. Light intensity is expressed in 'lumens'. At least 50,000 lumens are needed for growing indoors. It's not sufficient to add up the number of lumens listed by the manufacturer for each lamp. The total number of lumens given off is depends strongly upon good reflection, and proper connecting fixtures and starter ballasts for the lamps. The quality of the reflector used, and the connecting fixtures and ballasts determine the light yield for the greatest extent. For those reasons, self-built sets and home-designed illumination often deliver a lot less light yield than lamps being used in professional horticulture. We can improve the light yield in our grow room by applying reflective material. We haven't painted the walls of the room matt white, and used reflector caps for the lamps for nothing! The second important factor is the wavelength of the light. For the production of chlorophyll, and an optimum photosynthetic reaction, light from the blue spectrum (445 nanometers), and light from the red spectrum (650 nanometers) is necessary. Blue light ensures optimal phototropism. Phototropism is the phenomenon which causes plants to grow towards the light, and to spread their leaves in such a way to receive the most light.

4.2. Choices for lamps

In this book, we prefer high-pressure sodium lamps, and mercury-iodide lamps for illumination. Ordinary light bulbs are not suited for cannabis-growing due to their considerably short life span, and principally due to their low light yield. Halogen lamps are not advisable for the same reasons. Fluorescent lamps are not appropriate for home growing. They do serve well, however, to stimulate seedlings and cuttings to set root. For actual growing, we stick to gas discharge lamps in the form of high-pressure- sodium, and mercury-iodide lamps. There are lamps being sold which emit both the wavelengths needed (blue and red) but we prefer installing seperate lamps in a 1:3 proportion (1 lamp for blue light with 3 for red light). The combination lamps give off a lower amount of lumens, since they have to emit different wavelengths. This counts for growing: the more lumens, the greater the yield. This doesn't mean we can install an unlimited number of lamps. Other factors must be considered. Using many lamps means a higher temperature (the heat must be discharged of), a greater need for fresh air (containing CO2), and a greater need for water and feeding. Always remember the law of minimums Depending on the size of the garden, we use 400 Watt lamps or 600 Watt lamps. This choice is made in such a way that all the plants in the garden area can be illuminated as evenly as possible. By using 400 W lamps, you can put up one-and-a-half times as many lamps for the same electricity use as when using 600 watt lamps.Also 1000 watt lamps are being sold but proper reflectors for these types of lamps are not available. The result is a disproportionately large loss of yield. Moreover, 1000 Watt lamps give off more heat. Therefor they must be hung high above the plants, and this means more loss of light yield plays in the question. 1000 Watt lamps, with respect to 400 and 600 Watt lamps, mostly cause pain in your wallet, because the electricity bill gets higher.
In practice, it is possible to reach a light yield of 70-90% of the lumens which are emitted. For that, (it can't be stressed enough), good reflection is necessary. Below is a chart with data for several reflective materials: Reflectivity in % - Reflective plastic sheet 90-95 - matt white paint 85-90 - semi-matt white paint 75-80 - matt yellow paint 70-80 - Aluminium foil 70-75 - Black paint less than 10 Using proper reflective material, proper connecting fixtures ballast equipment, proper reflector caps with the lamps, and a distance from the lamps to the plants of 40 to 60 centimeters, 400 Watt lamps deliver, on average, between 35,000 and 47,500 lumens, and 600 Watt lamps between 60,000 and 80,000 lumens (at a distance of 50-70 centimeters). The distance between the plants and the lamps differs because 600 W lamps give off more heat. Ifthe plants are to close to the lamps, they will dry out and burn 600 Watt lamps are preferred, because you get the highest light yield for the lowest electricity cost. Though they do require more careful climate control The life span of a high-pressure gas lamp is approximately 2 years when it's used 18 hours a day. The lamps are, however, subject to decay, which lessens the light yield.

Communicating marijuana vessels

communicating vessels

In practice, it appears that high-pressure gas lamps give optimal results for 4 to 5 harvests. After those, it's advisable to replace them. It seems that the installation of one 600 Watt sodium lamp per square meter is enough to achieve the best results. Principally one can say 'the more light, the better', but with more illumination, the control of other factors (namely, temperature control) becomes a problem. Indoor growers work with their light source close to the plants. Considering the light yield of the sun, (hundreds of thousands of lumens, but a little further away), fewer lumens are needed for growing indoors. A simple formula shows that you can also use three 400 W lamps for two square meters. The sodium lamps provide light from the red spectrum. This light is used principally during growth. A mercury-iodide lamp fills in the blue spectrum. For reflection, growers use wide-angle reflectors with sodium lamps, and super-wide-angle reflectors with mercury-iodide lamps. Super-wide-angle reflectors spread the light over a greater surface area. We use the proportions of 3 red lights to 1 blue. So, the light from the blue lamp must be spread over a larger surface area.

4.3. Using high-pressure gas lamps

High-pressure gas lamps may only be used in the fitting meant for that particular lamp type. High-pressure gas lamps all have their own start-up conditions, voltages, characteristics, and shapes. Using lamps with improper sockets can cause electrical shorts! Therefore, it's recommended that you buy all the parts of a pressurized gas lamp from the same dis- tributor. The sockets, ballasts, and connectors must always be protected from humidity; otherwise, electrical shorts occur. As stated earlier, high-pressure gas lamps have a long life span. You must be careful when replacing these lamps. They are, as the name implies, under pressure, and they explode when you destroy them. When you do that yourself, you must always wear gloves and safety glasses. In addition, you have to protect yourself against the poisonous materials found in these kinds of lamps. The heat given off by high-pressure gas lamps, and their accompanying starter ballasts, must be completely ventilated. This means that the lamps shouldn't hang too close to the plants (hence drying and burning occurs), but also not too close to (flammable) ceilings and walls. Place a piece of non-flammable material (not asbestos!) between the lamp and ceiling or wall. Furthermore t's necessary to discharge of excess heat by using a ventilator. Finally, it's important to keep high-pressure gas lamps clean. Dirty lamps provide much less light yield than clean ones. The lamps should be polished now and then with some glass- cleaning agent. That should be done only when the lamps are turned off, and well-cooled.

Wear gloves to hanlde marijuana lights.Lamps for germinaing cannabis seedlings.

the use of gloves to protect the lightbulb cloning accessories

Be especially careful with water. Lamps which are still hot, or even warm, can explode when touched, and that's not funny Also, take care never to touch these types of lamps with your fingers. Just like halogen lamps, bodily acids can burn through, causing the lamp to fly to pieces.

4.4. Proper lighting for cannabis

The advantage of growing cannabis indoors is the fact that you can give the plants the feeling that it's their flowering season all year round. You're not dependent on the weather or the season. We distinguish two separate phases in plant cultivation: the growth- or vegetative phase, and the flowering- or generative phase. We've already made sure the lamps are installed in such a way that all the plants can be optimally illuminated. A light period of 18 hours and a dark period of 6 hours is ideal for the vegetative phase. We're assuming that you already have cuttings with roots. With proper care, a healthy cannabis plant can grow up to 5 centimeters per day. It's very easy to cause the plant to flower. We only have to give the plants the idea that the days are getting shorter ('autumn'; for cannabis, the sign to flower). We do that by making the light and the dark periods the same length; - 12 hours. In principle, cannabis is an annual plant. The entire life cycle, from seed to death, takes place in one year in nature. When growing cannabis under artificial light, it is possible to force flowering earlier than in nature. After 4 or 5 days vegetative phase, flowering can be 'provoked'. We do that the moment the clones have visibly started to grow. Two or three weeks after the light period is reduced to 12 hours, the plants begin to flower. It's very important not to interrupt the dark period. If the plants receive light during the 12-hour dark period, they 'get confused'; they want to continue growing, and the blooming phase is postponed. The generative phase lasts 60 days or longer, depending on the variety you're growing. When working with cuttings, it's possible to harvest four to five times a year.

Clipping of clone

the cutting or clipping of a clone and the motherplant and its clone on a rockwool plug

Chapter 5: Light

5.1. Preface

Almost all living beings are dependent on light of satisfactory quality. For humans, that means that sufficient oxygen must be present in the air, and that the air is not too polluted. For plants, and thus also for cannabis, it means good air quality, enough carbon dioxide (CO2), and not to much pollution. Relative humidity (RH), and temperature also play a large role in the growth of plants.

5.2. Influencing air quality

The amount of CO2 in the open air is appoximately 0.03 to 0,04%. The amount of carbon dioxide is also expressed in parts per million; ppm. 0.03% is equal to 300 ppm. There are differences in the CO2 needs among plants. By raising the CO2 content, growth can be accelerated. The law of diminished returns still holds true, however. Raising the CO2 level has limits, but at approximately 1400 ppm (0.14%), good results (a faster growth) are generally achieved. Above 1400 ppm, the effect of a higher percentage of CO2 decreases. A high concentration of CO2 is poisonous even for plants. A CO2 concentration of 1800 ppm or more is deadly for most plants. A simple method for guaranteeing the supply of carbon dioxide is to ventilate the room. Sufficient ventilation must be provided, so the plants keep getting enough fresh CO2. A second and just as important reason for ventilation, is to dispose of excess heat. If the temperature gets too high, (see Section 5.4), growth is stunted. This counts not only for the temperature in the grow room, but also for the temperature in the plant itself. When the plant's temperature is too high (humans get a fever), there is less sap flow, causing growth distubances. There is no standard solution for refreshing the air. The need for fresh air is, for a large part, dependent on the size of the grow room in cubic meters. In principal, the total air content of the room must be exchanged every 2-3 minutes. Using for example a grow room 3 meters long, 2 meters wide, and 2 meters high (12m3), this means that the ventilator capacity must amount to 30 x 12 = 360 m3 per hour. A standard bathroom ventilator can only handle up to 100 m3 per hour Many growers ventilate their rooms with table fans. The point is the control of the temperature as well as the circulation of the air with sufficient carbon dioxide. Table fans are primarily intended to keep people comfortable on a hot summer day. They are much less suited to run continually for heat removal, and for CO2-content maintenance. Table fans have a tendency to melt with intensive use. You can imagine the consequences: not only the danger of fire, but also massive plant death . . . There are, of course, plenty of fans on the market which will take care of proper ventilation. These have been specifically designed to be able to run continually. The CO2 content in the grow room can also be heightened by adding CO2 from a tank. If the system is set with a timer clock, the desired amount of CO2 can be regularly released. Work with care, because you don't know how much CO2 is in the room at any given moment. An overdose can easily occur To prevent this, it's sensible to ventilate the area well before each CO2 'injection'. The most professional option is to use a CO2 controller. This apparatus continually measures the CO2 content in the room. When the programmed minimum value is reached, CO2 is automatically added. If the programmed maximum is exceeded, the controller turns on the ventilating system. If CO2 is added to the room via a tank, or a controller, cultivation can take place at a higher temperature. (More about this aspect in Section 5.4.) Ultimately, attention must be given to the relationship between ventilation, and the relative air humidity. The humidity of the air is dependent, among other things, on the amount of air moved through the room. Changing the air draws more moisture out of the plants, because the stomata release more moisture. If the relative humidity of the air drops too low, the stomata close, delaying the growth process.

5.3. Relative humidity (RH)

The relative humidity of the air influences the functioning of the stomata, among other things. Cannabis flourishes the best with an RH of 60-70%. At higher RH percentages, the stomata have problems getting rid of excess water. At a lower RH, the stoma keep releasing water until the plant dries out. At that moment, the stomata close. Then, the intake of CO2 stagnates, and plant growth is impaired. The relative air humidity is also influenced by the temperature in the growing space. In the chart below, you can see the number of grams of water which can be absorbed in a 25 m3 room (for example: 3 x 3 meters, and 2.5 meters high). Absorption in grams of water (degrees C) 0 degrees 120 10 degrees 240 20 degrees 460 25 degrees 630 30 degrees 840 35 degrees 1120 40 degrees 1460 It may be concluded from this chart, that with every rise of 10 degrees in temperature, the air humidity doubles. Ventilation influences the relative humidity. Ventilating a space makes the RH fall. In some cases it's necessary to install a humidifier in the grow room. The best results can be achieved by using a discharge fan with a variable speed control. This way, you can easily regulate the quantity of air to be removed. When the plants are in the dark, the temperature is lower (the lamps don't give off any heat). So, you would expect the relative humidity to fall (less moisture can be absorbed by the air). But this is not the case; RH increases in the dark. The plants breathe out water in darkness. Therefore, sufficient ventilation must be provided. Too high a humidity level provides considerable risks for the health of the plants. Generally, pests and diseases (see Chapter 8) have a better chance with a high humidity level. Too low an RH is also risky; the plants can easily dry out. Prevention is better than cure . . . Finally, it should be stated that young seedlings and clones generally perform better at a humidity level of 65-70%. Their root systems are not yet developed well enough to take in water fast enough. A higher humidity insures that the young plants will be protected from drying out.

5.4. Temperature

The high-pressure gas lamps we use for cultivation cause a considerable amount of heat in our closed-off grow space. This heat can be damaging to the plants. In the first place, we have to make sure the plants are not too close to the lamps. A distance of approximately 40 centimeters (for 400 Watt lamps), or 50 centimeters (for 600 Watt lamps) is good. The lamps also warm the air in the room. This heat must be discharged via the ventilation system. Cannabis seems to grow best at a temperature of 25 to 26 degrees Celsius. This temperature must not be allowed to rise any higher in grow rooms where no CO2 enrichment takes place. When working with bottled CO2, or even a CO2 controller, the temperature can be a little higher; 27 to 29 degrees. When working at higher temperatures, the RH must be closely monitored. Every 10 degree rise in temperature means that the absorption capacity of the air nearly doubles (see Section 5.3). In the dark period, the temperature may drop a little, but not too much. If the temperature is too low during the dark period, moulds have a better chance A temperature of approximately 20 degrees Celsius is ideal for darkness. In order to maintain an optimal temperature, you need a discharge ventilator. The discharge ventilator has a double function: refreshing the air, and drawing off the heat. As described earlier, the capacity has to be great enough to replenish the air content of the grow room at least thirty times every hour. Accordingly, when working at higher temperatures (by adding CO2), the plant needs more water and more feeding. Remember the law of minimums. We can raise the CO2 supply, but if we don't give extra water and extra fertilizer, plant growth adapts itself to the aspect of poor care.

Chapter 6: Water

6.1. Preface

With the short description of plant physiology, we already looked into the function of water in plants. Water has three functions: it is a building material (together with CO2 and light energy, glucose is produced), it makes the plant sturdy (the plant cells fill themselves with water, giving the plant a firm structure), and it transports nutrients throughout the plant. Water is indispensable for the existence of plants. Remember that the law of minimums plays a crucial role here also: too little water, but sufficient light, CO2, and nutrients, produces unfit plants. Too much water, with respect to the other criteria, produces just as poor results. Therefore it's important to find an optimal balance, so the plants will flourish.

6.2. Water quality

It probably goes without saying, but the water you use must be as clean as possible. For plants, however, 'clean' is a relative concept. Nutrients such as nitrogen, phosphate, potassium, etc. are always dissolved in water used for plant food. In any case, the concentrations the plants need of these materials make the water undrinkable for humans. In contrast to 100% distilled water, 'pollutants' are found in ordinary tap water. You can request a chart with data about the quality from the company that produces your drinking water. The hardness in degrees - the GH (German Hardness) - is also given. This is a measure for the amount of calcium in the water. Below, you have an example of this kind of water chart. Some of the 'pollutants' aren't 'pollutants' to plants, but actually fertilizing materials. To determine the water quality (and the plant foods you add), you need two types of meters. The first is an EC meter. 'EC' is the abbreviation for 'Electrical Conductivity'. Pure water, also called demineralized water, does not conduct electricity. When we add fertilizer to the water, or the water is 'polluted' in some other way, the water will indeed conduct electricity. Fortunately, home growers can make use of this property of water. With the EC meter, we can determine whether or not the concentration of nutrients in the water will provide for optimum plant growth. A high EC value means a high concentration of fertilizing materials, and a low EC value, a low concentration. Too high a concentration shows that you're over-fertilizing. As a result, your plants will dry out and burn. (By osmotic processes, water is drawn out of the plant; the leaves curl upwards or downwards.) The fertilizer concentration must be lowered by further diluting with water. Too low an EC value means a shortage of fertilizer. This decreases the growth on rockwool substrate. The EC value is given in millisiemens. 1.8 millisiemens is the optimal value for growing cannabis. The second type of meter is the pH meter. With a pH meter, you can determine the acidity of water. Most of us have measured the acidity of a solution at one time or another in high school. We did it with a litmus test. But the litmus test is not suitable for measuring acidity when growing hemp at home. The accuracy of this test leaves something to be desired. Actually, we can only estimate the pH value, to the accuracy of one pH point. We need greater accuracy for cultivating cannabis. The average pH meter used by aquarium owners is relatively cheap, and meets the requirements well. Generally, they're up to 0.02 pH points accurate. The ability to absorb nutrients depends on the acidity of the water. If the pH is too high or too low, the plants can't absorb some nutrients properly. Then deficiency disease occurs . The pH scale goes from 1 to 14. A solution with a pH between 1 and 7 is called 'acid', a pH of 7 is called neutral, and between 7 and 14, 'basic'. The lower the pH, the more acidic the solution (in our case: water). On the next page, you have a chart showing which nutrients plants can absorb best at each pH. You can read from the chart that cannabis plants like it if they receive water which is slightly acidic. The home grower must make sure that the pH of the water being used is approximately 5.8. The EC meter, as well as the pH meter, must be adjusted now and then. Special calibrating fluids are available for this operation. The temperature is also an important factor when calibrating an EC meter. The correct temperature is listed on the package of calibrating fluid. A pH meter has two set screws, and it must be adjusted to two values. The probe of the pH meter is first dipped into a calibrating fluid with a pH value of 7.0. Then, this value is set using one of the set screws. After that, the probe must be cleaned well; otherwise, deviations will occur with the second calibration. Next, the probe is dipped in a calibrating fluid with a pH value of 4.0, and this value is set using the other set screw. It's important that the pH meter probe is kept moist. Depending on the type of pH meter, it may be stored in ordinary tap water, or in a special fluid supplied by the manufacturer. In the story about the EC meter, we've already indicated that the temperature of the nutrient solution influences plant growth. Cannabis grows best with a water temperature of 25 degrees Celsius. Below this temperature, the roots of the plant have more trouble taking up water and nutrients. Too high a temperature is not good either. That will kill the plants Tap water must be warmed up to 25 degrees C. Use a water thermometer to keep an eye on the water temperature. Warming the water is easy with the installation of a heating element in the nutrient tank. This equipment also comes from the aquarium world. Quality heating elements with thermostats are available for aquariums. For a 100 liter nutrient tank, you need a 100 Watt heating element; with a 200 liter tank, we recommend a 250 Watt element. Make sure the heating element is always kept under water; otherwise it will be destroyed. This means that you must never pump all the water out of the nutrient tank to the plants. When you want to take the heating element out of the water, always disconnect it first. Then, let it cool off for at least 15 minutes. Only then can you carefully take it out of the water. Any other way, you run the risk the element will crack. To prevent algae growth in the nutrient tank, it's important to add air to the water. We do that by means of an aquarium pump with an aerator attached. The aerator is connected to the pump, and placed at the bottom of the nutrient tank. The water in the tank becomes rich in oxygen by aeration, and is also kept in motion. This way, algae have much less chance to proliferate.

6.3. The irrigation system

We do everything we can to promote plant growth. We provide optimal lighting and sufficient CO2. As a third component, regular irrigation is an essential link. This way the plants receive their water and nutrients in time. The easiest way is to water by hand several times a day. But, in the first place, that involves carrying a lot of watering cans around, in which you've dissolved the correct amount of fertilizer every time. In the second place, watering by hand requires enormous discipline. Giving water regularly on time will quickly 'water' YOU down You can't skip a few days here and there, and leave your plants to themselves. Finding a babysitter for cannabis plants is often more difficult than finding a babysitter for your kids . . . So, we prefer to give water regularly with an irrigation system controlled by a timer clock. This way, we can rest assured the plants get their wet and dry periods on time. In Chapter 3, we've given a lot of attention to the installation of an irrigation system. Now, we'll go a little deeper. In its simplest form, an irrigation system consists of an immersible pump, controlled by a timer clock, which has hoses with sprinklers attached to it. The sump pump is placed in a nutrient tank with a capacity large enough to make refilling necessary only two times per week. We're talking about a tank with a contents of at least 25 liters per square meter of garden space. 5 to 7 liters of water with nutrients are used every day for each square meter. So, refilling the tank every 3 or 4 days is enough. Remember, there must always be enough water in the tank to cover the heating element and the pump. Both instruments will be ruined if they are left without water Preferably, the nutrient tank should sit on the floor. There are two important reasons for this. In the first place, it saves space. The tank can also be underneath the tables. In the second place, it prevents the natural working regarding water levels between communicating vessels. If the nutrient tank is placed too high, the water will flow through the hose without the aid of a pump. This goes on until the water level in the tank reaches the same level as the lowest point of the connected irrigation hose. Solutions can be devised for the problem of 'communicating' vessels; - coupling an electric faucet between the nutrient tank and the irrigation hose, for example. This solution is unnecessarily expensive. The problem of communicating vessels can be prevented by placing a sprinkler outlet on the top of the hose. The sump pump must be powerful enough to send water to all the sprinklers that will be installed. For a garden 2 to 10 m2 in size an immersible pump with performance capability of 7 meters is enough, if used with a 1-inch irrigation hose. Also, the pressure of the pump should not be too high, otherwise the sprinklers (also called capillaries) won't drip, but spray Most sprinklers function at a pressure from 0.5 bar on up. To the immersible pump, we connect an irrigation hose (polyethylene or PE- hose). The irrigation hose goes through the middle of the grow trays. Then we make holes in the polyethylene hose and insert the sprinklers. We install one sprinkler for every plant. We have to prevent dirt and other materials from clogging up the narrow openings of the sprinklers. We take two measures: first, we keep a lid on the nutrienttank so nothing undesirable falls in the water. Second, we place a filter between the pump and the irrigation hose. In an ideal situation, plants should get water and nutrients spread evenly throughout the day. We can arrange for this by connecting a timer clock to the irrigation system. A suitable timer clock must also have a minute setting, and must be able to switch on and off at least 6 times a day. Modern timer clocks are digital. These clocks have a memory to store the desired times. If the electricity goes off, batteries usually supply current to preserve the memory. The disadvantage is that batteries run down. If the battery is dead, and the electricity goes off, the memory is erased. The steady watering stops, and the garden is damaged. The recommended choice is a timer clock with a good car battery for backup. Now, our irrigation system ensures that the plants get the correct amount of water and fertilizer on time. The sprinklers evenly distribute the nutrient solution. We prefer growing in 'libra trays'; - so-called 'growing trays' which have been especially designed for growing on rockwool slabs. There are other methods, of course. You can also lay rockwool slabs on corrugated roofing sheets, for example. This does give problems with drainage water . It's more hygienic, and more practical to work with growing trays. They're not expensive, and it's simple to connect a drainage system to them. Easier still is snapping drainage spouts onto the growing trays. Then the water can be drained into a gutter. We divide the irrigation of the plants into 6 periods during the 18-hour light cycle. The first feeding takes place when the lights are switched on. A feeding session follows every 3 hours, until 3 hours before the lights go off again (the plants can take in nutrients only during the light period!). In the beginning, we don't let the irrigations periods last more than one minute, because otherwise, problems with root development can occur. We stick to short feeding periods. Throughout the entire vegetative phase. During the generative phase (12-hour light cycle), we also divide the 6 feeding sessions so the plants will get water every two hours. Since the plants have grown a little by then, and they need more water, we let the irrigation periods last for two minutes. When irrigating the plants, you must make sure the nutrient solutions soaks through thoroughly. Thorough watering means that about one-third of the water applied drains off. Thorough watering is important to prevent the accumulation of the nutrient salts in the rockwool slabs. If watering is not sufficiently thorough, it's sensible to raise the number of irrigation sessions. Finally, another word about safety. Everyone knows that water and electricity are equally related as water and fire. The sump pump, as well as the thermostatic heating element, work with use electric currency and under water. Use only equipment of wich you are sure it is well-insulated. Moreover, it's sensible to disconnect the plugs before you put your hands in the nutrient tank. This can save you from a possibly shocking experience

PART III: Growing Cannabis

Chapter 7: Clones and Cuttings

7.1. Preface

In the previous chapter, we've told you what equippment you need to grow hemp. Furthermore you've been initiated into the secrets of good climate control to reach an optimal result. Up until now, we haven't said a word about the living material you can use to 'rise high'(!) . . . In this chapter, we'll look at the actual cultivation. We'll leave sprouting cannabis from seed for what it is. We'll talk about starting with clones. It's not completely clear why the word 'clones' has been adopted by the weed grower; we're talking, in fact, about 'cuttings'.

7.2. Cloning hemp

Cloning hemp is a cheap, quick way to get plants. The average gardener has taken cuttings from his/her house plants at one time or another. It's not much different with hemp. We only have to make sure the carefully removed cuttings from the mother plant are brought to root. A healthy mother plant can pass on her THC-producing properties from generation to generation by means of cuttings. Each cutting has the same properties as the mother plant. A cutting can be taken from a cutting. And from that cutting, yet another. There are growers who have raised 20 generations from a mother plant this way, without diminishing the growing power of the plants. The yield from the 20th generation is just as good as the yield from the first one! By then, the original mother plant is long past use. Taking cuttings causes trauma to a plant. The plant reacts by taking on a deviant form, and by starting male branches. A third problem is regressive mutation. The mother plant has been developed by cross breeding. With regressive mutation, the carefully bred properties (to a degree) are lost. The quality of the plant (and, of course, the quality of the harvest!) decreases. For this reason, we replace the original plant with one of her fresh, healthy daughters after 12 weeks at maximum. The ease with which hemp can be cloned makes planting cannabis seed less attractive. In the first place, sowing seed takes a lot more time than growing from clones. An advantage not to be underestimated is the fact that you can harvest much more often if you raise clones rather than grow from seed. On top of that, you get males as well as female plants from seed. The chance that a seed produces a male plant is just as great as the chance a female will appear: 50% . . . To make hemp cuttings/clones we need: - a high-quality mother plant; - sharp scissors, or a sharp knife; - any commercial hormone mixture to promote root growth; - something to start the cuttings in (a cutting tray with rockwool plugs, a small grow-tank with washed, rough sand, fine vermiculite, a soil-free mixture, or potting soil); - phosphoric acid - a 'cool white 33' fluorescent tubelight with the proper armature; - ventilation; - clean working methods, and clean sur roundings; - 'green fingers' In contrast to raising cannabis plants, for which we use 400 Watt or 600 Watt high-pressure gas lamps, clones develop their roots best under fluorescent light. Fluorescent tubes emit light primarily in the blue spectrum. Controlling the temperature when using fluorescent lights is also less complicated, because fluorescent tubes give off little heat. The fluorescent tube armature is mounted approximately 25 cm above the tops of the clones. We're going to illuminate the cuttings 18 or 24 hours per day. We keep the light on 24 hours a day during the cold months. The illumination times suggested here are a guide. What it actually involves is allowing the climatological conditions to vary as little as possible. You get the best results with an even climate. It requires some experience to create the optimum conditions . . . The hemp cuttings form their roots best at a temperature of 25 to 26 degrees Celsius, and a relative air humidity of 70-75%. Just as is the case with actual growing, climate control is very important for cuttings. Moulds and pests insects must never get a chance. Above all, mould spores can cause problems if the climatic conditions aren't optimal. In principle, every part of a hemp plant is suitable to use as a cutting. But a single leaf with a few roots is of no use of course In any case, a good cutting has a growth-point. The size of the cutting doesn't matter so much; a 2 cm cutting can grow to be a top-quality plant, just like a 10 cm cutting. Before you put the cutting in the growth medium, you have to make preparations. We're talking about raising cuttings in rockwool substrate. First, the growing tray should be soaked in a nutrient solution. The pH value must be 5.8, the EC value 0.8 to 1.0. To reach a pH value of 5.8, you best use phosphoric acid. The advantage of phosphoric acid is that it helps the cuttings develop roots. We fill the tray for the cuttings with the nutrient solution and drain it off again. We do this several hours before taking cuttings from the mother plant. The cuttings are clipped, or cut with a sharp knife or scissors. Take care not to leave the ends frayed. A clean cutting loses less sap than a cutting with a frayed end. Moreover, there's the risk that ravelled parts of the plant will rot. Directly after clipping or cutting, we dip the clone first in water, and then in rooting hormones. Then we stick the cutting into the rockwool plug. The growing tray for the cuttings must then be saturated for 3 or 4 days with nutrient solution. Good hygiene is very important when getting cannabis cuttings to root. Work as clean as possible. Always clean your scissors, knife and growing trays with a medical disinfectant (i.e. Dettol) after you've used them. Check the clones daily for possible rotting parts. Rotting leaves or stems must always be removed, so that moulds won't get a chance. It's also important not to put the clone tray in a bed of water. That makes rooting more troublesome, and the roots will be of less quality. Also, a too wet clone tray causes root rots such as pythium afungus on the roots. Just like all plants, hemp cuttings also need fresh air containing CO2. We have to ventilate the clone room, too. Sometimes, ventilation is necessary to keep the temperature stable. When using a ventilator, you must try to create an optimal climate without exposing the plants to gale force 9. The cuttings can dry out as a consequence of too much air movement. When you have all the climatic conditions under control, you can start waiting for roots to develop. It takes about 10 days before you see the first results with healthy plants. After a fortnight, healthy cuttings will have enough roots to be transplanted. In principal, approximately 80% of the cuttings will root, if you control the climate well. Allow the cuttings which have no roots after a fortnight one more week. These cuttings can produce a plant of lesser quality. If no roots have grown after 3 weeks, you can throw those cuttings away. Don't count on all the cuttings taking root; plant about 20% more than you ultimately intend to keep. Planting rooted clones is a tedious job. The root systems of the young plants are very tender, and can easily be damaged. The extremely small root hairs are very important for a healthy plant. Many splendid cuttings have been ruined by rough transplanting The roots of plants don't like light (they grow in the dark), and air (they dry out quickly). The young plants will now go to the spot where they will spend the rest of their lives. For plants, transplanting more than once is just as traumatic as making people move house twice a month . . . Now, the plants must become accustomed to their new surroundings. They must get sufficient water, but not yet the full amount of light. After a few days, the real irrigation schedule can begin, and the plants go under the full light of the high-pressure gas lamps. The vegetative, or growth phase begins . . .

7.3. The vegetative phase

In this phase, the plants are illuminated 18 hours per day, and kept in darkness 6 hours per day. If all aspects are in order, (sufficient light, proper ventilation, good temperature, enough water and nutrients, in short: complete climate control), the plants will grow quickly; up to 5 cm per day. The duration of the vegetative stage is strongly dependent on the control of climate. The better the climatic conditions, the earlier the cutting takes root. The vegetative phase lasts from 3 to 10 days at maximum. We'll discuss growing 15 plants per square meter. If we want to use the surface area to the maximum, then we must prune the plants; - break off the uppermost part. pruning is possible only with plants that have rooted and begun to grow. If this is not the case, breaking or clipping the tops off should be postponed for a couple of days. By pruning the plants, we ensure that they not only grow tall, but wide, as well. After cutting off the tops, we leave the plant in the vegetative stage (18-hour cycle) for a few more days. When the off-shoots have grown 3-4 cm, we start the generative phase. If all goes well, three or four large tops will then form on each plant. Then we're ready to get around 50 tops per square meter. To get a wider plant, you can now break off the top-most part of the plant. Further pruning is not necessary. Pruning makes the plant grow fuller. That's not to say you get a bigger plant, because you've also taken something away . Since the vegetative phase lasts only a short time, the plant must quickly make up for the damage. After pruning the top, two new branches will appear from the budding sight just under the spot where the top was. Be very careful with pruning; it's a more painful experience for a plant than trimming your own nails After pruning, it's not unlikely for growth to be delayed for a few days. It needs no further explanation that a clean, razor-sharp knife or garden scissors should be used. Actually, we can only think of one good reason for pruning. When branches don't grow well, or are sickly or too thin, in short; unhealthy, you can, of course, carefully remove them. With pruning, it always involves the removal of the whole branch. Take care to touch the leaves as little as possible. That can easily disturb the workings of the stomata in the leaves. Some people swear by removing leaves in order to allow more light to reach other leaves. This is necessary; moreover, part of the growth capacity is lost. It's also unnecessary to remove dying leaves. You only have to clear these away after they've fallen off the plant. Picking them off earlier might again cause damage to the plant . . .

7.4. The generative phase

After one weekat maximum, we will shorten the illumination time, and adapt the irrigation schedule accordingly. We keep giving water 6 times per light cycle. Give water and fertilizer during the period that the light is on, and not during the dark period. In the flowering, or generative phase, the plants are in the light for 12 hours, and in darkness for 12 hours. We imitate a shortening of the day in autumn; a sign for the plant to start flowering and forming seeds during its last phase of life. In the generative phase, the plant's emphasis is less on growth. Less chlorophyll is produced and in the flowering phase, we often see fewer fingers forming on the cannabis leaf. The plant needs less blue light during the flowering phase (that was important for chlorophyll production in the leaves), and it needs more red light. The autumn sun produces more red light, because the autumn sun is lower in the sky.That doesn't mean that you must now use only the sodium lamps. With only red light, the plants lose their vegetative leaves (they turn yellow and fall off easily), while the stem of the plant is lengthened. The distance between the branches (also called the 'internode') increases. When we just let the mercury-iodide lamps supply the plants with blue light, this effect won't occur so easily. The supply of water and nutrients continues. The time between irrigations is shortened, so that the plants are still irrigated during each light cycle. Not in order to push the plants to grow as fast as possible, but to keep the metabolism at level, and to produce resins. The female plants will show their first flowers after a week or two. The following period lasts at least 60 days, depending on the variety. With some of the plants, the blooming period lasts up to 90 days. It's worth the trouble to be patient for the full flowering period before you start harvesting. Harvesting during that time stresses the plants, which can ultimately cause a decreased yield.

7.5. Harvesting and drying

In this book, we assume you've raised female cannabis plants from clones. When you've sprouted male as well as female plants, there will be some work sorting them out. The males flower earlier than the females. If you leave the males with the females, the females will be fertilized. The females then form seed, causing the tops to be smaller. The yield is lower (why did we start growing in the first place?). If you've sprouted males, you have to be sure to harvest them before the pollen reaches the female plants. When you grow only females, you don't have this trouble. There are various methods to harvest cannabis. Some people cut the whole plant down, then hang it up to dry. Others break the largest leaves off several days before harvest, so there will be less waste. Hanging the plants, or the tops, upside down has no effect on the THC content in the tops. The resin doesn't flow. What's important with cannabis is the even drying of the THC-containig parts of the plant. What's also important is patience. Generally, drying goes quicker if you remove the stems which contain the most moisture. Using a microwave, or an ordinary oven, a hair dryer, or a fan does make drying faster, but usually also causes a (much) sharper taste. Even drying in air prevents as much as possible the loss of THC, and produces evenly dried buds with a soft taste. Controlling the climate also remains important after the harvest. Many harvests have been lost due to spider mites and mould. For the THC glands so important to us, light, heat, and friction are the most important things to avoid. Once dried, marijuana can best be kept air-tight in a reasonably cool, dark place. Air-tight glass jars are ideal.

7.6. Skuff

We'll talk about 'skuff'. This is the sifting of dried tops. When you sift your dried harvest first through a rough, then through a fine sieve, you remove all the remaining plant remnants, and get balls of resin (thus; THC) left on the sieve. It's a fairly simple, but time-consuming job. Sift the dried harvest first through a size T-44 sieve. The THC falls through (with a little extra material). We have a T-77 size sieve under the T-44. You must carefully rub your harvest through the T-77 sieve. Then you have THC in it's pure form without chemical processing

7.7. Setting up the garden again

After the harvest, you must make sure you can literally start the following growth with a clean slate. First remove all the leftover plant parts. These go in the trash or in the organic waste, unless you have a compost heap. Then remove all the rockwool material. The rockwool still contains a lot of water.

Chapter 8: Diseases Pests and Plagues

8.1. Preface

Plants are living material. They'll stay healthy if we make sure all the climatological conditions are right. We've already stated earlier that this involves light, air, water, clean surroundings, and green fingers. Controlling the climate, in all its aspects, is the best way to prevent diseases and insects. That doesn't mean that the careful weed grower, who has everything well in order, will never be bothered by plant diseases and pests. We do want to say that good climate control considerably reduces the risks of disease.

8.2. Diseases

An easily preventable form of disease is deficiency- or deprivation illness. The plants lack some necessary ingredient in their feeding. A shortage of iron produces yellowed (and falling) leaves. The pH value plays an important role in the prevention of deficiency disease. Keep the pH value around 5.8. If this value is too low, the plants can't absorb calcium as well. Consequence: the osmotic processes are impeded. Too low a pH number causes less iron in-take, with the well- known results. A second form of deficiency disease is caused by a shortage of the primary nutrients (NPK). It often involves a lack of nitrogen (N). A nitrogen shortage delays growth, and makes the lower-most leaves turn yellow and drop off. Less often, we see a shortage of phosphate (P). With a phosphate shortage, the leaves turn deep green, and they remain small. Yellowing and dying lower leaves happen here, also. Potassium shortage (potassium is 'K') is another seldom-occuring problem. The noticeable feature is first the yellowing of the point of the leaf, after which the whole leaf turns yellow and brown, and dies off. A lack of potassium is more often caused by an acidic soil than by an actual potassium shortage. So, make sure to maintain an optimal pH! The remedy advised for these kinds of deprivation sicknesses: use NPK fertilizer. We don't encounter deficiency disease as a consequence of a shortage of the secondary nutrients very often. This usually involves a lack of magnesium and/or calcium. It can usually be remedied by using an NPK mixture containing trace elements. The same counts for the micro-elements. We must make an exception for iron, since there is rarely too little iron. In that case, the pH value is usually too high. Moulds can completely destroy a garden in a short time. If the climate in the grow room is well-controlled, moulds, in general, have little chance. Moulds and fungi thrive very well under hummid conditions, preferably without much air circulation. Under these circumstances, mould spores, which are always present in the air, search for a spot to grow into mould cultures. If you don't succeed in preventing mould growth, then you must do something about it as quickly as possible. With light mould growth, immediately remove the affected plant parts, and then create a climate in which cannabis does well, and moulds don't (good ventilation, control of humidity and temperature, and putting your plants on a medium which is not too wet). If there's already too much mould present, you don't have much choice but to spray with poison (fungicide). Repeat the treatment after a few days, even if you think the first application has definitely helped. Still,; improve climate control and groth conditions. Fungicide treatment should always be a last resort. It's not healthy for young plants or people, so here, it's also: 'prevention is better than cure' An often-occuring mould affecting cannabis is pythium. This mould causes root-rot, and rot in the lowest part of the stem. It appears most in young plants, and in cuttings. Larger, healthy plants are less sensitive to pythium. Plants get 'falling-over disease' with a serious pythium attack. We don't have to explain what that means Pythium is recognizable by the bark at the base of the stem turning brown. In the beginning, the 'brown attack' is easily removable. Later, the rotting process eats deeper into the base of the plant. Pythium is a fungus which flourishes best in wet and humid environments. Pythium spores spread only through water. Two kinds of spores are formed; Swarming ones and stable ones. The swarming spores germinate best at a temperature of approximately 15 degrees Celsius, while the stable spores germinate if it's relatively warm; around 28 degrees C. To prevent a pythium attack, a constant temperature of the soil or rockwool is needed. Large fluctuations in temperature should be avoided. Pythium can only be fought in a limited manner with chemicals. A proper relative humidity must also be maintained (not too high). Leaf moulds, such as mildew, and thread moulds occur less frequently than pythium. Mildew can cause tops to rot, among other things. Also here counts: ensure optimal climate control. Contrary to other moulds, mildew flourishes well at a low relative humidity. Mildew can be more easily fought with chemicals, and fortunately, is not often found with cannabis. Rotting tops occurs the mainly at the end of the flowering phase. The more compact the plant, the bigger the chance for tops to rot. You can identify toprot by the sudden yellowing of the top-most leaves. These yellow leaves are fairly loose on the plant, and can be easily removed. To prevent the whole plant from being affected, you must, unfortunately, remove the whole top. The appearance of toprot can be prevented in some cases, by lowering the relative humidity during the dark period.

8.3. Plagues and Pests

The most frequently occuring plague in cannabis cultivation is spider mite. A spider mite isn't an insect, as many people think, but actually a tiny spider. A spider mite is small, and difficult to discover for the inexperienced eye. But the damage caused is certainly visible. The mite feeds on the sap of the plant, mostly underneath leaves. White specks appear on the upper side of the leaf. After that, you can find spider mites on the undersides of the leaves, and on the stem of the plant. Spider mites make small webs, which you can detect by spraying with water. If there aren't to many spider mites, you can try to get rid of them by removing them by hand. A tedious job

Treating with insecticide generally gives a better result. In any case, repeat the application after a few days, otherwise, you risk the chance that the whole garden will be eaten. Spider mites can also be controlled with their natural enemy Phytoseiulus persimilis; a predator mite which feeds on spider mites. White flies are also a formidible opponent of the weed grower. It can't be repeated enough: control the climate, and take care of healthy plants. Then, insects will have the least chance to propagate.

White flies behave just like spider mites. The insect hides underneath the leaf, and sucks it's dinner from it. Result: white spots on the top side of the leaf. White flies are easily spotted with the naked eye. If you shake the plant a little, they'll fly around. They look like little white moths, around 2 millimeters in size. A sizeable infestation can be combatted with insecticide. If you're not so anxious to use such strong methods, you can purchase a certain type of 'assassinator' wasp: the ichneumon fly (the Latin name is Encarsia formosa). This natural enemy doesn't sting people, but works well at eliminating white flies. Since it's only a small wasp (smaller than the white fly itself), it takes a while before all the white flies have dis appeared. Additionally, you have to put new assassinator wasps out approximately every two weeks.

Another common herbivore is thrips. They are small, fast-moving insects with wings. They rasp, or grate the leaves open, and then suck the sap out. Thrips prefer bloom tops, and fresh, young leaves. Affected leaves have shiny, silvery spots. This is caused by the thrips, which suck the chlorophyll out of the leaves. In spite of the fact that they're small, you can see thrips marching in columns on an infested plant. Thrips can be fought with insecticide. It's more environmentally friendly however to unleash the thrips' natural enemy: the predator Amblyseius cucumeris. Lice are found inside as well as outside. During the summer, when lice do the best outside, they also do as well inside. Lice are the most interested in plants with questionable health. There are two methods to kill lice: spraying with insecticide, and setting out assassinator wasps. The problem with most flying pest- destroyers is that they're attracted by the high-pressure gas lamps, which draw them to a fiercy death.

8.4. Summary

The starting point for cultivating cannabis is successful climate control. This goes two ways: the plants do well and produce the greatest possible yield, and diseases and pests get the least possible chance. So, create a good climate, and don't forget hygiene If you're bothered by diseases and/or insects, preferably use natural methods of control rather than chemical remedies. You can fight your pests by releasing their natural enemies, or by spraying with organic solutions for diseases and/or pests. Use chemical pesticides only if nothing else works. Always stop using pesticides a few weeks before harvest, otherwise, you'll be smoking some of the poison later. Ultimately, fighting diseases and pests works best only if you know how to optimally control the climate at the same time. Along with climate control, the prevention (and if necessary, curing) of deficiency disease demands an optimal mixture of fertilizers, and the control of the pH.


Absorption power, - of leaves
Air, - intake of water
Air exchange ventilator
Air humidification Air pump Algae growth, - prevention of Amblyseius cucumeris America Bird feed Boccaccio Boron Box ventilator Buyer Calcium Capillaries Carbon dioxide Carbon filter ventilator Cellulose China Chlorophyll Clean-up Climate control, - after harvesting - with regards to diseases and insects CO2, - controller - enrichment and growing tempe rature - necessary for cannabis - raising the content of Combination lamps Communicating vessels Cuttings, - and climate control - and hygiene - illumination period - necessities for - transplanting - waiting time for Cutting tray Dark period, - and relative humidity Dark response Decontamination Deficiency disease, - and the pH value - due to improper feeding - prevention of Diseases Dodoens Drain sets Drain water Drying Dumas Electrical ballast equipment Electrical conductivity (EC), - calibration of EC meter - EC meter - EC value - optimal EC value - optimal EC value for cuttings Encarsia formosa Fertilization, - influence on THC production Floor Fluorescent lamps Flowering period Flowering phase Fungicides Generative phase Glucose Golden Age growing space, - contents of - layout Growth, - principals of Growth phase Growth point of cuttings Halogen lamps Harvesting, - female plants - male plants - methods of Heating element Herodote High-pressure gas lamps, - and safety - cleaning - life of - use of Hugo Illumination period, - in the flowering phase - in the growth phase Immersible pump Insecticides Insect pests Internode Iron Irrigation system, - construction of - testing of - with timer clock Lace -wing flies Ladybugs Lamps, - 1000 Watt - choice of - distance from the plants - light yield - power Law of minimums Law on narcotics Leaf green Libra trays Lice Light, - blue - red - wavelength of Light bulbs Light intensity Light response Magnesium Manganese Matt white paint Medicine, - hemp as Mercury -iodide lamps Moulds, - sprays against Mother plant, - for cuttings Necessities for home growing Netherlands, The NPK, - remedy for deficiency disease Nitrogen Nutrients, - micro - primary - secondary Osmosis Osmotic filter Outside air, - CO2 content in Over-fertilization Paris Polyethylene filter Polyethylene hose pH meter, - calibration of pH value, - for the roots of cuttings - ideal Phosphate Photolysis Photosynthesis Phototropism Phytoseiulus persimilis Plant physiology Potassium Predator Pruning Pythium Rabelais Reflective value Relative humidity, - for cuttings - for the roots of cuttings Remedies, - for diseases and pests Rockwool blocks Root hairs Safety, - and high-pressure gas lamps - and use of electrical power - and water - 'invisible' cultivation Saltpetre/phosphoric acid Salts, - and osmosis Sap flow Semi-professional, - growing Shopping list Sifting Skytes Skuff Sodium lamps Soil -the conditioning of Sowing Spider mite Sprinklers Stomata, - function of - vulnerability of Storing, - of the harvest Sulphur Super-wide -angle reflectors Table fan Temperature, - and air exchange ventilator - for rooting clones - ideal - in the dark period - in the growing space - in the plant - of the ground - of the nutrient water - when calibrating EC and pH meters Thermometer Thrips Timer switch Topping Toprot Trace elements Vegetative phase Ventilation, - and CO2 needs - and relative humidity - capacity - drawing off heat - for rooting clones Ventilation system, - construction of Vinkenoog Water, - functions of - quality of Water purification White flies Wide-angle reflectors Zinc.

the next article doesnt look like it has writing on it but does if u go down like ur trying to copy and paste it it comes up blue and and can see writing

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thanks bud hope it does help a lot of people

admins the article i have put up above the writing isnt showing but like when u go to copy something and it comes up the blue sreen then u can see it could u please see if u could fix it fot me many thanks

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Try to edit it yourself, select all the white text and try to change background colors.

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About us

Strain Hunters is a series of documentaries aimed at informing the general public about the quest for the preservation of the cannabis plant in the form of particularly vulnerable landraces originating in the poorest areas of the planet.

Cannabis, one of the most ancient plants known to man, used in every civilisation all over the world for medicinal and recreational purposes, is facing a very real threat of extinction. One day these plants could be helpful in developing better medications for the sick and the suffering. We feel it is our duty to preserve as many cannabis landraces in our genetic database, and by breeding them into other well-studied medicinal strains for the sole purpose of scientific research.

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