panacea76

Quesion about flushing after 16 days of flowering

22 posts in this topic

Hi,

I've just been watching the super lemon haze (strain hunters grow video)

See here:-

They mentioned that, after 16th day of flowering, you should 'flush' with EC 1.3 then no water for 5 days. Then go back to EC 1.8. Then on day 28 do the same.

But how long do you flush the plant for?

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When you flush you are suppose to put 3x the contenance of your pots in water. so for 11L it would be 30L. but that's a rule, i always say that if you can do 2x it do the job, unless you FLush because of salts or real plant problem there it can be judicious to put 3x, but in your case i think you can go on 2x ;)

Have a good grow

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oh yeah hydro i don't have enough experience to tell you that ^^

Subject has been treated a few times already, try a little search on forum you should find your heaven ;)

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Most information is related to soil. I'm using hydro with clay pebbles..

Advice would be greatly appreciated

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There's very little info in regards to hydro fushing.

Can anyone give me any precise advise please?

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How big is your tanks and how big are the pots???

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In the video the pots are 60L and Arjan and Franco mentioned to flush with the same amount of water, theres no need to flush with a 2x or 3x total pot size rule if not as a final flush before harvest. They are using rockwool flakes as medium in a drain-to-waste method.

For the wilma you can flush for 24h or in this case you can go for 12h.

Take care

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Posted 05 January 2012 - 02:32 PM

Originally posted by Franco in - ghsc 3 flush technique in Hydroponics

FRANCO'S TRICKS ON: FLUSHING THE MEDIUM

Most growers use synthetic feeding to grow cannabis. This is mostly because synthetic feedings are ready-to-absorb, work fast, and are easy-to-dose. Nevertheless, compared to organics, there is one single main disadvantage: salt buildup in the medium. As a consequence, flushing the medium where cannabis grows should be seen as a natural, logical, unavoidable step to maintain a healthy, productive crop. A clean growroom, and clean tools, are just the beginning. It is also important to keep clean the environment where the roots grow, the medium. Roots develop in a dark, wet environment and are prone to absorb fertilizer if certain conditions are met. It does not matter what kind of medium is in use, synthetic fertilizer will cause salts buildup and intoxication of the plants, if proper flushing is not applied. During the crop, fertilizer gets absorbed by the plants in different quantities and concentrations, depending on many factors (temperature, pH, metabolism, mineral composition of the fertilizer). The plants intake feedings, and the leftovers sit in the medium and crystallize into small rocks of salts. This causes an increase of the medium pH and EC, and intoxication of the plants.

Flushing the medium is a tailored procedure, one that varies according to the type of medium.

In earth, salts build up at a slower pace than in hydroponics, but it is also more difficult to wash them away. Once the fertilization program is under way, it will take 3 to 4 weeks for salts to start building up, and another week before it can do any harm to the plants. Therefore, it is advisable to start flushing plants that are growing in earth around week 5-6 of the cycle.

When flushing, it is important to avoid over-watering; this means that the flushing should be integrated in the watering cycles. Before the flush the medium should be fairly dry, and after flushing it is very important to let the medium become dry and light before feeding or watering. The dry-wet-dry-wet cycle in the earth (sponge-effect) is what maintain the plant metabolism at optimal levels. For plants growing in soil, the flush is very important at the end of the crop, during the last 2 weeks before harvest. If properly flushed, plants will produce tastier buds, and the combustion factor of the dried material will improve. If plants are not flushed properly, combustion is slower and the flavor poor, and artificial.

When flushing the medium, it is very important to be organized to avoid water spills in the growroom. The purpose of flushing is to wash the medium, and as a consequence a lot of water flows through the containers down to the ground, and it is very important to drain away excess water from the growroom, so the climate stays good (too much water in the room will cause air humidity to climb fast, creating all sorts of issues). The easiest way of flushing is when working with elevated tables, and proper drainage pipes. Another way of effectively control flushing

In hydroponic mediums (from rock-wool to pebbles to coco fiber) the flushing process is easier to implement, because there is a higher degree of drainage. The texture of hydroponic medium favors flushing, and it is also more necessary than in earth.

When flushing hydroponic medium, it is very important to be exact with the values of the flushing solution. EC, temperature and quantity are very important factors. The EC of the flushing solution must be high enough for the salts to bind with the solution, but not as high as to form more salts. The ideal values are between 0.9 and 1.1.

The temperature must be in the 20-24 degrees Celsius range, to allow salt crystals to dissolve and unbind from the medium. If the temperature of the flushing solution is lower than 20 degrees the salt crystals will not dissolve, and if it is higher than 24 degrees the tiny root-hairs will be damaged.

And finally, the quantity of solution going through the medium should be at least double in volume (for example: 40 liters of flushing solution for a 20 liters container). In my personal experience, flushing with up to 3 times the volume is even more effective, as long as the drainage is quick.

Flushing is best done at the beginning of the light-cycle, so to favor evaporation of excess water and to let the medium begin the drying process faster after flushing.

Once plants are flushed, they tend to get lazy, and slow down growth for a day or two, but this is all part of the game. As soon as the medium dries again, the growth (or ripening) resumes fast, and even increases.

To double check the effectiveness of flushing, it is easy to measure the values inside the medium before and after flushing. First, pour some flushing solution through the medium. Measure the values inside the first liquid draining from the bottom, then apply the complete volume of flushing solution. At the end of drainage, measure again. At this point, the pH and EC readings of the flushing solution should be similar to what is draining out of the container.

In conclusion, flushing should be part of any synthetic feeding schedule, well integrated in the process. Water tanks capacity, and drainage, should be priority considerations when designing or building a good growroom. It can only improve the results of the grow operation.

Thought this might be useful

Peace Lams

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Lol Weedkipedia :) Thanks lamsbread ;)

Romeo :ph34r: , And finally, the quantity of solution going through the medium should be at least double in volume (for example: 40 liters of flushing solution for a 20 liters container). In my personal experience, flushing with up to 3 times the volume is even more effective, as long as the drainage is quick.

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Dust: "To double check the effectiveness of flushing, it is easy to measure the values inside the medium before and after flushing. First, pour some flushing solution through the medium. Measure the values inside the first liquid draining from the bottom, then apply the complete volume of flushing solution. At the end of drainage, measure again. At this point, the pH and EC readings of the flushing solution should be similar to what is draining out of the container."

Theres several stages of "flushes", so you choosed one to contradict me, Im sorry if I know much more then you, even if I dont need to grow in Hydro to answer a question.

And if you think you are sure enough to contradict me here once again, why you dont see the grow videos again? Franco and Arjan are "flushing" a 65L pots with just 60L of water, so, there goes your teory! Oh you even know more then Franco!! WOW

Learn to read and to think, and then contradict people, or in this case be silent! :ph34r:

You are always true to yourself, a j**k.

Take care

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Wen people use there brain, it does wonders :D

Thanks DKH for clarify the situation!

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Theres so much you miss in reading, Dust, but thankfuly just to prove you are a real J**k!!

"When flushing, it is important to avoid over-watering; this means that the flushing should be integrated in the watering cycles."

USE YOUR EC METER, instead of being closed minded and confuse the user that was asking for help! And of course that would be clearing you from make a fool out of yourself by showing you dont know what you are saying!!! :rolleyes:

And many more, but you would have to learn to correctly understand what you read, what simply doesnt happen with you, since you are so closed minded, and one more time just want to create a fuss with me!!

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Thanks for your helpful replies. It's my first grow and i wanted to be sure of everything before i proceed. I'll keep you guys posted once it starts.

Thanks again

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@ Romeu9 and Dust, Please guys you are mods, your not setting a good example.

@Panacea76

DKH's post if right on the money, and since you are using Clay pellets (which don't really absorb much if anything), 4 hr flush should be all you need.

as you are just trying to rid the clay and root zone of the salt residue, Check the solution coming out ever hour or so, you might not need 4 hours, but it depends on the root ball you are dealing with

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Flail, being a moderator doesnt mean I have to take shit with and something had to be done so the personal issues didnt mislead someone into a bad advice, just because Dust couldnt stand he knows not much about growing as he thinks and wants people to think. Thanks anyway.

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sorry guys didn't know a citation would take that much importance ^^

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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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