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ghsc 3 flush technique


hazeydayz
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just a quick question really i understand the 3 flush's before week 6 with soil but i have ventured into hydro and was a bit confused !

my delemare is im using NFT method and was wondering how long to leave just pH balanced water in the tank to archive the best results for the 3 flush's to work or would it be better to forget the 3 flush and do a really good 2 week flush at end

any help much appreciated

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thanks jimmy and DKH thats grate i think i get that so if i was to follow the ghsc 3 flush method i would step the ec down over a few days then flush with week solution then bring the ec back up to full strength over a few days

then at end of flowering step ec down again until you reach a pure water solution then flush for a week . is this anywhere near right please let me know

got another question for you what signs of changes am i looking when you say minimal sighs i.e. droopy leafs ect

thanks for your time and effort to reply

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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.
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Franco very informative and excellently written; you are a true grow guru.

thanks for taking the time, as this is a subject of interest to us all, soil or hydro growers.

it is shame that more growers from Amsterdam do not flush well, as the smoke there would be the best in the world, only if, the growers would flush better.

I understand why they do not, as it is a very competitive market and no doubt it is hard to make money when the prices are as low as 9 euros a gram. Still as a customer i would prefer to pay more and have a product that burns well and taste better. I do understand that proper flushing does affect yeild, but it does improve the favor and tastre, and these are important to a smoker as well.

thanks hazey for asking about flushing.

john

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hello mate i understand the technique but i use a flood and drain system it fluds every 3 hours and is just clay pebbles which gets good aeration to the rootball anyway.. so would i need to flush out 3 times? and also on another topic would i haave to step the nutrients up if its not constantly available because it only floods every 3 hours? help would be appreciated thanks

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I did this flushing technique for the first time on my last grow and my plants loved it :) I grow in soil and I did pretty much exactly what Franco said above, I didn't really know what I was doing but luckily I sorta guessed it right ;) my water may have been a bit cold reading the above post but it makes sense and I will work on that next time.

One thing I did notic however is that the 2nd time I flushed the soil started to feel a lot firmer, due to so much water going through it.

Franco does this have any down sides for flushing in soil ? Or do the obvious benefits out way this ?

Cheers for the post, but I got this from yr grow guide on the greenhouse website :)

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Hi davieboy, I personaly always mices the top of the soil before watering and every few days, that way it aearate the soil, dry better, might bring more oxygen to the roots a little too ^^ But also break "bricks" of soil so when you water, the water penetrates uniformly in the soil ;)

So a few days after the flush take a fork and break the soil ;)

Careful not too break too many roots, or let them appearing to the light

have a good grow man ;)

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