Proper PH question

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Dr MadBud
Mar 26, 2011
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I have a PH question for the experts here. I have run into a real thought provoking issue with maintaining proper PH. I have been growing in my stealth cabinets for less than a year but I have been partnered with my brother in the "grow-lab" for a few years now, doing hydroponics in both with much success.

It is my paradigm that sets up the PH to stay within as tight a range as possible around 5.8. I have found that during veg, the PH will drop on down to as low as 4.7 as the plants suck up nutrients and water. Then during the flowering stage the PH will rise to as much as 6.6 before I catch it and bring it back down. I have had plenty of success doing this. On my last 2 grows, maintaining this PH kept my girls green all the way to harvest. I have been only raising my nutes to just under 1000ppm. This same setup has been working for my partner accept that he runs upwards of 1200ppm and is using a different nute brand.

Here is where the paradigm shifts. My partner has found that if he keeps the PH at the middle 5s during veg like normal then, when they go into the flower cycle he lets the PH rise to around 6.0 for a week or two without lowering it back to the 5.8 level. He continues to let it climb without adjusting back down, almost allowing it to find its own level each week, while at the same time upping the nutes to the top level of 1250ppm and PH6.5-6.6. At this point he maintains this level all the way to the 7th week then drops the nutes to around 400ppm and the ph back to 5.9ish. His plants look and finish great.

He says that he can see the growth explode after upping the nutes and PH. His thinking is that the level of PH controls (like a throttle or regulator) how much the plants are able to eat. He says that when they are young, they can't handle as much nutes so the lower PH keeps them from burning from overeating. But as they get older they can consume more nutes and the higher PH allows them to do just that.

I have seen all of this in action and I am being honest when I say that his plants look and smell great (although I don't see the growth explosion that he sees). Is this a possible paradigm shift, or is he full of male bovine excrement? Can anyone tell me the key to how PH works with the uptake of nutrients and if there is a correllation to what my bro is saying? :huh:
Here is a good read HP, [URL="hxxp://[/URL]

I also know different strains like a bit different PH.
Hey are all the experts on vacation, or is everyone busy harvesting and trimming? I just read a book by a fellow named Jim McCaskill who was a noted hydroponics specialist (for multiple plants that don't include MJ). He said that the optimum PH for nutrient uptake for plants in general is between 6.0-6.5. This would correspond to the results that my Bro is having with his plants. What I can't ballance is the fact that I have great results with mine and can see vigorous growth with my PH held around 5.8.

Hey Growdude I did look at that info. It's definitely a good read and worthwile information. So if I understand it correctly the availability of nutrients is more about the soluability of different elements in a solution which occurs at certain levels of PH than it is about the plant. With proper PH present, a chelated chemical is able to be disolved in water enough to make it easily absorbed by plants, and if the PH is outside of this sweet spot the chemical molecules will clump together and will not be able to be absorbed by the roots. And apparently some plants have bigger openings in the roots that allow for the passage of these clumped molecules until they get too big. :)
Just with a quick glance, I would say that with the higher pH, the plants in flower are getting more of the nutes they need at that stage(P and Mg).

I would imagine that if one wanted to they could tweak each strain they have, to know exactly what pH and what Macro-nutrients and what Micro-nutrients are needed and at what pH is needed for each stage. But overall 5.8 is the best pH for all nutes to work together.

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