Why do most hydroponic nutrient companies recommend reducing overall nutrient concentration and drastically reducing nitrogen concentration in the last third of bloom? Does it increase THC? Is there any data?
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Nutrient uptake by the plant peaks in late veg and then begins to decline through flower.
Here is a chart of hemp nutrient utilization. This is for fiber and seed production. You could mentally extend the graph a bit for extrapolated what flower would be. This is field production, but I am providing it more as a visual for how nutrient uptake rises and falls over time.
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It needs be also known that Nitrogen(in its various forms) that gets uptaken, but no used (over applied), will eventually be turned and stored within cells as Nitrite.
Once in that form, the plant will not be able to access the nitrogen within the nitrite , therefore you can very well see a lot of nitrogen defficiency in plant full of nitrites.
Nitrites, are highly suspected to be carcinogen, especially when they are burn/vaporized and inhaled
no matter how much the grower flushes or how yellow the plant becomes before harvest, what is stored within plant cells will not magically come out. Therefore why supply something that will not be used?
Cheers
Cheers
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Thanks guys, in the early '80s I got this book at a head shop on growing MJ. In the book, he referenced a nun in France well known for growing pot. She claimed that withholding nitrogen towards the end of bloom would increase THC.
I swear, this is a true story
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While there are good reasons from a plant development perspective to modify the feed formula, even weekly, during the ripening process - the main reason in a hydrponic grow for lowering the nutrient levels (leaving the Nitrogen, Nitrite and plant development issues out of the mix), is so as to not shock the plant when transitioning to flushing with water only.
I spoke with a soil grower who immediately cuts Nitrogen in the second half of bloom - but the soil buffers the effects. His blueberry packed a serious punch at Weedcon West today in Bel-Air.
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Another input here. For a long time, we used the Current Culture ppm and NPK specs for their supercharged aeration as that seemed to be the closest to aeroponics. NPK starts out at about 3-1-3 and at the end of bloom it was more like 1-3-4 if I remember correctly. ppm is also way down. Supposedly their formula was developed at UC Davis. Anyone in the forum know about this?
Thanks again in advance. There are some really good growers on this forum and really appreciate their inputs.
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