[compost]

Originally Posted by hippydan

It's already been said multiple times in the thread. The whole point of harvesting a plant during the dark cycle is to get it when the majority of starches are in the plant's roots, and not in the buds themselves. If you're going to flower a plant for 55+ days, what is one more light cycle going to do for potency in the grand scheme of things? Sure it might be slightly more potent, but it's going to be harsher smoke.

From what I am reading below from spurr seems to suggest otherwise.

Originally Posted by spurr

Not to my understanding, where do you find that info? AFIK, only < ~25% of the photosynthetic assimilate (e.g. carbohydrates/starches) produced by the plant is moved into the roots regardless of day or night. Light independent reactions of C3 plants entail various functions, such as conversion of photosynthetic reactions into starch (that happens in light and dark).

[hippydan]

At the end of the day there is rarely an "end all be all" solution. Do what works best for you, and you won't know what works best if you don't try everything. Either way, light or dark harvest, if it made a huge difference one way or another, someone would have already figured out which way worked best. Even if they couldn't explain why, they'd still know. So far all I'm reading is scientific papers that are older than I am and second hand opinions developed by people that don't have any rock solid evidence to support one way or the other. People are only doing what works best for them, and in the end, why do anything else?

[Cannabologist]

Spurr:

That said, the effects of other spectrum of light in PAR range do not have a great effect upon THC > CBN conversion AFAIK.

- That’s very good to know. The clever observer can see how high I am in certain posts, I say both, and I put in 3 variables, which too, I’m going off ancient memory, not actual fresh sources.

However, in terms of light, UV-b has a strong effect upon increasing THC production in cannabis (see what I have posted in the UV-b thread).
Along with light, nutrients (i.e. nitrogen) and temperature have rather notable impacts upon THC accumulation.

- I have read of some of UVbs effects, but not yet everything, such as papers you have uploaded on the issue, which having acquired I want to pine over. I’ve been strongly interested in the possible effects of UVb radiation and Cannabis with the speculation bantered about. I’m wondering how many percentage points we are talking.. All it all though, it just makes me wonder why would the plant produce more trichomes, and more THC/Cannabinoids/terpenoids, if it did, in the presence of UVb. What is the mechanism, why and how did this adaptation arise, if it is an adaptation. I feel as though the achene itself, among the polymorphs, many seeds bear stripes/banding and dark coloration from greys to browns, and these are adaptations by the seed coat to protect the embryo from ultraviolet radiation which could cause deleterious mutations.. So...

Cannabinoid amounts (quantitative) is a phenotypic trait that is strongly affected by the growing environment, fertilizers, etc.

- Well, I’ve seen some studies that show limiting effects with the application of nitrogen from the Journal of Industrial Hemp, I’m wondering how greatly cannabinoid amounts are affected. From off the top of my head, studies involving light could influence ratios by a couple percentage points. I forget how much nutrients can affect ratios, perhaps a few points as well (certainly nutrients appears to be quite an area of expertise for you).

- I’m going to review some studies for potential efficacy in altering cannabinoid amounts to see how much can each influence.. light color, nutrients, UVb, etc.

Cannabinoid amounts (quantitative) is a phenotypic trait that is strongly affected by the growing environment, fertilizers, etc. And cannabinoid ratios to other cannabinoids (i.e. chemotype; normally qualitative) is a genotypic that is not strongly affected by the growing environment, fertilizers, etc.

- You explained it so much more concisely

[TheDillest]

Ive also read from multiple sources that UVb light is a key component in turning the precurser CBD into THC, which then degrades later to CBN.
I don't know if that information is actually true, but if so it would put anyone trying to maximize the THC content of their buds in an awkward position.
If UVb light is what transforms CBD into THC, but is also the primarily responsible for the degredation of THC to CBN, than what does the grower do?
If he applies UV he will create more THC.
But at the same time that he is creating THC he is also degrading THC into CBN

Assuming all of this data has any truth whatsoever(more research is needed on my part before I can claim this information to be valid), than what I imagine would be very effective is to withhold any amount of UVb light for almost the entire flowering period(using HPS lamps) allowing CBD to accumulate in the trichromes.
Then nearing the end of harvest introduce UVb lighting for a brief period of time to convert the CBD into THC, but not so long as to convert large amounts of THC into CBN.

I have my doubts on this theory of the importance of UVb light in transforming CBD into THC, because if it were true crops grown under HPS lamps(especially if placed in vented hoods due to the extra UV filtration of the glass) would have extremely low THC concentrations, which is not something that has been observed

[de145]

Dillest: CBD does not transform into THC. I think you are mistaking the precursor compound of THC which is THCA the acid form of thc naturally occurring in the plant.

[grandmaster B]

the worst of all information is MISINFORMATION!

[Reaper]

Sorry to dig up an old thread, but am currently looking for an answer to my situation:

I have an opportunity to sell some buds into a new market. However, I will need to LOWER the THC % of the dried flowers to meet the legal limits.
Does anyone know of a process or procedure than one can undertake to degrade the THC fairly quickly?