Is UV light necessary to change CBD to THC?

Can you grow potent pot in a glass/UV protected green house ???

CBD doesn’t turn into THC.

You can grow weed w/o uv light, no problem. Many growlights don’t have that spectrum, either.


Very high levels (harmful) can influence THC production but in general it has no bearing on us growers. Directed spectrum lights don’t have much if any UV.


Ultraviolet light participates in the biosynthesis of THC acids from CBD acids, the conversion of CBC acids to CCY acids, and the conversion of CBD acids to CBS acids. The genetically determined inability of certain strains to convert CBD acid to THC acid makes them a member of a fiber chemotype, but if a strain has the genetically determined ability to convert CBD acid to THC acid then it is considered a drug strain.

So…i guess my Question is: Am i better off growing W/O The damn glass greenhouse !?

Please read below…410…

Could you please cite where you got that info regarding CBDA converting to THCA. Also, could you please relate how you understand the process you described would work on a growing plant?

I know it can be manipulated, but it’s not what happens on our plants to make THCA. At least not in my understanding. I’m trying to figure out what your goal is with using that info.

As for the greenhouse, that depends on your climate and other grow requirements. Completely up to you if you want to use it.


i got that info from “marijuana Botany” by Robert Clarke ! He states that it’s the UV spectrum that causes it. And my concern with the glass is simply that it does not allow the UV spectrum to pass through like plastic does .

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“In plants, THC and CBD are derived from their acidic precursors Δ9
tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) (refer to
Figure 2). THCA and CBDA are both derived from cannabigerolic acid
(CBGA). The final step differs, with THCA synthase and CBDA synthase
producing THCA or CBDA, respectively, from CBGA. Subsequent
decarboxylation of THCA and CBDA via light exposure, heating, or aging,
results in THC or CBD.[10-12]”

Taken from a pdf of a WHO study:


Thanks betty for trying to help me understand…i still suspect that growing with full spectrum UV increases the potency perhaps rather than w/o it…don’t you ???


Maybe @dbrn32 can shed a little light on the subject. (Did you see what I did there?)




Found this, might help. Good citations at the end.

Problem with uv light studies is that there are well run studies showing that it does create higher thc levels and studies showing that there isn’t any increase in thc levels. For the record, the most respected studies supporting uv increasing thc showed thc increases of 3-5%. For example 24% thc with no uv and 25% with uv, an increase of 4%. Not from 24% thc to 27-29% thc like some people seem to believe. That was also specifically uvb.

Glass in general is known to scatter shorter wavelengths. Doesn’t really matter if its special uv resistant glass really, but I’m sure some glass does more than others. In short, I wouldn’t worry about the glass keeping you from growing good weed.


Yes you can grow potent weed in a UV protected greenhouse. Indoor growers do it all the time.

A little UV can be good because the cannabis just thinks the sun is angry this week and will try to produce trichomes to protect itself (the trichomes, the more cloudy, the more amber, the more yada yada). So you’ll see lights with UV diodes. But you don’t need them.
Too much UV and you’ll kill the trichomes, the plant, and give you skin cancer.
As far as CBD turning into THC through UV…both would sooner break down all together under enough UV before a transition occurs.
(But didn’t say CBD can’t become THC because it can through chemical methods that are over my head)


It can be manipulated chemically, but inside a plant…THCA is not derived from CBDA.


I’m with @EclecticJack. But I can make bomb volcano with baking soda and vinegar.


I’ll stick with peer reviewed science and such. :grinning:

The greenhouse is a personal choice. What are you choosing @david2?


Yup, I meant over my head part. Way too busy making things explode when given the opportunity.


Mentos and Diet Coke should work @dbrn32 lol. Can’t believe I’ve never actually done that.