I've just been reading on wikipedia that scientists think THC might have been used by plants to block out UVB rays, much like we slap on suncream when its sunny to avoid sunburn. So that made me think, maybe you could stimulate THC production by exposing the plant to UVB rays, for example from a fly zapper lamp? Then maybe the plant would produce more THC as a sort of homeostasis thing: it detects more damaging UV rays, so it grows more THC to block them out.
What do y'all think?

I do it. A lot of people do it here. I use a 10.0 reptile bulb that I put into a little 24 watt 12 inch or so ballast fixture I already have. The fluro bubls are the cheapest but they make cfl versions. The 10.0 version is the buklb you want. However as you get deeper into the science of uv there are compaines that make hid bulbs with various versions of uv for every stage of the plants life that also use 5.0 in veg or something that I cannot fully recall. There are a ton of huge threads on here. I am not unhappy with the results and I am not usng as much as I should for my 4x4x6 tent but there must be some better than nothing as the study is legitamate. Search this before the whole site yells at you! lol. jk

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i do it too...search "uvb thc and me" in youtube.

i used them for my last grow and not only did my plants get happy it rewarded me with a great smoke and super sticky buds so yea ur not losing nothing by doing it

Ah right, thanks for the advice
How long do you run it for? The video that aeviaanah pointed me towards recommended 5 hours a day.

Just watched it, very interesting. Cheers!

Ok I'm sold

+rep to all 3 of you

do like 2 hours the first week then move it up to 5 hours and that should make a difference u will see the plants react positively to it

Thanks for the advice. I think I'll go for one of those 10.0 CFL ones (ie the ones which fit in a normal light socket and look like energy saving bulbs)

dats exactly what i use

I'm almost certain it's a myth. In fact, I'm finding that the lower loose buds on the plant (the ones shaded from the light) are just as potent as the tops. Also, I've noted significantly more milky trichome color after leaving plants in the dark for several days pre-harvest.

One of the key premises of that argument is that high THC weed comes from areas of high UVB. If evolution is to credit this accomplishment it is the genetics of the plant and not environment (additional UVB) that is responsible for higher THC. It is just as likely (perhaps more likely) that THC is expendable and high UVB light destroys the extra THC faster than it is produced - hence the boost in THC produced by a long dark period pre-harvest.

The only actual evidence I have of this is that trichomes are about 300% more milky after a long pre-harvest dark period. I'm assuming from general practice that THC is responsible for the milky color. But the bottom line is that there is no conclusive proof either way. Some insist that the reptile bulbs are key - I'm not one of them.

hey maybe ur right
but since when does extra light on a plant actually hurt it?