UVB
Don't know if any of you have heard about UVB lighting . They use them in reptile houses to provide the reptiles with their UVB fix
. Anyway studies show that the (Δ9- tetrahydrocannabinol) in the trichomes on a cannabis plant abosrbs the harmful UVB rays to protect the plant . So the more UVB rays you fire at a plant the More THC it will produce to protect itself .
HPS lights don't produce any UVB at all
Green house glass is engineered to filter out UVB
Metal Halide lamps produce ALOT of UVB but it gets filtered out by the glass that the bulb is made off .
However , you can buy the specially made reptile lights from pet stores ( They're long fluro looking tubes ) . These produce alot of UVB and it doesn't get filtered out .
UVB is the reason why weed grown in Afghanistan can be very potent . Thanks to "Global Warming" wev'e now got holes in the ozone layer above afghanistan and Holland , these holes let more UVB rays penatrate so the plants in these areas go into THC production overdrive to stop themselves burning up .
Heres a link explaining it in a little more detail
http://www.youtube.com/watch?v=IPcpt3Be28o
Also two brothers both grew clones of the same plant , in exactly the same conditions apart from one brother had a Reptile UVB light in his growroom . Anyway at the end of the grows the UVB plant had 20% more THC on its main cola and other areas around the top of the plant .
The main problem with reptile lights is the penetration , they run at low wattages (25-48 watts) . And can only pentetrate a few inches (4-6) . However they are cheap about £20 for a 10% producing UVB light . If you had the money and wanted to splash out you could pick up a skin treatment UVB lamp for £400
these things run at 300-400 watts and really pump out UVB .
Basicly what im saying is if you drop your humidity and slam on the UVB rays when the plant is mid flower your going to get some beasty THC production .
*I copied this from somewhere else I did not write it but seems to explain it well*