UV-B

Have heard a lot of research on the very positive influence that UV-B radiation (i.e. from tanning lights) has on the production of THC in plants..anyone tried it? What type of results or issues?

apparently it is required as a supplement to LEDs...what i heard in an LED thread

thnx Rk
I also heard it could suplement HIDs...know anyone who's used em?

quote from AN's vault on lights and info:
Cannabis sativa contains a number of secondary metabolites (cannabinoids) that are species specific. Some researchers contend that cannabinoid production is genetically controlled and influenced by environmental factors. Although the mechanism is unknown, a relationship exists between cannabinoid content and the altitude at which C. sativa is grown.

It was noticed, that wild, mature Indian C. sativa had the highest cannabinoid content at 1000 to 2000 metres elevation. One likely factor which may be of significance to cannabinoid production in both high-altitude and tropical environments is ultraviolet radiation. The Graduate School of the Department of Botany, University of Maryland undertook a study in 1986 on the effects of UV-B radiation on photosynthesis, growth, and cannabinoid production of two greenhouse-grown C. sativa chemotypes (drug and fibre). The plants were irradiated for 40 days, and then infrared gas analysis was used to measure the physiological response of mature leaves, whereas gas liquid chromatography was used to determine the concentration of cannabinoids in leaf and floral tissue. They found that the drug chemotype had a 23% increase of THC content, but not of the other cannabinoids. The fibre cultivar was unaffected.

There are 3 types of ultraviolet radiation, and only one is helpful in cannabis cultivation-and that is UV-B. UVA is found in the region between 320 and 400 nanometers on the spectrum and is the least powerful wavelength band of UV radiation. UVA acts primarily to cause the melanin pigments of the skin to oxidize (darken) creating the cosmetic tan and has limited power to cause erythema (sunburn).

UVB is found in the region between 280 and 320 nanometers. It comprises the wavelengths primarily associated with erythema, is also necessary for the production of Vitamin D in the skin and is primarily responsible for the stimulating increased melanin production. UVB wavelengths (at 305 nm) have 1,000 times more erythemal power than UVA wavelengths. UVB is the one friendly to cannabis. UVC is found in the region between approximately 100-280 nanometers and is called germicidal UV because of its proven effectiveness in killing single-cell organisms. Solar radiation in the UVC range is absorbed almost entirely by the atmosphere and that is fortunate considering that even a short overexposure to UVC is very harmful to the eyes and causes severe erythema, or sunburn. For this reason, protective eyewear should be worn, if you are spending a lot of time in a grow room equipped with HID lamps.

Now if you're interested in increasing your THC content by exposing your marijuana plants to helpful UVB radiation, you may want to get in touch with Wolff System ( www.wolffsystem.com ) or any local supplies carrying a line of Wolff System tanning lamps.

"While studying the beneficial effects of ultraviolet light on athletes, German scientist Friedrich Wolff noticed an interesting side effect - tanned skin. Realizing the appeal of a beautiful tan, Wolff founded the indoor tanning industry. His research led to development of indoor tanning equipment and lamp technology. Called "the father of indoor tanning," Wolff brought his European technology to the United States in 1978. He set the standard for the industry with specialized lamps and a reflector system that was ideally suited to indoor tanning. Today, the company operates in North America and Western Europe , and has patent licensees in Belgium , Canada , Germany , Sweden , Switzerland and the United States ."

If you're using tanning lights as supplemental, don't get rid of your HID lights. You still need them for the healthy growth of your plants, both in the blue and red ends of the spectrum. And one more thing, UVA producing black lights don't work on marijuana plants. They've been tried, with dismal results.

Hey I'll make it easy for ya, I've done it many ways doesn't add enuff to be worth the trouble imo. But doesn't hurt either. I added a couple tubes and moved them around and then concentrated in one area no big difference in potency or yeild. jmtc