Is UV light bad for marijuana?



I’ve heard arguments for and against the UV light being used on marijuana. Does it have any effect on the plant’s stoniness?

Thanx, the joker


Hi Joker,

Ultraviolet (UV) light is situated in the bands between 300 and 400 nanometers. Humans can’t see it, but it’s the type of light that is responsible for affecting our pigments and causing us to tan. It can also affect plants in a number of different ways. Apples will not produce their distinctive red color without UV rays, and some plants use this spectrum to regulate certain functions.

UV-B light has been proven to change the quality of the bud. I’ve heard stories of marijuana buds grown at higher altitudes being considered higher quality than the buds produced on flat land. Plants at higher altitudes receive more of the UV-B light because it is filtered out by the atmosphere at those heights. One controlled experiment showed that the concentration of THC increases linearly when UV-B light increases. With reptile lights (10% UV-B) or tanning lights (even higher percentages), you can increase the stoniness of your marijuana garden. There is also an argument in favor of flower forcing early when the plants are outdoors. The amount of UV-B light that reaches the earth is considerably higher in the summer than in the fall (with June 22 being the most potent). Plants that are forced early outdoors will get more of these powerful rays to their buds, producing more cannabinoids.