I saw video yesterday where the dude was stressing UV importance. It seems like so many have an angle.
UV Radiation and PSM
Different wavelength ranges in UV radiation result in varying cannabinoid accumulation (Lydon et al.,
1987; Magagnini et al.,
2018). It has been nearly four decades since the first study suggesting that UV-B (280–315 nm) radiation affects cannabinoid accumulation in cannabis plants (Lydon et al.,
1987). UV-B radiation did not impact cannabinoid content in both drug- and fiber-type cannabis plants, with the exception of Δ9-THC in bud tissues of drug-type cannabis plants. When the daily dosage of UV-B radiation increased from 0 to 13.4 kJ m−2, the Δ9-THC content increased from 25 to 32% (Lydon et al.,
1987), suggesting that Δ9-THC was a UV-B photo-protectant (Pate,
1994). It was further noted that UV-B radiation increases trichome numbers. Altitude may be equally important. Increased solar UV radiation results in higher CBDA, terpene, and cannaflavin content in the hemp variety “Kompolti” (Giupponi et al.,
2020). Notably, UV radiation sources used in both studies had relatively broad spectra, compared to electrical UV radiation sources, such UV-discharge lamps and light-emitting diodes (LEDs). It is unknown if there is was an interactive effect between UV-A (315–380 nm) and UV-B radiation, as a high percentage of UV-A radiation was present in both the UV-B and control light treatments (Mirecki and Teramura,
1984; Lydon et al.,
1987; Giupponi et al.,
2020). A subsequent study examined the impact of UV-A radiation on cannabinoid accumulation, and reported increased cannabinoid levels other than Δ9-THC (Magagnini et al.,
2018). Low percentages of UV-A radiation (2%) from full-spectrum LED arrays induced an increase of several cannabinoids, including CBD, CBG, Δ9-THC, and tetrahydrocannabivarin (THCV), compared to a high pressure sodium (HPS) lamp that contained 1% of UV-A radiation (Magagnini et al.,
2018). Clearly, more studies are required to clarify the impact of UV radiation on cannabis PSM accumulation.
And here is the newest study that was recently posted in the forum
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9551646/