On the subject of the Bugbee UV trial, here are some direct quotes from the paper.
This is, IMO, a poor excuse for using high-CBD instead of high-THC plants and then trying to justify the results in the context of medicinal cannabis (which wasn't tested).
It also shows up Bugbee's lack of experience wth cannabis. I'm growing a haze right now that is close to the landrace strains of the 70s and it has tested up to 20% THC. It is derived from Neville's Haze that was bred in the late 80s, early 90s.
I mean, I was there, smoking landrace pot in the early 80s imported directly from SE Asia, and there is no way that shit was 3% THC! Let alone the sativas we used to grow outdoors in Australia during the same time period.
Indeed, just 5 minutes (300 seconds) of UVC degraded cannabinoids by 15% according to Bugbee, so at least the elephant in the room was addressed.
5 minutes of 255nm = 15% reduction in cannabinoids. UVB is less powerful, but just imagine hours and hours of it!
The point is there are a lot of holes to pick in this study for those who know what they're looking at.
^ To say that cannabis 40 years ago only had 3% cannabinoids (that includes TOTAL cannabinoids, CBD and THC), is both ignorant and crazy. Testing methods in those days were not the same – they tested seeds, stalk and leaf in addition to flowers – and plants were not subject to the same quality controls as today's high-THC varietals.Regardless of the chemical profile, UV photons have not been shown to increase cannabinoids in high cannabinoid cultivars. The varieties 40 years ago contained around 3% cannabinoids, less than 20% of modern medical cannabis cultivars.
This is, IMO, a poor excuse for using high-CBD instead of high-THC plants and then trying to justify the results in the context of medicinal cannabis (which wasn't tested).
It also shows up Bugbee's lack of experience wth cannabis. I'm growing a haze right now that is close to the landrace strains of the 70s and it has tested up to 20% THC. It is derived from Neville's Haze that was bred in the late 80s, early 90s.
I mean, I was there, smoking landrace pot in the early 80s imported directly from SE Asia, and there is no way that shit was 3% THC! Let alone the sativas we used to grow outdoors in Australia during the same time period.
^ Smoking gun. Yes, UVB does degrade cannabinoids – we have tested and seen it.Cannabinoids absorb UV photons, which may lead to degradation. It is possible that UV treated plants synthesized cannabinoids that were degraded by the high-energy UV photons, but it is difficult to draw conclusions from this study. In a separate study in our laboratory, we applied a UV-C (peak ~ 255 nm) dose of 0.01 mol m-2 (UV-PFD = 30 μmol m-2 s-1 for 300 sec) to dry flower that had been ground and spread in a thin layer. Cannabinoids declined by about 15% (unpublished data).
Indeed, just 5 minutes (300 seconds) of UVC degraded cannabinoids by 15% according to Bugbee, so at least the elephant in the room was addressed.
5 minutes of 255nm = 15% reduction in cannabinoids. UVB is less powerful, but just imagine hours and hours of it!
Bugbee says 405nm doesn't work, but fails to include the methodology, if used in combination with UVB, then I can understand why. The amount of UVA exposure will also influence net cannabinoids. Our own tests using just 405nm show otherwise.There is potential that light sources with different wavelengths or ratios of UV-B and UV-A would lead to an increase in cannabinoids. Llewellyn et al. (2022) used a similar fluorescent UV-B/UV-A light that was used in this study. Rodriguez-Morrison et al. (2021) used narrow-band UV-B LEDs (peak 287 nm). Llewellyn et al. (2022) also demonstrated narrow-band UV-A LEDs (peak 385 nm) did not affect cannabinoid content. Studies from our own laboratory with 405 nm LEDs have confirmed this finding (unpublished data). Based on previous studies, neither UV-B nor UV-A significantly increase cannabinoids in high-cannabinoid cultivars.
Just 4 umol/m2/s of UVA. They also used a ratio of 1.5 UVB to 1.0 UVA PFD, although the amount of energy in the UVB was even higher than this ratio.4.3 Relating UV treatments to sunlight in the field
A common criticism of research on UV in controlled environments is that the conditions do not adequately reflect the field (Caldwell et al., 1994). The maximum PPFD from sunlight on a clear day in the middle of summer is about 2000 μmol m-2 s-1. The UV-B PFD is about 7 μmol m-2 s-1 and the UV-A PFD is about 160 μmol m-2 s-1 (Caldwell et al., 1994). In this study, UV-B PFD was about 6 μmol m-2 s-1, but the UV-A PFD was only about 4 μmol m-2 s-1. Previous studies used UV-B PFDs ranging from 0.01 to 1.6 μmol m-2 s-1 and little (Llewellyn et al., 2022) to no UV-A (Rodriguez-Morrison et al., 2021).
The point is there are a lot of holes to pick in this study for those who know what they're looking at.