I thought increased frost which I had long ago from Mastercolor cmh retrofits may have been from UV but I got the same effect under blurple but very tiny buds. I know that cmh emitted UV from several welder flash incidents. I also know the LEDs had none.
Now in a year of flowering with cobs, same strains have more frost than ever, and no UV. I have a suspicion that the plants react to increased deep blues because in millions of years of adaptations, when these deep blues are intense, the slightly shorter UV wavelengths are also present at harmful levels. If so, increased blues would signal the plant to take defensive action.
Just thinkin' at 6:21 AM.