Hey, oldmac, congrats on your great grandsond :thumbsup:. Some good pot and a great grandsome is the recipe for the best Sunday morning! (well, probably still great without the pot :stoned

Weez, its difficult to say the total emission from a data of irradiance. 50microwatts/cm2 would equal to 500mW (0.5W)/m2, that is a good irradiance for UVB. But without knowing how far is the lamp on the measurement, or the coverare at such irradiance, its difficult ot say if its high or low. Areas exposed to 0.5W/m2 of UVB are receiving a very good dose (level of tropical high areas if I dont remember bad), but we dont know how big is that spot. Likely the average UV-B irradiance on the grow area was lower. But in theory, with 0.2W/m2 effect should be noticiable.

Im kinda surprised for your results, oldmac. Not about quality effects, but about gross production. Although Ive seen conflictive results with UVB experiments, a clear improvement of dry weight with UVB treatment (from veg!) is something I havent seen before.

Although I havent planned to experiment with UVB, you give food for thought with your results. Unfortunately my spectrorradiometer dont cover UVB range, its VIS-NIR. I feel UVB result are strongly dependent of actual wavelenght (I believe radiation starting about 285-290nm is required) and dosage (I believe same spectrum may vary in effect at different dosages).

Anyway, very interesting. I note that from now on, if I want ot use UVB suplementation, ill do it on veg too.

PD: I agree results are due UVB. On some biological effect, UVB works on same direction than blue, but on others works on the opposite direction.

I forgot to make a question, what was the humidity level?