Hey Drfrank just wanted to give you my idea on uvb lighting and how come there bad our atmosphere blocks out almost all UV lighting if it didn't nothing would grow and life as you know it would not exist on Earth . uvb lighting not only causes cell break down in plants , it also causes Genetic issues it causes Cancer, and other diseases to humans
Plants grown under artificial don't get a lot of uv light, most "grow lights" are only really interested in photosynthetic spectrum. Your plants may get sun burned because they aren't used to uv light. When growers move plants from under lights indoors, I always remind them to "harden off" their plants. Basically, they put them in a semi shaded spot, and work them up to full sun if that's what they need. If you just stuck the plants in the viv, at ground level they might get some minor burn, but the plants closer to the bulbs, might get severely burned, and actually die. If you can start them off farther away from the bulb, and then slowly move them closer if you're really worried about killing something from uv burn(plant wise). UV burn will turn leaves a straw kind of color. I am assuming that we're talking a new uv bulb here too, and not one that has lots of hours on it, since that will probably change the uv output just like it changed the lumen output.
Sorry for longish post, hope that better explains it for you.Physiological and developmental processes of plants are affected by UVB radiation, even by the amount of UVB in present-day sunlight. Despite mechanisms to reduce or repair these effects and a limited ability to adapt to increased levels of UVB, plant growth can be directly affected by UVB radiation.Indirect changes caused by UVB (such as changes in plant form, how nutrients are distributed within the plant, timing of developmental phases and secondary metabolism) may be equally, or sometimes more, important than damaging effects of UVB. These changes can have important implications for plant competitive balance, herbivory, plant diseases, and biogeochemical cycles.