One can use them but they need a huge distance of at least 24-30" and even then you can only use them for 1-2h per day splitted in 4x 10-30min. Plants need UVA too when you treat them with UVB and they need much more UVA than B to not getting cell damage. They have adapted to natural UV levels which can be between 1:4 to 1:20 depending where you care.
1: 4 is outback level or in 2000m height, 20:1 you maybe get in the scottish highlands.
PureUV bulbs have an exact opposite ratio and have 3 times more UVB like A(75:25%) so far from being natural.
I myself know this unfortunately since a few weeks as I have talked with a professional gardener who regularily use UVB/A for different sorts of kitchen herbs like rosemary. They also use T5's and some kind of quarz burner but I've not seen them. He only told me that they are more complicated and need additional UVC filters cause they create UV from A-C.
When you put a rosemary under a reptile bulb it takes around two weeks and you can see the difference with the naked eyes. The leaves get much darker, new leaves also stay a little smaller and the surface gets really shiny because of the higher amounts of oils. They also start to feel sticky and the smell is unbelievable. Rosemary, thyme, basil, and so forth produce all the essential oils and they all profit from UV treatments.
He says, he also tested it with different tomatoes and the lab tests have shown that even the nutrient content has increased. Exspecially vitamins and so. They have found different vitamin/mineral profiles compared to no UV light.
He says, this is one of the reasons why the nutrient content in vegetables has partially gone back by 50% and more. Too many greenhouses and in all of them the UV light is eliminated by glass or plastic material. They develop already UV-permeable hollow panels that let UVA and B light pass through.
Sometimes they only use UVA to bring out more colors and for other species the use both, UVA and B.
His kitchen herbs are only for the locale gastronomy, you can not buy them anywhere else.
He recommended me higher output T5 reptile bulbs because they mimic the sunlight and last at least 1500h(still 80% or the initial output). The spectrum goes "only" down to 295nm which cause less stress but they need more time compared to stronger bulbs to cause the same effect.
If you want more UVB for short treatments get the Solacure bulbs. They are 3 times stronger like 12-14% reptile bulbs but the still have a natural ratio with 5 times more UVA like B. Their spectrum goes down to 280nm which means a smaller dose is neccessary to get the same effect. Nevertheless its the old T12 standard its currently the most efficient UVB bulb "suitable" for growing.
That's the Solacure spectrum.. You see, only a little is exactly 285nm and the amount 280-320nm is at least 4 times less as the area from 320-400nm. Optimal would be 285 and 365nm and a ratio around 1:5..
View attachment 4327046
And thats the Arcadia 12% spectrum compared to natural levels. Remember, the natrual level is measured somewhere in GB.. The higher you go or the closer you come to the equator the more shifts the green line to the left. At the highest levels the natural curve starts just below 280nm because UVC is still filtered by the atmosphere even in 5000m above zero.
@Randomblame
I wonder if I might ask some advice on these bulbs as I missed something.
I later realized I purchased these bulbs below.
https://www.solacure.com/superb.html
vers
the flower power below in link
https://www.solacure.com/flowerpower.html
Will I get the same responses and what is different as I think at the time I liked the even plateau and long exposure times I did not realize that I selected a different bulb than the flowerpower.
It does say generation 5 vers 4 for the flower power not sure what to think?
It is the 285nm being lower that may affect things I thought as I can get another couple bulbs in flower power as my lights are double 32 watt be running em at 25 watts 4 bulbs so 100 watts.
I have noticed I can leave the other bulb on for 6 hours no problem now and leaves on top are not affected just oldest leaves from beginning still bear some scars but still alive with slight tan.
Perhaps adding flower power too during later flower will be good?