True enough, but I can get way more trics using LED tech over HPS lighting. I used HPS lighting for years and years and once I changed over to LED the difference was ten fold.
It's going to take me a minute to find it, but I do have a video explaining how and why UV works. The trics actually do not like the UV exposure, so the plant as a defense build and extra layer to protect it's self, or at least that is the theory.
Not really, but I did give kind of a lame answer. Yes, there is actually a molecule that is actually produced from UV that can not be produced by HPS lighting, however it can be produced by LED lighting. Testing has been done and it is well documented as well. Another article I'll have to find, but I will.