Well been busy fighting a leaf fungus infection, coming up on harvest, but looks like I might limp across the finish line, thank God, lol. So anyway on that study I have to admit its compelling and goes against the common wisdom that I and many other growers I know have considered to be gospel for decades. That said, I realize science is always pushing the boundaries and I'm willing to admit that what I know (or thought I did ;?) was wrong. And if I am, then I do sincerely apologize to anyone I've criticized or whose opinions I belittled. I know I can come off pretty heavy-handed and whether someone is right or wrong, I need to work harder at learning to disagree without being disagreeable.
Now that said, while I haven't had time to study this in depth and get a firm understanding of the implications of that research, I still KNOW what my experience tells me, and that is that green light does work in a grow room without causing problems like hermification ;?D That is something I and other growers I know have been doing for over 30 years.
Now one possibility is that, while plants may indeed absorb and use light in the green spectrum, how that spectrum is affecting the plants may not be involved in the process of photosynthesis or whatever else leads to vegetative growth. We do know that plants absorb much less green light because of the fact that they REFLECT quite a bit which, again, is why they appear green to the human eye. We also know that green light alone is not going to give a plant the energy it needs to survive, and while I haven't tried this, I'd be willing to bet that straight green light will probably kill a plant ;?) So I could see that while plants might indeed absorb some of the energy in this spectrum, that it may be quite limited and thus not stimulate all the same functions that the rest of the visible spectrum does.
If this were not true, then I and many other growers would be observing the results as plants switched from flower back to veg or would have had to deal constantly with hermification. I knew growers who consistently did work on their crops during the dark phase, sometimes for a couple of hours at a time and without seeing this happen. So logic tells me that something like this is potentially what is going on. So until I actually see any detrimental affects with my own eyes, I will continue to use green light to work on my girls whenever the need arises.