Arlene, I have eight LED fixtures, but because of my greenhouse size, I have stacks of shelves and thus needed water-proof LED fixtures. I don't know whether they are very effective to tell the truth. I have had them for almost a year and can't really tell your that that make much difference. I wanted to supplement my lighting on the second and third row of shelves, and that's where I use them. There is no way I can give a comparison of using these LED's and not using them. I simply have too many variables. I wish I could be more help.
