Thank you kind sir! I remember karode saying between 6"-12" for these lights with cacti seedlings. I've heard a lot of horror stories talking about seeds burning up, like the one above hehe so I wanted to make sure I'm not in danger of that. 13" feels like a nice safe distance for now and I do think I already see some of the seeds beginning to open. I'm curious if anyone out there uses a similar light and starts seeds as low as 6" below? I was looking everywhere for good trays with humidity domes, they are really hard to find without having to pay triple what they are worth in shipping charges... So I went to walmart looking for Rubbermaid or something and ran into these for two for 3$ they have some large ones too that are the same price per. This particular size fits 12 of the small Styrofoam cups perfectly if you cut the top inch or so off of the cup. 20 seeds per cup so I'm able to sow 240 seeds in a 12"x9" area. These lights came out to 109$ for two of them 20k lumens all together and now I have an awesome workspace :sunny: I figured I would be spending near that in CFL's to achieve a similar lumen output and this way the lights are nice and organized. I'm going to be having a lot of fun with them I can already tell.