ive got a 400w MH about 8-10 inches from my plants, but Im moving quite a bit of air over them, I had it far away but they started to stretch... its all gonna be about your heat with cfl's your gonna want to be close... last grow I did but never finished I vegged with a 60w cfl about 2 to 3 inches from my plant the whole time but there again, I wanted alot of air movement, its just generally more healthy for the plants...