6 inches is way to much for CFls I kept mine at any where from 2 to 3
inches from my plants. A half a foot is to much, Cfls are usually kept as
close to the plants as posable without burning them. Put your hand
under the lights to see if its hot at 6 inches if not move your lights
closer to the plants but keep an eye on them they can and will grow
into the lights and burn I had that happen a couple of times so adjusting
your lights is about an every other day thing with Cfls.