not sure really, thats not a cfl, its a 65 watt bulb, i'd try about 10 inches to start, maybe 8, but keep an eye on it, if it seems to be having a bad effect, move it out to 12 inches...its kind of hard to tell how far away it is now, the stem just looks like its been reaching, trying to grow up to the light, which usually means it needs to be a little closer.