As most have stated you can have CFL within 2-3" of Tops of Plants, and indeed the HAND Test is the best way to check how much Heat Ya Ladies are feeling..Me(others may say different) I have my Giant 200w CFL higher than 2-3" for the 1st couple of days, maybe even for the first week..for 2 reasons..(A) to make em Stretch to the light a little and (B) because its not just Heat you have to worry about but Lumens> Too Much Too Soon..esp when just popping its head through the Dirt.
Peace