bluebear, i dont think i explained well, the clones are well rooted and right now I've had the HPS on them for about 13 hours now and i don't see any problems. I do have excelent ventilation. ! 6" vortex cooling and air cooled !K HPS and a 4" vortex for exhaust. I can get the lamp really close, about 10 inches before I notice the temps getting out of hand.