So you find that you actually get some useful warmth from the T5? How close to you have the tubes to the plants? I had thought I would set it at about 8 inches at first and then lower it as they got used to it but maybe you don't need to do that at all. At this point there's not even any reason to turn on 4 of the bulbs for a tiny plantlet but once the plants spread out then I should be able to use all the bulbs. (Well, assuming that some unpredictable disaster doesn't strike!) Thanks for the feedback; I was hoping to hear from someone who uses T5s.