Heat shouldn't be the problem, I'm only running 3 26W CFL's right now & have a mini fan in the room. Overwatering could be it though, I have been trying to just make sure the soil stays moist. I usually water some before bed & some when I wake up, but I do have drainage holes in the bottom of the cup too.
Well actually, letting the soil get get a little dry is good for the plant, because it makes the roots search for water hence increasing your root mass and making your plant grow. You wont need to water anywhere near everyday till those girls get close to flower...
I was kinda thinking that too, but I haven't been using anything but water right now. I have stopped watering it so much & I'll let everyone know how things turn out.