Athosanswered grow question 6 years ago It's not so much a matter of temperature or humidity. Seedlings are quite delicate and it is i'll advised to put them under a MH lamp so young because they put out too much heat, You would do much better having them under a LED bulbs / T5, but if you don't have that, you just have to increase plant to lamp distance. Start at 3 feet away from the light, then as they get used to it, you can decrease it slowly to 2 ft.