I didn't have a T5 so I put my week old seedlings under a 250 MH fairly high up. Needless to say I stunted their growth and almost killed them. If you do put them under the big light get it far away from them. But if you can invest in a set of T5's. They are wonderful for germination and seedling stage.Is it ok to put new seedlings under a 600 watt MH a day after they came threw the dirt?