I have used a 400 MH on seedlings; no problem, yeah, 2 foot at least. But, now I go the first 3 weeks with T-12 fluoro tubes in 5000k or 6500K cool white...:thumbsup:. No chance of burning them and no excess heat is generated. Then I switch to the 400.

IF, using t-12's; you do keep the bulbs with 2-3 inches of the seedlings.

either way, good luck growing...:thumbsup: