Fertilizer Needed?

[RayR]

Metal halides are way overkill for starting seedlings, too intense and too much heat will burn your seedlings. Not to mention they'll dry out those peat pots quickly. No fertilization doesn't help the situation, a plant can't photosynthesize without the raw materials it needs.
Always use T5's or T8's for seed starting and clones, and they'll save a lot on your electric bill too.

[PureHarvest]

Originally Posted by Swerveious

Yes I have transplanted some already before leaves even started to turn yellow. So I actually have some in 8 inch pots 18oz cups and alot still in peat pots. The room is about 12 by 12 and it's basically getting the same air as outside. It's my breezeway and I have 2 400 watt metal halides and a space heater so that's why I asked about humidity. I plugged a humidifier in a couple days ago and there's a little new growth and it's green not yellow. So im hoping that's all it was. First time using peat pots and I don't like em at all lol I have a couple hundred plants inside my house under t8's and they look as good as could be.

I keep a 430 watt HPS 4 feet above my plants. Perhaps you are way too close at your current height.

[Swerveious]

Well I started them under t8's but I had to many plants and not enough t8's. I got 5 metal halide ballasts and a case of bulbs for 90 bucks so I couldn't pass it up lol its odd to because it's really only the older tomato plants that are yellowing. Some peppers are a little but even the tomato seedlings that are only 4 inches tall have been under them since they got there fist true sets of leaves and they are really green. I took a couple more pics so people can see. I'm only a second year gardener so I don't have much knowledge really. So the older tomatoe plants that are yellowing are making me think it's just a fertilizer thing. I still haven't got a response about humidity tho. And the 400 watt being over kill the other seedlings look pretty good to me don't they?