another picture

Can anyone help??

Do the cups have drain holes? How often are you watering? Are the cups sitting in water?
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Cute cups! How many ounces are they? (No, mto, you do not need to buy cute cups! You already have cups.)

It is possible your seed starting mix doesn't have any fertilizer in it.

If you fertilize use a very dilute mixture because you can burn the roots.

Too much water, poor drainage can cause them to yellow. If they don't have any fertilizer in the mix that could also cause them to look pale. Sometimes it is easy to go overboard trying to fix them when you don't know what is causing the problem, so go easy on the fertilizer.

How hot are the lights? To me, the leaves appear to have been burned. Particularly, the ones in the first pic.

Yellow leaves are typical of overwatering and/or poor drainage.

What kind of mix did you use when you potted them up? If your cups have drainage holes, it may be that your mix does not drain well.

I think if you solve the water issue, your tomatoes will be fine.

Betsy

Yes, the cups have 2 drain holes each. They are regular solo cups. They are just different colors, bought them at Sams Club.

I'm using Burpee seed starting mix. I looked and it does look as if it has very little fertilizer. I'm guessing I need a tomato fertilizer that I can mix in water? Why is it so hard to find! I've been to 2 nurseries this morning and they only have the slow release shake kind. Hopefully, I will find some soon and fertilize gently.

I'm not sure how hot the lights are. It doesn't seem as if any heat is coming from them. They are hydrofarm t5 lights.

Should I get them out of that seed starting mix and use something else, like a potting mix? Or just fertilize on top of what they are already in?
I pinched off some of the yellow leaves but that hasn't stopped more from yellowing. I haven't watered for a few days and it does seem like its holding moisture below the surface. Nothing much is draining out, but I don't add a lot of water when watering either.

While overwatering could be an issue, it also looks like ur plant needs fertilizing. It's about the size that requires fertilization to continue its growth. Be careful with fertilizing though, dry slow release fertilizer works well for me in the past or very low strength (less less less than half) liquid fertilzer or things like seaweed extract will work for now until the plant gets better.

Get them out of the seed starting mix. It is too fine to drain well in a larger container, it tends to compact and either stay to wet or be difficult to wet when it dries out completely.

Just be sure to use a soilless growing medium, not dirt from the yard or a bagged "garden soil" because it tends to compact in a pot and then it drains poorly and the tomato's roots will drown or suffocate and the plant will die. (Which is what I think is happening now.)

I don't think you need to feed them, since the nutrients in a regular growing medium should be sufficient to carry them the 8-10 before they are planted out into the garden.

I hope that helps.

Betsy

This post was edited by bets on Mon, Apr 1, 13 at 23:02

Funny, I thought I did everything right and a few of my leaves are beginning to yellow. The mix is excellent draining, but that doesnt mean that I'm still not possibly overwatering. Didn't think it was possible with a mega draining mix. Can't wait to get them outside.....no more than a week away. The next nice day they're going out! With protection of course, don't get nervous.