You dont say how cold in degrees ,but around 50 and lower growth is slowed considerbly. They should recover fine when you can get them in warmer temps. Can you put them in front of a sunny window ? Are these in separate cells/containers ?

Thanks dickiefickle--
The temp probably went well below 50, as it got quite cold outside. The only place I have to keep them is in this uninsulated sunroom. It has worked ok in the past but this year's weather was much colder.
I'm relieved to hear you think they will most likely recover. They are currently in individual seed cells but I was going to transplant them to larger cups for a couple weeks before planting outside. Why do you ask?
Best,
Roni

I compared your pics to these others on this website from Cornell University; it has an extensive list of possible causes. I wasn't able to locate anything that looks exactly like your problem. Is the distoloration on the bottom of the leaf also? You could try wetting one end of a Q-tip and supporting the underside of the leaf with a finger or two, gently rub the spot to see if it transfers or comes off. My thoughts are either a mineral in the soil, or fungus; most likely fungus. If the condition - coloration, saturation, location -changes or migrates to the stems, I'd pay a visit to your local AG extension office; they are your best bet. You might try placing a small fan in the environment to improve air circulation. One last thought, is your soil aerated well? If your potting mix is too dense next time be sure to mix in about 20-30% of Vermiculite to ensure good soil drainage and aeration. This will also produce better conditions for root growth. You may want to treat using a multi purpose fungicide that contains neem oil, but not a sulfer powder.

Blessings!

Here is a link that might be useful: Tomato Leaf Symptoms

I'm having the same issue. I have seeds in the same room I've had them the last two years. I'm using the same two grown lights. The only differences are I used Miracle Gro Seed Starter (I had used the pellets before with decent success) and some of the seeds were leftovers from last year (but not all). I was told by a friend the seeds should still be good, and they did sprout. I planted just under a month ago and just now - a few (out of 100 or so seedlings - two seedlings per 50 cells) are just starting to get their first true leaf. I've already transplanted peas, cucumbers and squash (I understand things mature at different speeds), but this just seems extreme. I'm at a loss as to what or why?

I'm so glad someone else posted about this! My seedlings are the exact same and I'm worried they won't be ready to plant outside in a few weeks :(

I started a thread a few weeks back. Here's the link.
http://forums.gardenweb.com/forums/load/tomato/msg0423531626701.html?10

Mine are 6 and a half weeks old and MAYBE 4 inches tall, but most are still only a few inches tall. Goodluck with yours, let us know if you find the secret to fast growth.

I had a similar problem last year. I started my seeds on heat and after they sprouted, I pulled them off the heat (as, generally, recommended.) They only got to be about 4 inches in the 6-8 week period before putting them out. They never did do well last year, however, it was a poor tomato growing year in my area.

This year I left them on heat for a couple of extra weeks before taking them off. The difference was huge. I had to pot them up several times and they are now in WOWs in the garden.

Heat will get them going.