If it is overfertilization, just water heavily enough to drain out the bottoms of the trays a couple times to flush out the excess, and they should recover (unless you dumped a whole box of dry chemical ferts on there!).

I wonder if it could be something else though, it's hard to tell without seeing a picture.

dirtmonkey, I have discovered my terrible error. Unbeknownst to me I was using soil that had fertilizer in it thinking it had not! I shall follow your suggestion and hope for the best. Think getting them in the ground would also be a good solution, but we are expecting frost this coming Sunday. Tks again.