Suzanne said:

Another thought is that I took the plants outside yesterday and today
for a few hours. They have grown under shop lights exclusively but I
thought they might enjoy the nice weather. Would this have anything to
do with their problem?

A few hours in a sunny spot? That might be enough to sunburn some
tender leaves. The seedlings need to be gradually acclimatized to full
sunlight. I usually place them where they will get indirect light or dappled
shade the first time they go out, then place them farther and farther ahead
of the shadows.


Indoor plants will also need shelter from the wind when they first go out.
I run a fan on my seedlings while they are indoors. The air circulation is
good for them and the breeze helps toughen them up a bit.

--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)