That would be a good guess. ;-) It's the most likely cause.

Dave

I like your cell packs. Just pop that plant out and look at the root mass and media moisture. Plants can also be at the growth stage where they are becoming root bound. It may be time to pot up.

You mention the lights but are plants also nearby to a window where direct sunlight can hit them? That could also cause drooping as plants adjust to it.

Those plants are getting large for those cell packs. They are certainly root-bound. I'd pot them up or get them in the ground asap. That should be a bigger worry than drooping leaves.

Thanks everyone for your replies!

Just a bit of background....I started the seeds in Jiffy peat pellets (the small size) and the seedlings outgrew the pellets so I decided to transplant them into the cell pack. The pictures make the plants seem larger, but they're about 4 inches tall and I'm hoping that I can keep them there until I can plant them out. I live in Montreal, Quebec and we still have snow on the ground. I popped one of the plants out to check the roots (picture below).

My plan as of now is to hold back on watering a bit and hope that the leaves perk up. Also, I'm reconsidering keeping them in the cell pack. Should I move them into solo cups or something bigger?

Thanks again!

You won't be planting out for a few weeks yet (last frost is end of the month) and, by then, your plants will be getting too big for even the size of a solo cup. But fill the cups well, and when you plant out, if you bury the stem deeply, you should be OK. You planted your seeds pretty early. I might suggest that you find a place for them where the temperature is a bit cool. That will slow them down without hurting them.