Seedling's leaves are curling

Well these two seedlings have been growing for about 5 days now and one of them has curled leaves. Am I doing something wrong?

Curvy-leaved one:



More normal one:

are you maybe a little heavy on the water lately

oh, and since this are plastic cubs, did you drill holes into the bottom of these so that the water can drain from them, if not you are drowning your babies roots until they rot on you!

They both have holes for drainage, but I've only been watering them a little bit around the stem every 1-2 days as you may be able to tell from the photos if you look really closely. Could it be nothing, or is there most likely a small problem developing here?