The plants need full sun exposure. My guess is they are not getting enough direct sun.

I also wonder if they are getting enough nutrients. I would give them a shot of N and see if they perk up.

That said, I have had some things just sit there as well this year because of the cold.

Thanks for the responses! They were getting full sun during the day in their containers but I moved them to a spot where they should get even 2-3 more hours of sun to see if that helps.
I also wonder if the soil they are in is not nutrient rich enough and will fertilize them soon once it warms up slightly.
Z

Hmmm.... just past the cotyledon stage, they shouldn't really need that much nutrition. I'd guess more of a sunlight or soil texture issue. Is the soil fine and fluffy or dense, heavy?

While I doubt it's lack of nitrogen at this stage, no harm in feeding them lightly. (I'd sprinkle liberally with coffee grounds and water in).