looks to me, its over watering & too much nutrients! Just leave them alone for a bit, new green will grow out, most those curled up leaves will die off since its still early. Also your pot is way way too big for that plant, you might be better off getting faster green growth by transplanting into a smaller pot. The roots will have a better chance of getting the nutrients they need with out heavy watering. Just in case I would sow some new seeds, get them going now.