Growing

I've just recently fucked up on some seeds that just sprouted, I'm pretty sure the reason why the leaves were curled up was down to over watering them, but is there any other reason they might of done that. Have just put in three new ones and they are growing fine, been growing for nearly 3-4 days and no curling, is that because I've controlled the amount of water their getting and not over watering them?

IDK usually over watering causes leaves to droop, not curl up. U are not feed nutes already? What is the PH of the water ur using? Do u have any pics that would help