This is the first time I've tried growing basil from seed. I sowed the seeds about 3 weeks ago, and they started to come through about a week ago but they're looking kind of spindley. I've got them in a pot on the window sill, that I did have covered till they sprouted, then I left it off. They're now at the 2nd leaf stage, but they look so thin and weak. Is this normal? I was planning on hardening them off eventually and growing outdoors, but they just look so feeble??? The leaves are TINY - not even as big as my little finger nail