i suck at this

Clear containers are a bad idea. Light is not pleasant for roots. Also make sure you have plenty of drainage holes in the bottom. If you don't, you will suffocate the roots. The droopy ones that are yellowing appear to be having an overwatering problem. Luckily, as long as you have good drainage, overwatering won't be a huge problem in coco. Even saturated, coco holds a good amount of oxygen. Your plants don't look too bad for 15 days, but they'll need bigger pots very soon. If they're autos, it's better to start them off in their final pot as autos hate to be transplanted. Don't give any NPK nutes until those little round leaves start dying. Hope this all helps!