That sounds like you've overfed them...but check out this guide and compare:

http://www.drugs-forum.com/growfaq/951.htm

Oh and HAMMMER SMASHED FAAAACE! What a fucking tune!
Zoidberg Reviewed by Zoidberg on . Help please One of my plants have darker green leaves, and they're curling under and twisting. is this because i have over watered them? Rating: 5