wilt what to do?

i have beautiful well rooted clones, planted in soil mix, growing well for three weeks. moved to budding room and now 12hr lights and i am loosing about a plant a day to wilt. cant seem to get plants in budding room to grow. plenty of light leaves are green just one a day wilts and dies. i mist them daily not overwatering. i read about anti-wilt spray would that help at this stage? cant send photos old computer no camera. what am i doing wrong?
any suggestions.

how big are the pots they are in? sounds like could be rootbound... might need to repot ..just a though