how far is the Hps from the plants? could be burning em up!! try movin it further away say 12" - 15" away from the tops..also now is a gd time to start nuteing its very pos that those baby are not going as gd due to lack/none things it can munch on!!(lamens terms) so give em a gd nutein with some orchid bloom, or any kind of blooming material you can get from the local GC...