My Plants did the exact same thing as well. It worked out in the end. I thought It was a heat issue at first like a burn from the light. I never really figured out what it was.

I used ProMix perhaps that was the problem. Somhitng in the Soil OR a PH thing.

I notice your Leafs all kinda hang down. Mine did too OverWatering? maybe

Hope somone can help us out..

kd