Thanks everyone, The cold is probebly the major factor here, as I am growing in an unheated shed. Power usage makes it impossible to install a real heater in the unit, I was hoping that the heat from the lamps would prove sufficiant. I'm going to try a small fan/heater that I have directed at the plants to up the temps. I was under the assumption that cold (lows around 45 deg) would do nothing more than slow the growth rate. My ph test kit should arive in a day or two, then I could get a more accurate handle on the situation.

Thanks again for the input