Maybe use an HID bulb instead of the CFL's?
canniwhatsis Reviewed by canniwhatsis on . Grow box - cold temps Box is in uninsulated outbuilding with no heat.... no other options due to security issue and too impatient to wait for another summer... cold temps are making this a real nightmare.... october to december-ish grow... temps during that time range from 0 degrees F to 50 degrees F. CFL'S for lighting.... computer fan on top for exhaust with passive intake on bottom... small computer fan inside the box to provide air movement inside... box is insulated with sterofoam but still too cold. I Rating: 5