Is there a way to keep a room at growing temp when the room gets down to about 55 F? Even with the heat from like an hps, what about during dark hours? I wasnt sure if a portable heater would even be plant friendly? Its my only option during winter months up here in the northern midwest.
I use a small portable heater...it works. Switch your timer so the lights are on at night/morning when it's cold. Just give it some extra darkness when making the switch.