Dark and cool, dehumidifier keeps it at around 50% or so, I just mist them and my dug bulbs (calla, caladium, elephant ears) to keep them from drying out too much. I've only lost them to the outside weather, never to the basement. I have enough window area to bring them out of slumber-time, so I don't use grow lights (plus, I'm cheap, er, thrifty). My house is sandstone covered, so I can leave anything out to a bit cooler weather if the days are sunny and they are next to the house. For a few weeks, the living room looks like a jungle, but otherwise, everything goes to the basement.
The gingers (cone, butterfly, blue and a yellow), along with some curcuma that took a serious frost in March have recovered fully and the curcuma are blooming now. I think that they're hardy to fairly cold temps for short periods.
