Running a CBD tent in an unheated room through winter means the lights become the only heat source, and once they go off the temperature can crash into single digits and stall the plants. A small thermostat controlled heater or a heat mat under the pots keeps the root zone stable. The seasonal adjustment notes on https://calmcbdseeds.com recommend shifting the dark period to daytime in winter so the lamps run through the coldest hours. My winter yields improved noticeably once night temperatures stopped dropping below 16.
