Winter Zombie

Flowering cycle engaged since 2 weeks, no really flowers for now. Growth seems over. Starting slowly… The problem for now is this freezing winter. Low temperatures around the grow tent: 11 degrees at night; I placed some cardboard around (better than nothing), the little ceramic heater is still on and the light produce some heat too. But when the air extractor is on, during 15 minutes every 2 hours: temperature inside the room fall and it take some time to recover a stable and correct conditions. I must buy an extractor with adjustable speed or less power; but for the moment I can reduce the frequency of air extraction but I don’t know the limits for the plants. I placed a carbon filter: it will be essential for discretion in a few weeks. This sytem offers a sort of isolation around the air extractor: not bad by this time. 2 x 50cl Watering: every 3 days with rain water + Fish Mix.