I’m using a shack to grow my marijuana using hydroponics for some and containers with soil for others. The shed is completely uninsulated and outside temperatures get into the 30’s in October and 20’s in November. Is it possible to use heating cables to help maintain higher temperatures in the water or the soil? How cold does it have to be for the marijuana plants to start showing adverse effects?
Maturing marijuana plants can handle temperatures as low as the mid-40’s without incurring any tissue damage. But, they can survive a brief dip into the 30’s even if it requires a few days for them to recover. Is there something preventing you from insulating the shed?
You could also turn the lights on at night instead of during the day. That allows the shed to be heated by the sun during the day and the lights at night. It’s also a good idea to heat the roots in cold weather to keep the plants healthy. With heat cables, heating mats, and water heaters, you can maintain temperatures of around 80*F. The upper section of the plants can take one temperatures 5 to 10 degrees lower than normal.