Most of my outdoor growing was done when I lived in SF and I never had any problems but then again I was usually harvested by now to beat the rainy season. You might try some foam insulation on the inside walls of your grow cab...you can buy it in 4 x 8 sheets in different thickness...1", 1.5", etc.

These days I get nervous when my temps get below 65 but I am spoiled rotten by the weather here in Socal.
doco Reviewed by doco on . Lowest temps at night? My outside cabinet grow is ready to go into 12/12. I would rather have the lights on during the day, which would keep the closet at 75 degrees +/- 5. The night time low is around 45, and hardly ever gets in the thirties. Would the night time temps harm my plants in any way? My understanding is that as long as it does not reach freezing, my plants should be ok during no light period (night). Is this correct? PS: I live 35 miles NE of San Francisco. BHG Rating: 5