Christ , if I was that keen to grow abit of weed in those temps I would use underfloor heating on every wall , ceiling and roof plus kingspan . Cost a lot of coin mind
Just working with that I have no need to be condescending... Going to draw warm air passively from inside using my T6 and have my totes off the floor and run a space heater on an inkbird ill be fine without spending too much... I'll have blankets to insulate the reservoirs but if my plants die they die. my totes are HDX so they should be able to handle a night or two of ice in worst case scenario.