garage grow over winter to cold?

so i would like to grow in a enclosed custom made plywood box and my garage gets cold in the winter sometimes below freezing and i was wondering if i insulate it with the sheets of soundproof stuff or the rolls of the reflecting insulation.. would my plants get to cold and die or would it be ok with the light on 18 hours or so a day to heat it..if anybody knows if they can survive in a box in cold weather please respond thanks!

i'd think that if the box was well insulated they'd do fine so long as they lights were on.. when they go out would be a different story all together though..
i'd think you could rig up some sort of space heater to keep temps inline 24/7 though.. it make take a bit of tinkering around on your part to get temps set and maybe use some timers and adjusting the on / off times of the heaters, but i think you could easily pull it off..

check under general growing there is a thread on cold set up, it looks so good for under 100 bucks. https://www.rollitup.org/general-marijuana-growing/569226-ez-cold-weather-grow-room.html

Use those foam sheets to insulate..

Mind telling us some temperature readings outside the house, inside the garage, and inside the box with the light on, and with the light off? Until you have those numbers we can't speculate at much...