Roof Dry Technique During Winter?

Hey got a sweet harvest, concerned with how i am going to dry it as what is available to me is limited, i can either put them in a roof at my residence and limited amounts of cupboards or attempt an outdoor dry. Usually the rooftop would be a no brainer, but the temperature can get pritty low where i aqm throughout winter with night temperatures being steady around 15 celsius, thought this might be a problem, further i have previosly tried a roof dry by placing the buds in a box inside the roof, but the buds stayed pritty moist and slight white mold began to appear, what should i do?

Welp, that's a problem. Neither of those is an option without some form of constant temp control. If you truly have no other option, then build a box in the attic out of plywood and insulate the exterior with foam board. Put in a small electric space heater with thermostat (preferably ceramic) and go that route. The box would have to be twice as tall as necessary to allow the heater to run on the floor without drastically heating up the branches hanging above.