Dont think it would be a good idea to trying drying it at temps below freezing. Freezing the stuff is supposed to make the trichomes brittle and fall off when it gets jostled around. Know that from reading a bunch of hash making threads. I use several drying techniques including nose down in brown paper grocery bags, a big cardboard box lined wih newspaper, a perforated laundry basket or have hung them in the vegging closest if I wasnt currently vegging anything. Object is to keep them in the dark with some good airflow. Guess what I'm trying to say is there is all kinds of ways to dry the stuff out but none I know of which involves freezing unless your wanting to make hash out of it. Hope this helps.