That was one, convoluted process! I originally put them between the screen & storm window. But it wasn't cold enough for them and they were still growing. That and a bit of "greenhouse effect". Then I moved them to the screened in porch and we had a cold snap for several days. The soil froze, briefly. Then I had them in the butter keeper of our fridge, until February. Then I put them on the cold window sill of the lab, easing them back into warmer temps. I did nothing special to them, only what was annoying. I neither covered them, nor sprayed with fungicide. They were still "open tray" and kept barely wet. I think that by being open tray, in a fridge with a circulating fan was what kept them from molding. This past winter I put my VFT's & Sarrs in a plastic tub, open tray, in the fridge at the lab. One Sarr. died, but all else survived - only to be carried off in one of my stream experiments gone awry.