Is there something I can put on my potatoes to keep them from sprouting over winter?
There is nothing home gardeners can put on potatoes to keep them from sprouting. The keys to successful storage of potatoes are the proper temperature and relative humidity.
Before placing the potatoes in storage, cure the tubers at a temperature of 50 to 60°F and relative humidity of 85 to 90 percent for two weeks. The curing period allows minor cuts and bruises to heal and the skin to thicken on the tubers.
Once cured, store potatoes at a temperature of 40°F and relative humidity of 90 to 95 percent. The storage location should also be dark as potatoes turn green when exposed to light. The potato tubers may begin to sprout in 2 or 3 months if storage temperatures are above 50°F.