Store unwashed sweet potatoes in a cool, dry spot with good ventilation. Avoid refrigerating or storing sweet potatoes in plastic bags, which promote softening and sprouting. During the cool months of the year, I store sweet potatoes in my basement enclosed in a loose brown-paper sack with the top crumpled over but not sealed. This blocks out light but doesn’t trap moisture. During the warmer months, I buy just what I need for a recipe and use them right away. At 50°F/10°C, sweet potatoes will keep for a couple of weeks.