Tuberous begonias have tender roots that won’t survive the winter in areas that experience hard frosts. Dig up and store the tubers over winter so you can enjoy them again next year.
Dig begonia tubers after the foliage is injured by a light frost. Loosen the roots by carefully digging around them with a garden fork. Take care not to injure the tubers. Injuries are an entry point for diseases during storage.
Leave the soil on the tubers and allow them to cure in a well-ventilated area out of direct sunlight for two to three weeks. Keep the temperature between 60 and 70 degrees Fahrenheit. After curing, brush off any soil that clings to the tuber.
Store the tubers in a cardboard or wooden box between layers of dry peat moss, sand or vermiculite. Store the box at temperatures around 40 to 45 degrees. Use a powdered fungicide to protect the bulbs during storage. Choose a product labeled for bulb storage and follow the instructions carefully.