Dahlias, with stunning blooms in a wide range of colors, sizes and textures, are a delight in the late summer flower bed. Native to Mexico, dahlias thrive as long as they are planted in a sunny spot, in soil that drains well. Although dahlias don't require a great deal of care, dahlia tubers won't survive freezing weather. If you live in a climate with cold winters, dig the tubers after the first freeze, and store the tubers safely until they can be replanted in spring.
Dig dahlias after frost has nipped the top of the foliage. Use garden shears to cut the foliage back to about 6 inches from the ground.
Insert a garden fork into the soil about 6 inches from the plant. Rock the fork back and forth to loosen the dahlia tubers, then continue working around the plant. Once the tubers are loosened, lift the plant from the ground with the fork.
Brush the excess dirt from the tubers with your hands. Don't rinse the tubers with water.
Spread the tubers on a flat surface in a cool, dry room, and allow the tubers to dry for about two weeks. When the tubers are dry, dust each dahlia tuber with powdered sulphur to protect the tubers from disease and pests during the winter.
Fill a cardboard box or a paper sack with peat moss, sawdust or dry sand and bury the tubers, not touching. Store the tubers in a cool room in temperatures between 40 and 45 degrees Fahrenheit. Don't allow the tubers to freeze. Inspect them every three weeks.
Discard any rotten, bruised or moldy tubers. Place any shriveled tubers in a bucket of water overnight, then lay the wet tubers on a flat surface and allow them to dry thoroughly before returning them to storage.