Storing Non-hardy Rhizomes, Tubers and Corms
Keep your tropical bulbs from season to season with a bit of special winter care.
Carefully dig or remove the plant from its container after the leaves are killed by a light frost or have turned yellow. Spread the rhizome, corm, tuber or bulbs on a paper covered table or better yet a screen and place in a warm dark location to cure.
Dahlias are ready to store in a couple hours, cannas need to cure overnight while gladiolas need several weeks in the warmth.
Once cured, remove any remaining foliage and gently brush off the soil. Then place the bulbs in a shallow container filled with peatmoss, vermiculite or sawdust and cover completely. Label and move to a cool dark location about 45 to 50 degrees for the winter.
Store gladiolas uncovered in a mesh bag in the same cool dark conditions.
A bit more information: Don't pack your tuberous begonia away for the winter. Grow it as a houseplant. Move your potted begonia to a warm sunny location. Water thoroughly and often enough to keep the soil slightly moist. Avoid drafts of hot and cold air that can cause leaves and stems to wilt and discolor. Give the plant plenty of room to grow. Overcrowding reduces light penetration and air circulation increasing the risk of powdery mildew. Wait until the plant show signs of growth before fertilizing with a dilute solution of flowering plant fertilizer. I know several gardeners who have kept their tuberous begonias for 5 or more years using this method.