How Long Are Dry Dahlia Bulbs Good For?

Initial Planting Care

• Plant your dry dahlia bulbs, or tubers, in the spring when soil temperatures are higher than 60 degrees Fahrenheit. If you forget to plant the bulbs in spring, place them in soil as soon as you remember. Tubers do not survive outside of a medium for longer than their fall and winter dormancy period. These perennials do not need soil moisture immediately. Allow your planted tubers to remain relatively dry until you see sprouts emerge from the soil. Active growth indicates that the tuber needs water for continual development. Watering tubers before sprouting causes rot and failed flowering.

Overwintering Underground

• Warmer USDA zones 8 and higher provide protection from winter freeze and frosts. Your dry dahlia tubers are safe to remain planted outside as winter dormancy sets in. Maintain well-drained soil for the best tuber conditions. However, your planted location cannot be excessively wet. Tuber rot quickly kills any potential blossoms if puddles or wet soil persists; other pests and pathogens may infiltrate tubers as well. If your region is prone to wet winters, dig your tubers and store them until spring. Maintaining dry dahlias ensures a successful blossoming period next season.

Medium Storage

• USDA zones 7 and lower must dig their dahlias to preserve their future blossoms. After careful removal, dust any residual soil from the tubers and place them on a table for about 14 days. This drying period allows tubers to evaporate any remaining moisture from their bodies as they avoid rot. Add a slight dusting of sulfur to the tubers as well to avoid pathogen infiltration. Once dried out, place your tubers in a dry medium, such as sand or perlite, and maintain a temperature between 35 and 50 degrees Fahrenheit until spring planting season. Because of their dry condition, periodically observe their shape throughout the winter; excessive shriveling requires some watering to prevent dieback.

Plastic Wrap Storage Alternative

• Instead of storing tubers in a medium, wrap them in plastic wrap. After drying the tubers for two weeks, spray a fungicide across them to kill off any spores that may remain. Cover tubers individually with plastic wrap; they should not be wrapped and stored as a large bunch. Plastic wrap allows the tubers to retain their shape until spring without excessive shriveling that occurs in storage media.