Dahlias are a delight to grow every summer—a celebration of captivating colour and natural beauty. But in order to ensure that next summer’s carnival is as splendid as this year’s, it’s imperative to provide proper winter care for your dahlias. They are susceptible to frost. In areas where the ground freezes during the winters (Zones 3-7 in particular), storing and lifting dahlias is essential through the period of cold. The following information will help your dahlias survive and make a grand return next season.
When to Lift Dahlias
It’s safe to dig up your dahlia tubers once the plants begin to turn brown and die back. This is usually about two weeks after a killing frost. It’s okay to wait until after the first hard frost, but don’t leave the tubers in the ground for a long period of below-freezing weather.
Digging Up Dahlia Tubers
Start by cutting back the foliage, leaving only a couple of inches standing above the ground. Use a pitchfork or shovel to dig around the tubers, maintaining a safe distance to make sure you don’t damage the roots. Lift the tuber out of the ground and gently shake it to remove excess dirt. Follow suit with all the dahlia tubers.
The tubers will require further cleaning before they’re ready for winter storage. You can use a garden hose or a tub filed with water to wash the dirt off the tubers. Be gentle as you rinse the tubers for any damage caused to their skin can lead to rot during the storage period.
Inspecting and Drying the Tubers
With the tubers all cleaned up, it’s time to carefully examine every one of them. If you find any rotten parts, cut them off with a clean, sharp knife. Use paper wipes or tissues to gently wipe the tubers and spread them out to dry on a newspaper or dry sheet. Any location away from direct sunlight and with good air circulation will suffice for drying the tubers. Just make sure the night temperature doesn’t drop below freezing in your selected spot. It’s best to allow the tubers several weeks’ time to completely dry up before storage.
How to Store Dahlia Tubers Over Winter
Finding a storage spot that delivers the right conditions can be tricky. It should be dark and dry, with good circulation and zero risks of freezing during the winter. You may use cardboard boxes, paper bags or even empty milk cartons to store the tubers. Plastic bags or plastic containers that are sealed should never be used for storage. Layer the tubers with a storage medium such as slightly dampened peat moss, sand, sawdust or wood shavings until the container is full. Label and then place the containers at a little distance from one another to allow for air passage. Store in a cool, dry area, at a temperature between 40°-50°F. If conditions are too cold, the tubers may freeze and could rot; too warm, and they could dry out and shrivel up.
When to Bring Dahlias Out of Storage
It’s hard to be patient once the first signs of spring appear. However, it’s essential that you wait until there’s no risk of a last, surprise frost in spring to bring dahlia tubers out from the storage and replant them. Once the soil warms up (to at least 60°F.), you may replant the dahlia tubers, or start them indoors about six weeks before you intend to plant them outside.
