How to Dig Up and Overwinter Dahlias: Step 1
If you live in Zones 2 to 8 and want to keep your prized specimens blooming year after year, you can dig them up and keep them in a cool, dry spot. Follow the steps below, and you'll have tubers ready for planting come spring—and likely a few extras to share with friends.
Cut off the stalks two weeks after the first hard frost. Leave roughly 6 inches of stem intact. Use a shovel or a pitchfork to gently lift the tubers from the ground, being careful not to break their stems.