How to Dig, Divide & Overwinter Dahlias

Once the first frost hits, it's time to begin preparing your dahlias for winter. Whether you're storing tubers for personal use or preserving your favorite varieties for next season, a few simple steps will ensure healthy, viable tubers come spring.

When to Dig Up Dahlias

Wait until a hard frost blackens the foliage. This signals that the plant is done for the season and helps the tubers begin the dormancy process.

Cut the stems down to 4–6 inches above the ground and wait 5–7 days after frost (if weather allows) before digging. This lets the tubers begin to cure naturally in the soil and helps toughen their skins for storage.

How to Dig Up Dahlias

  1. Use a garden fork or shovel to gently loosen the soil about 12 inches from the base of the plant.

  2. Carefully lift the clump, keeping the tubers attached to the crown.

  3. Brush off excess soil—do not wash if you're curing before dividing.

  4. If you haven’t done so while in bloom, label the variety immediately with a waterproof tag or painter’s tape around the stem.

Dividing Dahlias (Can be done in fall or spring)

Dividing in fall allows more airflow and saves storage space. However, if you're unsure about identifying eyes (growing points), it's perfectly fine to wait until spring.

To divide:

  • Rinse tubers with water to see the shape and identify the eyes.

  • Let them dry for 12–24 hours.

  • Use a sharp, clean knife or snips to cut tubers away from the crown. Each division must have at least one visible eye, part of the crown, and an intact neck.

  • Optional: Dust cut ends with sulfur powder or cinnamon to prevent rot.

Storing Dahlia Tubers for Winter

Dry and Cure:

  • Let tubers dry in a cool, well-ventilated area (40–60°F) out of direct sunlight for 24hrs (max 48hrs).

Pack for Storage:

  • Store tubers in peat moss, wood shavings, vermiculite (my preference), or shredded paper inside cardboard boxes or plastic totes with ventilation holes.

  • Keep storage temps between 40–50°F. Avoid freezing!

  • Check monthly for mold or shriveling—remove any soft or rotting tubers.

Come spring, your stored tubers will be ready for planting—strong, healthy, and ready to bloom again. A little post-season care goes a long way in protecting your dahlias for years to come!