Remove dahlia bulbs aka tubers from the ground before the first frost.
Using gardening shears, cut the dahlia stems close to the ground (about 4” above).
Discard the plant.
With a shovel, dig around the dahlia roots giving yourself plenty of clearance to not damage any bulbs.
Gently lift up the soil along with the dahlia bulbs.
Gently shake off the excess dirt and place the dahlia bulbs with dirt in a protected space to dr such as under the edge of the deck or against the house.
If you have plenty of assorted dahlias, sort them by size and color and keep note of which is which.
After 2 weeks, gently break apart the dirt in between the bulbs and roots.
Inspect the dahlia bulbs for damaged, cut or rotting bulbs. Remove any that are damaged and throw away.
Pack the dahlia bulbs upside down (with the stem side down and root side up) in a dry cardboard box.
Cover the dahlia bulbs with newspaper, peat moss or wood shavings.
Label the box with the size and color of the dahlias.
Store the box in a dry cool place such as an insulated garage, seller room until Spring.