Dig and Store Dahlia Bulbs for Winter

When fall rolls around, gardeners begin the task of digging and storing tender dahlia bulbs for next year's blooms. Although the process is relatively simple, it is vital to the success of next summer's flowerbed.

Wait Until After the Frost to Dig Dahlia Bulbs

Dig dahlia tubers, commonly referred to as bulbs, in the fall after the frost has killed foliage. If planted in a sheltered location, dahlias may bloom well into the fall adding color and beauty after many summer blooming flowers have faded. Although the foliage is tender, bulbs are not damaged until the soil freezes, so don't hurry these beauties and wait until nature takes its course.

Cut foliage back to 4 to 6 inches from the ground once foliage is killed by frost. Tie a tag to the stem indicating the type of dahlia and its color to prevent confusion in the spring. You may think you will remember which bulbs are which in the spring, but chances are you won't.

Use a garden spade or garden fork to dig around the base of your dahlia plants. Begin at least a foot from the main stalk as dahlia bulbs spread under the soil and can cover a wide area.

Slide the fork under the bulbs and lift the entire clump free of the soil.

Shake to remove excess soil from the clump of tubers. Use a hose to spray the roots to remove remaining soil.

Place the clumps of dahlia "bulbs" upside down to dry in a cool dry area. Bulbs can be dried outside, but should be out of direct sunlight. Placing them upside down allows moisture in the stem to drain. Allow to dry for 24 to 48 hours.

Layer 2 to 3 inches of perlite or peat moss in the bottom of a cardboard box or wooden crate. Place the dahlia bulbs in the peat moss. Fill in around the bulbs with peat moss or perlite covering the bulbs with 3 to 4 inches of peat moss.

Mist to moisten the peat moss or perlite. It should be lightly dampened, but should not be soggy. Moisture promotes mold and may introduce disease.

Cover and place the box in a cool dry area. The University of Colorado Extension recommends temperatures between 40 and 50 degrees Fahrenheit. Any unheated area of your home is fine, as long as the temperatures do not dip below freezing.

Check bulbs every few weeks for signs of shriveling. Mist to increase moisture if bulbs shrivel. Too much moisture may cause bulbs to rot. Remove any discolored or moldy tubers and reduce moisture if mold becomes a problem.

Separate and plant dahlia bulbs in the spring once the danger of frost has passed in your area.

University of Colorado Extension: Storing Dahlia Tubers
UC Davis: Spring Planted Bulbs, Corms and Roots