How to store dahlia tubers correctly in 6 easy steps
Ah, dahlias! With their brilliant, eye-catching beauty, these blooms are true show-stoppers, creating a vibrant spectacle in the garden all season long. I am in love with them! And in the last month of fall, I am still blessed to cut some dahlia flowers for our home.
As the final blooms of fall fade, it’s bittersweet to know that their time is ending, and I now need to lift the tubers out of the ground for overwintering.
But with a bit of care, these tubers can be stored and brought back next year to flourish once again!
Here’s your step-by-step guide on how to dig up and store dahlia tubers properly so they thrive for years to come.
Contents:
Why You Need to Store Dahlia Tubers
Dahlias are native to Mexico, so they’re not particularly winter-hardy. If you live in a region where the ground freezes in winter, leaving dahlia tubers in the ground could lead to them freezing, splitting, and eventually rotting.
To prevent this, you must lift and store your dahlia tubers until the next planting season.
However, if you live in a mild climate without freezing temperatures, you can leave your tubers in the ground, and they may return year after year.
While digging up your tubers might seem like a hassle, the good news is that with the right care, these tubers can be safely stored and replanted each spring, providing you with a continued supply of stunning flowers for years!
When to Dig Up Dahlia Tubers
Knowing when to dig up your Dahlia tubers is crucial.
Colder Climates
In colder climates (zones 7 and below), you need to dig up your dahlias before the first hard frost hits. Ideally, the plant should have finished blooming and its foliage should begin turning yellow and dying back. This indicates that the plant is ready to go dormant and that it’s time to dig up the tubers.
Be sure not to dig them up too early—let them stay in the ground as long as possible without freezing. The longer the tubers stay in the soil, the healthier they’ll be. The roots need time to “cure” and store up energy for the next season.
Mild Climates
If you’re in a borderline zone (like us in zone 7 B), a light frost won’t harm the tubers, but make sure to wait until the ground is slightly colder and the foliage has naturally died back.
One thing I have done and has worked okay in my zone is to wait until it freezes. This means that there is usually a mild frost that kills the dahlias before we get the true freezing weather. I cut the tops and let them sit in the ground for another week or two. This allows it to gather energy for next year. Then I lift from the ground and follow the steps below.
I have also left tubers in the ground before with no issues. We have raised beds, which I believe helps!
Warmer Climates
In warmer climates with no freezing temperatures, such as parts of the Southeast and Southwest, you can leave your dahlias in the ground to overwinter as perennials. Lucky you!
See down below for my steps on how to store Dahlia tubers in winter.
How to Store Dahlia Tubers
Step 1: Cut Back the Stalks
Once the first frost has killed the foliage, it’s time to cut back the stalks. Use pruning shears to cut the stems to a few inches above the ground. If you want the tubers to divide more easily later on, you can cut the stalks a few days before you dig them up.
To protect the tuber necks from water infiltration (which could cause rot), cover the cut stems with foil or a similar protective cover until you’re ready to lift the tubers. Additionally, it’s important to disinfect your tools before and after each cut by dipping them in a 1:10 bleach-to-water solution. This helps prevent the spread of plant diseases between your dahlias.
Step 2: Carefully Dig Up the Tubers
Using a garden fork or shovel, carefully dig up the dahlia tubers, starting about 12 inches away from the base of the stem. Be careful not to damage the tubers or the roots, as they are fragile at this stage. Once you’ve loosened the soil, gently lift the tubers out of the ground.
If you can, let the tubers sit in the ground for a few hours to harden off and allow the necks to dry slightly. This can help prevent damage and minimize the chance of rot.
Step 3: Clean the Tubers
Shake off excess soil from the tubers and rinse them gently with water to remove any remaining dirt. Be sure to wash them thoroughly, as any dirt left on the tubers can harbor harmful bacteria and fungi that can lead to rot during storage. If you notice any rotten or damaged sections, cut them away to prevent the spread of decay.
Step 4: Divide the Tubers (Optional)
If your dahlia tubers have multiple eyes (the small growth points that will sprout next year), you may choose to divide the clumps now or wait until spring. I have done both methods. Decide what is best for you. If you do divide them, use a sharp knife and cut through the tubers so each division has at least one eye.
The eyes of dahlias are the set of cells that produce the next season's plants and blooms. They almost look like pimples! If you can't identify them in the fall, wait until the spring to divide your tubers, as they may be more visible by then. This is why I will usually just wait.
Inspect each division carefully for any signs of damage or disease. Remove any parts of the mother root that are decaying or damaged. After dividing, rinse the tubers again to remove any leftover soil.
Step 5: Let the Tubers Dry
After washing and dividing, it’s essential to let the tubers dry for several days, or even weeks, before storing them. This drying process allows the tubers to cure, helping to prevent mold growth.
Place the tubers in a warm, dry spot with good air circulation, but keep them out of direct sunlight. A dry, cool area with temperatures above freezing is ideal for drying. The tubers are ready to be stored when their skin starts to wrinkle slightly, indicating they’ve lost enough moisture.
Step 6: Store Your Dahlia Tubers
Once your dahlia tubers are fully dry, it’s time to store them for the winter. The ideal storage temperature for dahlias is between 40 and 45°F (4-7°C). A cool, dark, and dry location such as an unheated basement, attic, or garage works well. Avoid places prone to moisture or mold, as excess humidity can cause the tubers to rot.
To store the tubers, place them in a container like a crate, plastic bin, or cardboard box. To prevent them from touching each other directly, use a material like coarse vermiculite, sawdust, or peat moss to separate the layers. If you’re using a cardboard box, you may want to line the sides with newspaper to help absorb any excess moisture.
Be sure to leave some ventilation between the tubers to avoid creating a humid environment, which could encourage mold. Check your stored tubers once a month for signs of rot or mold, and discard any affected ones immediately to prevent the spread.
Extra Tips
Label your tubers: If you have different dahlia varieties, be sure to label each clump so you can easily identify them when it’s time to plant again in spring.
Avoid overwatering: When storing your tubers, it’s important to keep them dry. If you notice any tubers shriveling, mist them lightly with water, but avoid soaking them.
Rotate your storage containers: Occasionally, rotate the containers to ensure even air circulation and prevent moisture buildup at the bottom.
Getting Your Tubers Ready for Planting
When planting time arrives in the spring, it’s time to wake up your stored dahlia tubers and prepare them for another season of beautiful blooms! Here’s what you need to do:
1. Inspect the Tubers
A few weeks before you’re ready to plant, take the tubers out of storage and inspect them closely. Look for any signs of rot, mold, or shriveling. Discard any tubers that are soft, mushy, or appear decayed, as these won’t thrive in the garden.
If you notice any tubers that have shriveled slightly but are otherwise healthy, you can rehydrate them by lightly misting them with water or soaking them in room-temperature water for a few hours. This can help them plump up before planting.
2. Divide the Clumps (if not already done)
If you didn’t divide your tubers in the fall, you can do so now. Each division should have at least one visible "eye," which is the small bump or growth point that will sprout into a new plant.
Use a clean, sharp knife to divide tubers, ensuring each section has one or more eyes. Be careful not to damage the eyes, as this is where new growth will emerge.
3. Pre-Sprout the Tubers (Optional)
Pre-sprouting is a good option if you want to get a head start on the growing season, especially in cooler climates. To pre-sprout, place tubers in shallow trays or pots filled with damp potting soil, sand, or vermiculite.
Keep the trays in a warm, bright spot indoors, ideally around 60-70°F (15-21°C). After 2-4 weeks, you should see shoots emerging from the eyes, which means they’re ready for planting.
4. Choose a Planting Time
Wait until all danger of frost has passed and the soil has warmed up to around 60°F (15°C). Dahlias are frost-sensitive and will struggle in cold, wet soil, so patience is key.
In most regions, this means late spring, around April or May, depending on your local climate.
Storing dahlia tubers can seem daunting at first, but with these steps, you’ll be well-equipped to keep them safe through winter. Come spring, they’ll be ready to return to your garden, bringing their dazzling blooms with them.
May your precious dahlias survive this winter and come alive again next season!
Love, Annette xx
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