After your beautiful dahlias have finished blooming in fall, consider digging up the tubers to perpetuate your dahlia plants for seasons to come. This important process helps to protect the tubers over winter, as well as expand your stock. Learn how to dig dahlia tubers, to keep them safe and snug until they can be planted out again the following spring.

Getting Started
If you live in zone 6 or below, digging up your tubers in fall will help to protect your plants from the devastating effects of freezing over the winter. Dahlias will not recover and will rot if exposed to sub zero temperatures and become frozen.
If you live in warmer zones (USDA plant hardiness zones 7 and above), the dahlias do not necessarily need to be dug, as long as they are protected from freezing. However if you lift and divide them, even in these warm zones, you can refresh the plants and keep the healthiest tubers.
Digging and dividing dahlia tubers is important for maintaining healthy dahlia plants. It can also help with successful propagation of your dahlias, so that you can grow more of them, year after year in your garden.
Preparing For Digging
Timing
The best time to dig the tubers is after the first or second hard frost, when the foliage has become blackened. I will often wait a week or two after this occurs, to allow the tubers to cure under ground.
The curing process helps to toughen the outer surface of the tubers, making them less vulnerable to trauma and disease.
Harvest on a dry day if you can. Dry soil is easier to lift, and labelling the plants is almost impossible in the rain (been there, done that).
Tools Needed
- garden fork or spade
- pair of pruners
- gloves
- storage containers for the tubers (milk crates, cardboard boxes)
- plastic ribbon and permanent marker for labeling
Preparation Steps
Trim back the foliage and stems to approximately 4 inches above the soil surface. This makes the process easier, and the stems more visible.
Clear the area around the plant for ease of digging.
How To Dig Dahlia Tubers
- Gently loosen the soil around the plant with a garden fork or spade, approximately a foot away from the stem.
- Some tubers can be quite large, and can be damaged if you dig too close to the plant.
- Carefully lift the clump of tubers, avoiding cuts or bruising.
- Carefully remove the excess soil. Try not to shake the clump in an attempt to remove the soil, as this can damage the delicate tuber necks.
- Inspect tubers for rot, damage, pests, or disease.
- Tubers with broken necks should be tossed. Tubers that have been accidentally damaged or cut through during the digging process may be salvageable, as long as the neck and crown are intact.
- The wounds can heal as the tubers dry and cure.
- Label each clump as it is dug, so as not to mix up different cultivars.
- You can leave some soil on the tubers to prevent them from drying out, until you are ready to clean and divide them. Dividing the tubers does not have to be done on the same day that they are dug.
- Store in a cool space until ready to be washed and divided. Make sure that the tubers are not exposed to frost in the storage area.
Dividing The Tubers
Properly dividing and storing dahlia tubers offers several benefits that directly contribute to beautiful, healthy blooms in future growing seasons.
Why Divide
Division is a great way to turn one plant into many more, and a great way to propagate your favorite dahlia varieties.
These tubers will produce plants that are clones of the parent dahlia plant. Growing dahlias from seed on the other hand will produce new dahlia varieties.
Dividing dahlia tubers helps to reduce the size of the clump, making storage so much easier.
The division process allows you to cut away damaged and rotten tubers, which are quite common, to keep the healthy tubers in good shape.
When you open up a clump of tubers, you may also discover black spots in the crown that can be cut away, again preventing the spread of rot. Inspecting and discarding damaged or rotting tubers during division minimizes the risk of spreading disease to healthy plants.
Dividing prevents tubers from competing for nutrients, water, and space when they are replanted, which can stunt growth and reduce blooming potential. The process encourages healthy, vigorous growth and more blooms.
Step By Step Instructions
- Some gardeners divide their dahlia clumps in spring. Others prefer to divide in fall, which is my preference.
- Use clean, sharp tools for clean cuts.
- Rinse the dirt from the dahlia clump.
- Trim off the long roots attached to the tubers.
- Identify “eyes” on the crown (growth points for new plants). Sometimes these are not readily visible in fall.
- If the clump is very large it may be necessary to divide it right down the middle, so you will have better visibility and access to individual tubers.
- Separate tubers with at least one visible eye each. If you are not sure the tuber has an eye, you can save it anyway. Eyes will be more visible in spring.
- The top part of the tubers attached to the crown often resembles an inverted mushroom cap, so try to cut the tubers preserving some of this structure.
- Just make sure to get a piece of the crown at the top of each tuber.
- Discard damaged, rotting, or eyeless tubers.
- Remove any areas of potential rot (darkened areas) from the tuber in an effort to keep the tuber clean and healthy.
Storing Divided Tubers
Cure tubers further by letting them dry for a few days. This is important, to allow drying of the surface, and healing of any lesions from the cutting process.
Store in a container with peat moss or vermiculite. Some use wood shavings, although this option can tend to dry out the tubers.
Wrapping individual tubers in plastic wrap is also a way to store, preventing dehydration as well as spread of rot between tubers, by keeping them separated.
Plastic wrap is a less expensive method of storage, with good results. Just make sure that the tubers are completely dry before wrapping.
When storing, keep in a cool, frost-free location (40–50°F).
Label tubers with the cultivar name for easy identification.
Check on your dahlia tubers throughout the winter months, to ensure that they are tolerating the storage conditions. Remove any rotting tubers to help prevent spread to the others.
Properly stored tubers are protected from rot, frost, and pests during the winter, ensuring they survive until the next growing season.
Maintaining tubers in ideal conditions (cool, dark, and slightly humid) prevents drying out or mold development.
Replanting The Dahlia Tubers In Spring
In spring the dahlias will reawaken, and the eyes on the tubers will become more prominent. As the temperatures warm, the eyes will begin to sprout.
Divided tubers with a good “eye” (growth point) are more likely to produce stronger stems, lush foliage, and abundant, larger flowers. Younger, smaller tubers tend to be more productive than old, woody ones.
Tubers without eyes can be tossed.
Those with eyes and sprouts can be planted, after the last frost in your growing zone. Even if the sprouts accidentally break off, you can still plant them, because they will likely regrow.
Dahlia tubers will need at least 2.5 to 3 months of growth after planting, to produce blooms. Some larger dahlias will need even more time.
Frequently Asked Questions
1. Do I have to dig up my dahlias every year?
If you live in a region with freezing winters, you must dig up and store dahlia tubers to protect them from frost. In warmer climates, they can be left in the ground but may still benefit from periodic division.
2. How do I know if a tuber is viable for replanting?
A viable tuber should have a firm, plump texture and at least one visible “eye” (a small growth point near the crown). Tubers without eyes won’t sprout.
3. How do I find the “eyes” on a dahlia tuber?
Eyes are usually small, raised bumps near the crown where the stem connects to the tuber. They may be more visible after the tubers have been cured for a few days. They are also easier to see in spring when they begin to sprout.
4. How often should I divide my dahlia tubers?
Dividing every 1–2 years is ideal to prevent overcrowding and promote healthier plants and more abundant blooms. If the clump is large, tangled, or has many old, woody tubers, it’s time to divide to promote better growth and blooming.
5. What should I do if my tubers are shrivelled or soft?
Shrivelled tubers may still be viable, as long as they are still somewhat soft. Try to prevent further dehydration by wrapping in plastic wrap. Soft or mushy tubers should be discarded as they are likely rotting.
In Summary
Proper division and storage techniques will help to preserve the health of your dahlia collection for years to come. This ensures that your favorite varieties continue to thrive and produce blooms season after season.
Dividing and storing tubers also eliminates the need to repurchase dahlia plants annually, unless you are looking for new varieties, making it a budget-friendly practice for gardeners.
By digging, dividing and storing dahlia tubers correctly, you’re setting the stage for healthier, more robust plants, while also saving money and ensuring the longevity of your garden’s beauty.
Dividing also gives you the flexibility to replant dahlias in different areas of your garden, experimenting with new layouts or combinations.
Not to mention all the extra tubers that can result from just one planting, which you can share with other dahlia lovers! Happy digging!
Have you ever tried to dig and divide dahlia tubers at the end of the season? Be sure to leave a comment below to share your experience!
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