Introduction
There is nothing quite like the late-summer glory of a dahlia garden. These dahlias are the stars of the season, producing a breathtaking range of colors and shapes that keep our vases full until the first frost. When the weather begins to turn cool, the focus shifts from enjoying the blooms to preserving the "bulbs"—which are technically called tubers—for the next year.
At Longfield Gardens, we want to help you enjoy this rewarding cycle of growth year after year. Removing dahlia tubers from the ground is a simple process that anyone can master with a bit of patience and the right technique. By lifting them safely, you protect your investment and ensure that your favorite varieties return even stronger next spring.
This guide is designed for gardeners who want a clear, stress-free path to harvesting their dahlias. We will cover when to start, what tools you need, and exactly how to lift and store dahlia bulbs without causing damage. Following these steps will help you transition your garden into its winter rest with confidence.
Understanding Why We Remove Dahlia Tubers
Dahlias are native to the warm mountain regions of Mexico. Because of these tropical roots, they are not naturally equipped to survive freezing temperatures. In most parts of the United States, leaving the tubers in the ground over winter would lead to them freezing, turning to mush, and eventually rotting.
Removing them from the soil allows you to control their environment during the cold months. This "lifting" process is essential for anyone living in USDA hardiness zones 7 or colder. While some gardeners in very warm climates can leave them in the ground with heavy mulch, most of us find that lifting them is the only way to guarantee they survive.
Beyond survival, removing the tubers gives you a chance to inspect the health of your plants. You can see how much the root system has grown and ensure there are no signs of disease or pests. It is also the first step in multiplying your collection, as one tuber planted in the spring often turns into a large clump by the fall.
Timing the Harvest Correctly
One of the most important rules of removing dahlia tubers is to wait for the right signal from nature. We recommend waiting until a killing frost has hit your garden. You will know this has happened when the lush green foliage turns black or dark brown overnight.
This frost signals to the plant that it is time to go dormant. When the top of the plant dies, the energy from the leaves and stems moves down into the tubers. This "curing" process in the soil helps the tubers toughen up, which makes them much more likely to survive the winter storage period.
If you live in an area where frost comes very late, you should still aim to remove the tubers by mid-November. The goal is to get them out before the ground itself freezes solid. A light frost that only nips the flowers is usually not enough; you want to see the main foliage blackened before you begin the removal process.
Key Takeaway: Wait at least a few days to a week after the first killing frost before digging. This short waiting period allows the tubers to "set their eyes" and develop a thicker skin for storage.
Essential Tools for Removing Dahlia Bulbs
Having the right tools makes the job much easier and reduces the risk of accidentally slicing through a prize tuber. You do not need expensive equipment, but a few specific items are very helpful.
- Garden Fork (Pitchfork): This is the single most important tool. Unlike a solid shovel, a fork is less likely to cut through a tuber if you accidentally strike the clump. The tines allow soil to fall through while you lift.
- Loppers or Heavy Pruners: You will need these to cut through the thick, woody stems of the dahlia plants.
- Garden Hose with a Spray Nozzle: If you have heavy soil, a gentle stream of water helps remove dirt so you can see what you are doing.
- Plant Tags and Waterproof Markers: You must label your tubers as soon as they come out of the ground. It is nearly impossible to tell varieties apart once the flowers are gone.
- A Wheelbarrow or Garden Crate: This helps you move the heavy clumps from the garden bed to a cleaning area without dropping and breaking them.
Preparing the Plants for Removal
Before you reach for your garden fork, you need to clear away the top growth. This makes the workspace much cleaner and gives you a clear view of where the center of the plant is located.
Start by using your loppers to cut the dahlia stems down to about 4 to 6 inches above the soil line. Do not cut them flush with the ground. Leaving a short "handle" of the stem is very useful. It marks the center of the tuber clump and gives you something to hold onto while you are prying the clump out of the soil.
Once the stalks are cut, clear away the foliage and move it to your compost pile (as long as the plants were healthy). This is also the best time to double-check your labels. If the original tag is still on the stake, move it to the stem handle or tie it loosely around the base so the name stays with the correct tubers.
What to Do Next: Preparation Checklist
- Check the weather forecast for a dry, clear day to make digging easier.
- Cut stems to 6 inches high using sharp, clean loppers.
- Clear away dead foliage to prevent tripping hazards.
- Ensure your labeling materials are ready and nearby.
The Step-by-Step Digging Process
This is the part where patience pays off. Dahlia tubers grow outward from the center stem, often much further than you might expect. If you dig too close to the stem, you will slice through the tubers, which can lead to rot during storage.
Step 1: Dig a Wide Circle
Start by placing your garden fork in the soil about 12 inches away from the main stem. Push the fork straight down into the earth. Do this in a circle all the way around the plant. This "pre-digging" loosens the outer roots and ensures you aren't cutting into the main tuber clump.
Step 2: Pry Gently
After you have loosened the soil in a circle, tilt the handle of the fork back toward you to pry the soil upward. Work your way around the plant again, prying gently from different angles. You want the entire clump of soil and tubers to lift as one unit.
Step 3: Use the Stem Handle
Once the clump feels loose, place one hand on the "stem handle" you left earlier and use the other hand to lift from underneath with the fork. Gently pull the clump out of the hole. If you feel significant resistance, stop pulling and use the fork to loosen the soil a bit more. Never yank on the stem, as the "necks" where the tubers attach to the crown are very fragile and can snap easily.
Step 4: Initial Soil Removal
Hold the clump by the stem and give it a very gentle shake to remove large clods of dirt. If the soil is dry and sandy, most of it will fall away easily. If you have heavy clay soil, the dirt might cling tightly. In this case, use your fingers or a small wooden stick to poke away the largest chunks of mud.
Cleaning and Rinsing the Tubers
Once the tubers are out of the ground, they need to be cleaned. Soil contains microorganisms and moisture that can cause rot over the winter, so getting them relatively clean is a good practice.
Many gardeners prefer to use a garden hose to rinse the tubers. Use a gentle spray to wash away the remaining soil. Be careful not to use high-pressure settings, as this can tear the skin of the tubers. As you wash them, you will start to see the individual tubers and the "crown," which is the area where the tubers meet the stem.
If your garden is very large or your water is already turned off for the season, you can also let the clumps dry for a few hours in the sun (if it isn't freezing) and then brush the dry soil off with a soft brush. At Longfield Gardens, we find that a quick rinse is often the most efficient way to see the condition of the tubers and look for any "eyes"—the small buds that will become next year's stems.
The Curing Phase
You cannot put fresh, wet tubers directly into a storage box. They need a short period to "cure" or dry out. This helps the skin toughen up and allows any small nicks or cuts from the digging process to heal over.
Place your cleaned tuber clumps in a frost-free area with good air circulation. A garage, basement, or sturdy shed works well. Some gardeners like to turn the clumps upside down so that any water trapped in the hollow stems can drain out. This prevents "crown rot," which is a common issue when moisture sits at the top of the tubers.
Let the tubers dry for 1 to 3 days. They should feel dry to the touch, and the skin might look slightly dusty or wrinkled. You do not want them to stay out so long that they become shriveled and hard like a piece of wood. The goal is simply to remove surface moisture and dry out the cut ends of the stems.
Key Takeaway: Proper curing is a "middle ground" step. Dry the tubers enough to prevent mold, but not so much that they lose their internal moisture reserves.
Organizing and Labeling
Before you move your tubers into their final winter home, you must ensure they are properly labeled. It is one of the most common gardening mistakes to think you will remember which tuber is which. By spring, every tuber clump looks identical.
There are several easy ways to label:
- Dahlia Pens: You can buy special garden markers or use a soft pencil to write the variety name directly on the skin of a large tuber.
- Tagging: Use plastic or metal tags tied loosely around the stem handle with twine.
- Mesh Bags: Place individual clumps in mesh bags with a label tucked inside.
If you are dealing with many different varieties, keep them separated during the cleaning and curing process. Work with one variety at a time to ensure no tags get mixed up. Consistent labeling is the difference between a planned garden design and a surprise mix next year.
Managing Realistic Expectations
When you remove dahlia tubers, you will notice that every plant is different. This is a normal part of gardening. Some varieties are "productive," meaning they create a massive clump of 15 or 20 tubers. Others are "shy" and may only produce two or three small tubers.
The size of the tuber also varies. A dinnerplate dahlia might produce tubers the size of large potatoes.
A smaller pompon variety might produce tubers that look like thin fingerling potatoes. Both are perfectly healthy and capable of growing a full-sized plant next year.
You may also find that the original tuber you planted in the spring—often called the "mother root"—looks dark, wrinkled, or even a bit soft. This is normal. The plant used the energy from that root to grow. While the mother root often rots away, the new tubers surrounding it are what you need for next season. If a tuber feels completely hollow or squishy like a sponge, it is best to remove it and focus on the firm, healthy ones.
Preparing for Storage
While the primary goal of this guide is the removal process, a brief note on storage will help finish the job. Once your tubers are removed, cleaned, and cured, they need a cool, dark place to rest.
Most gardeners store their dahlias in a medium that helps regulate moisture. Popular choices include:
- Untreated Wood Shavings: Excellent for airflow.
- Peat Moss: Holds a bit more moisture but is very clean.
- Vermiculite: Great for preventing rot.
Place a layer of your chosen medium in a cardboard box or a plastic bin with some air holes. Lay the tubers inside so they are not touching each other, then cover them with more of the medium. Store the boxes in a location that stays between 40°F and 50°F. If the temperature drops below freezing, the tubers will die. If it gets too warm, they may begin to sprout too early or shrivel up.
Conclusion
Removing dahlia bulbs is a satisfying end-of-season ritual that bridges the gap between the colors of autumn and the promise of spring. By taking the time to lift them gently and clean them properly, you are preserving a piece of your garden's history. This simple act of care ensures that your yard will be filled with spectacular blooms once the warm weather returns.
- Wait for the first killing frost to signal the plant to go dormant.
- Use a garden fork to dig a wide circle and pry the clump upward.
- Never pull or yank on the stem, as the necks of the tubers are fragile.
- Cure the tubers in a cool, dry place for a few days before packing them away.
When you start with plants backed by our 100% Quality Guarantee, you are setting yourself up for success from the very beginning. We take pride in providing healthy, true-to-variety tubers that are ready to perform in your garden. For more tips on garden care and planning your next colorful display, you can find helpful advice on our Garden Basics page.
"The secret to a beautiful dahlia garden next year is the care you give your tubers today. A little patience in the fall leads to an abundance of blooms in the summer."
We look forward to seeing your garden grow!
FAQ
How deep do I need to dig to remove dahlia tubers?
Dahlia tubers are usually found in the top 6 to 12 inches of soil. When removing them, push your garden fork all the way down into the soil to ensure you are getting underneath the entire clump. If you feel the fork hitting something solid, move a few inches further out and try again to avoid piercing the tubers.
What should I do if I accidentally break a tuber off the clump?
If a tuber breaks off, check to see if it has a piece of the "crown" (the area where it was attached to the stem) still attached. If it has a piece of the crown and a visible "eye" or bud, it may still grow. If it snaps off in the middle of the tuber, it will likely not grow a new plant, but you can still compost it.
Do I have to wash the tubers, or can I just shake off the dirt?
You do not strictly have to wash them, especially if you have sandy soil that falls away easily. However, washing makes it much easier to see the health of the tubers and find the eyes. If your soil is heavy clay, washing is highly recommended because clay holds a lot of moisture that can cause rot in storage.
Can I remove my dahlia tubers before the frost if I have to travel?
Yes, you can remove them earlier if necessary. If you must dig them before a frost, the tubers may be slightly less mature and have thinner skin. To help them prepare, you can cut the stems back and wait a few days before digging, which encourages the plant to start its dormancy even without a frost.
