Introduction
There is nothing quite like the late-summer glory of a dahlia garden. These spectacular plants are the undisputed champions of the autumn landscape, offering a breathtaking variety of colors, shapes, and sizes. Whether you are growing massive dinnerplate varieties or charming pompons, the joy of seeing those first buds open is a highlight of the gardening year. At Longfield Gardens, we want to help you preserve that beauty so you can enjoy your favorite varieties season after season.
Learning how to pull dahlia tubers is one of the most rewarding skills a gardener can master, especially if you grow pompons. While these tropical beauties are tender, they are also incredibly generous, often multiplying their numbers beneath the soil while you are busy enjoying their blooms. By taking a little time to lift and store them correctly, you can turn a single plant into a stunning collection over just a few years.
This guide will walk you through the simple, effective steps to safely harvest your dahlia tubers. We will cover the best timing for digging, the tools you need, and the techniques that keep your tubers healthy and ready for spring. With the right approach, winter storage becomes a straightforward part of your garden's natural rhythm.
Understanding the Dahlia Life Cycle
Dahlias are native to the warm mountain regions of Mexico and Central America. In those climates, they grow as perennials, staying in the ground year-round. However, for most gardeners in the United States, the cold winter temperatures present a challenge. If you need a quick reference, see our Hardiness Zone Map.
The tubers themselves are essentially storage tanks. Throughout the summer, the plant uses its foliage to gather energy from the sun and store it in these underground structures. By the end of the season, a healthy dahlia plant has created a cluster of tubers that look a bit like a bunch of narrow sweet potatoes. Each of these tubers contains the energy and nutrients needed to kickstart growth the following spring.
The goal of pulling your dahlias is to move these storage tanks into a dormant state in a protected environment. Think of it as putting your plants to bed for a long, cozy winter nap. When the soil warms up again in May or June, you will be ready to wake them up and start the cycle over.
When Is the Best Time to Pull Dahlia Tubers?
Timing is one of the most important factors when learning how to pull dahlia tubers. You want to give the plant as much time as possible to mature its tubers, but you must get them out of the ground before the winter weather becomes too severe.
The Magic of the First Frost
For most gardeners, the "killing frost" is the ultimate signal. This occurs when temperatures drop low enough to turn the dahlia’s lush green foliage into a dark, mushy brown. While it might look a little sad at first, this is actually a helpful part of the process. This frost tells the plant that its growing season is officially over.
Once the foliage has been hit by frost, the plant begins to shift its remaining energy downward into the tubers. Many experienced growers prefer to wait about a week or two after this first frost before they start digging. This short waiting period allows the tubers to "cure" slightly while still in the ground. During this time, the "eyes" (the small bumps where next year's sprouts will emerge) often become more visible, and the skin of the tuber begins to toughen up for storage.
The 120-Day Rule
If you live in a region where a killing frost doesn't arrive until very late in the year, you can use the calendar instead. Most dahlias need at least 120 to 150 days of growth to produce mature, viable tubers. For a closer look at healthy tubers and their structure, read Dahlia Tubers: What You Need to Know.
Regardless of frost, you must pull your tubers before the ground itself freezes. While the tubers can handle a light frost on the leaves, they will turn to mush if the soil around them reaches freezing temperatures. If you see a week of deep, sustained freezes in the forecast, it is time to get outside and start digging.
Gathering the Right Tools
Having the right tools on hand makes the process of pulling dahlia tubers much easier and prevents accidental damage to the delicate roots. You do not need professional-grade machinery, but a few specific items will help you work more efficiently.
- Lopers or Heavy-Duty Pruners: You will need these to cut through the thick, woody stems of mature dahlia plants.
- Garden Fork: This is the most important tool for the job. A sturdy garden fork (sometimes called a pitchfork) is much better than a shovel. The tines of the fork allow you to loosen the soil without the risk of slicing through the tubers, which a flat shovel blade might do.
- Garden Hose: A gentle stream of water is the best way to clean the soil off the tubers once they are out of the ground.
- Labels and Waterproof Markers: It is surprisingly easy to forget which tuber is which once the flowers are gone. Use plastic tags or even write directly on the tuber skin with a soft-lead pencil or waterproof marker.
- Storage Containers: Cardboard boxes, paper bags, or plastic bins with holes for ventilation are all excellent choices for the next stage.
How to Pull Dahlia Tubers Step-by-Step
Once the timing is right and your tools are ready, you can begin the harvesting process. Follow these steps to ensure you lift the tubers safely and maintain their quality.
Step 1: Cutting Back the Foliage
The first step is to remove the top growth. Use your pruners or lopers to cut the main stem of the dahlia, leaving about 4 to 6 inches of the stem sticking out of the ground. This remaining piece of stem acts as a "handle" that helps you locate the center of the tuber clump.
Be careful as you do this, as dahlia stems are hollow. In rainy weather, these hollow stems can collect water, which can lead to rot if left too long. If you aren't digging immediately, some gardeners choose to cover the cut stems with a bit of aluminum foil or flip a small nursery pot over them to keep them dry.
Step 2: Loosening the Soil
This is where your garden fork comes into play. It is vital to remember that dahlia tubers grow outward from the center stem, often much further than you might expect. To avoid stabbing the tubers, start your digging at least 12 inches away from the main stem on all sides.
Insert the fork vertically into the soil and gently rock it back and forth to loosen the earth. Work your way in a circle all the way around the plant. You want to feel the entire "root ball" start to lift and move as one unit. If you feel resistance, move your fork a few inches further out and try again.
Step 3: Lifting the Clump
Once the soil is thoroughly loosened, slide your fork deep under the clump. Place one hand on the "stem handle" for stability and use the fork to pry the clump upward. Avoid the temptation to yank the plant out by the stem alone. The "neck" of the tuber—the narrow part where it attaches to the main stem—is very fragile. If you pull too hard, the tubers can snap off, which often makes them unusable.
Instead, let the fork do the heavy lifting. As the clump clears the ground, support it from underneath with your hands. Gently shake the clump to remove large chunks of loose soil.
Step 4: Initial Cleaning and Inspection
Once the tuber clump is out of the ground, move it to a clear area of the garden or a lawn. Use your garden hose with a gentle spray setting to wash away the remaining dirt. Getting the tubers clean now makes it much easier to see what you are working with and helps prevent soil-borne diseases from following the plants into storage.
As you wash them, take a close look at the clump. You are looking for firm, plump tubers that are securely attached to the main stem. It is normal for some of the smaller, thread-like roots to break off, and you can trim those away with your pruners.
Key Takeaway: The "One Foot" Rule Always start digging at least 12 inches away from the center stem. Dahlia tubers grow horizontally, and keeping your distance ensures you won't accidentally spear the very tubers you are trying to save.
Understanding Tuber Anatomy
Before you move on to storage, it helps to understand what makes a tuber viable. For a closer look, read Dahlia Tubers: What You Need to Know.
Not every part of the root system will grow into a new plant. To be successful next year, a dahlia tuber needs three specific parts:
- The Body: This is the fat, starchy part that holds the energy.
- The Neck: This is the thin "bridge" between the body and the stem.
- The Crown (with an Eye): This is the most critical part. The "eye" is a small growth point located on the crown (the area where the neck meets the old stem).
If a tuber breaks off and loses its neck or crown, it will not grow a new plant. When you are pulling your dahlias, your primary goal is to keep that neck-to-crown connection intact.
Preparing Tubers for Winter Storage
After you have successfully pulled your dahlia tubers and washed them clean, they need a short period of preparation before they go into their winter containers. For the full planting-and-lifting walkthrough, see How to Grow Dahlias from Tubers.
Curing the Tubers
Curing is simply a fancy word for letting the tubers dry out slightly. Freshly dug tubers are very high in moisture. If you pack them away immediately while they are still wet, they are likely to rot.
Find a cool, dry place out of direct sunlight—a garage, a shed, or a covered porch works perfectly. Lay the tubers out on a tray, a piece of cardboard, or a mesh screen. Do not place them directly on concrete, as concrete can actually pull too much moisture out of the tubers and cause them to shrivel.
Let them dry for 2 to 3 days. You want the skin to feel dry to the touch and the leftover bits of soil to be easy to brush off. If the weather is particularly damp, you might need an extra day or two.
Trimming and Labeling
Once they are dry, you can do some final grooming. Use clean, sharp pruners to trim the main stem handle down to about 1 inch. You should also trim off any broken or damaged tubers and the long, "hairy" feeder roots.
Labeling is your best friend. We recommend using a soft pencil or a garden marker to write the variety name directly on the skin of the tuber. You can also tie a plastic tag around the neck. Trust us—by March, all dahlia tubers look exactly the same!
To Divide or Not to Divide?
One common question gardeners ask after learning how to pull dahlia tubers is whether they should divide the clumps right away or wait until spring. Both methods work, and the choice often depends on your available storage space.
Storing Whole Clumps
Storing the entire clump as it came out of the ground is the easiest method for beginners. Because the tubers stay attached to each other, they are less likely to dry out completely over the winter. This method also saves you a lot of time in the fall when garden chores are piling up.
The downside is that whole clumps take up a significant amount of space. You will need larger boxes and more packing material to keep them protected.
Dividing in the Fall
Many experienced gardeners prefer to divide their clumps into individual tubers before storing them. This is a great way to multiply your stock. Each individual tuber that has a piece of the crown and a visible eye can become a brand-new plant next year.
Dividing in the fall is often easier because the tubers are still relatively soft and easy to cut. However, it can be harder to see the "eyes" immediately after digging. If you aren't sure where the eyes are, it is perfectly fine to wait.
Successful Winter Storage Conditions
Now that your tubers are pulled, cleaned, and cured, they need the right environment to survive the winter. Think of their storage space like a root cellar.
The Temperature Sweet Spot
The ideal temperature for dahlia storage is between 40°F and 45°F. This is cold enough to keep the tubers dormant so they don't start growing too early, but warm enough that they won't freeze. An unheated basement, a crawl space, or an insulated garage are usually the best spots.
If the temperature drops below 35°F, the tubers are at risk. If it rises above 50°F, they may start to sprout or shrivel from the heat.
Choosing a Storage Medium
You don't want to leave your tubers sitting out in the open air all winter, or they will turn into wrinkled, dry husks. You need a packing material that helps regulate moisture. Popular choices include:
- Coarse Vermiculite: This is many gardeners' favorite choice because it holds just enough moisture without being "wet."
- Peat Moss: A classic option that is easy to find.
- Wood Shavings: The kind used for animal bedding works well and is very affordable.
- Newspaper: You can wrap individual tubers in several layers of dry newspaper.
Place a layer of your chosen medium in the bottom of a box, lay your tubers inside so they aren't touching each other, and then cover them with more material.
What to Do Next: Your Storage Checklist
- Check the temperature of your storage spot with a basic thermometer.
- Pack tubers in layers, ensuring none of them are touching.
- Keep the lid of your container slightly ajar to allow for minimal air circulation.
- Mark your calendar to check on them once a month.
Managing Moisture Throughout the Winter
While your dahlias are in storage, they are in a state of "suspended animation," but they are still living things. They need a tiny bit of moisture to stay plump, but too much moisture will cause them to rot.
Every 4 to 6 weeks, peek into your storage boxes. If a tuber feels light and looks shrivelled, it is getting too dry. You can give the packing material a very light misting with a spray bottle of water.
On the flip side, if you see any signs of mold or soft, mushy spots, the environment is too damp. Remove any rotting tubers immediately so the rot doesn't spread to the healthy ones. Increasing the airflow by opening the box lid a bit more can help solve this.
Troubleshooting Common Issues
Even when you follow the best practices for how to pull dahlia tubers, you might run into a few surprises. For season-long care tips, see 8 Tips for Growing Better Dahlias.
"I accidentally sliced a tuber with my fork!" Don't worry! This happens to the best of us. If the cut is clean, you can often save the tuber. Simply let it air dry for an extra day until the cut area "calluses" over (becomes dry and corky). If it is a clean break, the tuber should store just fine.
"My tubers look small compared to the ones I bought." Tuber size varies wildly between varieties. Some dahlias naturally produce "clumps" of small, finger-sized tubers, while others produce massive, potato-like roots. As long as the tuber is firm and has a piece of the crown attached, it has enough energy to grow.
"I can't see any eyes on my tubers." This is very common in the fall. The eyes are often tiny and dormant. If you aren't sure, just store the whole clump. In the spring, as the weather warms, those eyes will swell and turn pink or purple, making them much easier to identify.
The Reward for Your Hard Work
It might seem like a lot of steps at first, but once you have pulled your first few plants, you will realize how intuitive the process is. There is a deep sense of satisfaction that comes from tucked-away tubers, knowing that you have preserved a piece of your summer garden for next year.
Pulling dahlia tubers is an act of optimism. It is a way of looking forward to the next season while the current one fades. By giving your plants this little bit of extra care, you are ensuring that your garden will be even more spectacular next year—a stunning collection in the making.
At Longfield Gardens, we believe that every gardener can be successful with dahlias, and our 100% Quality Guarantee reflects that.
Conclusion
Successfully pulling dahlia tubers is a simple way to protect your investment and expand your garden for free. By waiting for the right timing, using a gentle hand with your garden fork, and providing a cool, dry winter home, you are setting the stage for a magnificent display next summer. Remember that gardening is a journey of learning, and every tuber you save is a victory.
- Wait for the first frost or mid-November to start digging.
- Dig wide to protect the fragile necks and crowns.
- Cure and dry your tubers for a few days before packing them away.
- Store them in a cool, dark place between 40°F and 45°F.
The next step is easy—just keep your tubers in their winter home until the spring sun warms the soil again. If you're planning ahead for next spring, see our Shipping Information. We look forward to seeing your garden in full bloom once more!
FAQ
How deep should I dig when pulling dahlia tubers?
Dahlia tubers usually grow in the top 6 to 12 inches of soil, but they can occasionally go deeper. It is best to push your garden fork in as deep as it will go—usually about 10 to 12 inches—to ensure you can get underneath the entire clump and lift it without snapping the roots.
Do I have to wash the tubers before storing them?
While some gardeners store their tubers with a bit of soil still attached, we recommend washing them. Cleaning the tubers makes it much easier to spot rot, find the eyes, and identify any pests. It also prevents soil-borne fungi from growing in your storage containers over the winter.
What happens if I don't pull my dahlia tubers?
In USDA zones 7 and colder, dahlia bulbs left in the ground will almost certainly freeze and rot as the soil temperature drops. In warmer zones (8 through 11), you may be able to leave them in the ground if the soil is well-draining, but even then, many gardeners pull them to divide the clumps and prevent overcrowding.
Can I store dahlia tubers in the refrigerator?
A refrigerator is generally too cold and too dry for long-term dahlia storage. Most fridges are set below 40°F, which can damage the tubers over several months. Additionally, the low humidity in a refrigerator can cause tubers to shrivel quickly. A cool basement or garage is a much safer bet.
