Table of Contents
- Introduction
- Understanding the Dahlia Lifecycle
- Waiting for the Right Time to Dig
- Preparing for the Harvest
- How to Dig Up Your Dahlia Tubers
- Cleaning and Curing Your Tubers
- Anatomy of a Dahlia Tuber
- To Divide or Not to Divide?
- Choosing Your Storage Medium
- Packing Your Tubers for the Winter
- Finding the Perfect Storage Spot
- The Monthly Winter Check-In
- Dealing with Common Challenges
- Preparing for Spring
- Encouraging a Successful Harvest
- Conclusion
- FAQ
Introduction
There is nothing quite like the sight of a dahlia garden in full bloom during late summer. The vibrant colors and intricate petal patterns bring so much joy to the yard, and it is natural to want to keep that beauty going year after year. While dahlias are tender perennials that cannot survive freezing ground temperatures, saving the tubers is a simple and rewarding process.
At Longfield Gardens, we want to help you enjoy your favorite varieties for many seasons to come. Saving your own tubers is a great way to grow your collection and ensure your most beloved blooms return to your garden. This guide will walk you through the process of digging, cleaning, and storing your dahlias so they stay healthy through the winter months.
With a little bit of care and the right timing, you can protect your investment and look forward to even bigger, more beautiful plants next spring. Learning how to save your tubers is a simple skill that makes gardening feel even more achievable and fun.
Understanding the Dahlia Lifecycle
[Scale?]Dahlias[/Scale?] grow from underground storage organs called tubers. If you want to keep the color going next season, browse our Red Collection. During the summer, the plant uses these tubers to store energy and produce those stunning flowers we all love. In warm climates, dahlias can stay in the ground all year. However, in most parts of the United States, the ground freezes in the winter, which would turn the watery tubers into mush.
To keep them safe, we lift them out of the soil and store them in a cool, frost-free place until spring. This process is often called overwintering. It allows the plant to go into a dormant state, which is essentially a deep sleep. While they are dormant, they don't need light or soil, just a stable environment that keeps them from drying out or freezing.
By saving your tubers, you are also giving yourself the chance to have more plants for free. As a dahlia grows through the summer, it naturally creates more tubers underground. When you dig them up in the fall, you will find that a single tuber has grown into a large clump. You can eventually divide these clumps to create multiple new plants.
Waiting for the Right Time to Dig
Timing is one of the most important parts of successfully saving your dahlias. If you're planning next year's display, take a look at the Purple Collection. If you dig them up too early, the tubers might not be fully mature. Mature tubers have tougher skin and more stored energy, which helps them survive the long winter months.
The best signal to start the process is the first frost of the season. You will notice your dahlia plants look a bit sad after a cold night. The leaves may turn black or brown and go limp. This is perfectly normal and is actually a helpful sign from nature. The cold tells the plant to stop sending energy to the leaves and start focusing all its resources on the tubers underground.
Many gardeners like to wait about a week after the first "killing frost" before they start digging. This short waiting period allows the tubers to "cure" slightly while still in the ground. If your area doesn't get a hard frost until very late in the year, you should aim to dig them up by mid-November. You want to get them out before the ground itself freezes solid, as that is when the tubers can be damaged.
Preparing for the Harvest
Before you head out with your shovel, it helps to do a little bit of prep work. First, make sure you have your labels ready. It is very easy to forget which tuber is which once the green foliage is gone. You can use waterproof tags, garden markers, or even write directly on the tuber with a soft pencil or felt-tip pen later.
You will also want to clean your tools. Using a simple solution of one part bleach to ten parts water to wipe down your shears or shovels is a great habit. This helps prevent the spread of any tiny garden pests or diseases from one plant to another.
Essential Tools for Saving Tubers
- A sturdy garden fork or spade
- Sharp bypass pruners or loppers
- A garden hose with a spray nozzle
- Mesh bags, cardboard boxes, or plastic bins
- Storage medium (like peat moss or wood shavings)
- Labels and a waterproof marker
How to Dig Up Your Dahlia Tubers
When it is time to dig, the goal is to be as gentle as possible. Dahlia tubers are connected to the main stem by a narrow "neck." This neck is quite fragile. If it snaps or gets a deep crack, the tuber may not be able to sprout again in the spring.
Start by cutting the main stalk of the dahlia plant down to about 4 to 6 inches above the ground. This "handle" gives you something to hold onto, but do not use it to pull the plant out of the earth. Instead, use your garden fork to loosen the soil in a wide circle around the plant.
Aim to place your fork about 12 inches away from the center of the stalk. This ensures you won't accidentally slice through the tubers. Gently lift the soil from all sides. Once the ground is loose, you can carefully lift the entire clump out of the hole.
Key Takeaway: Always dig wider than you think you need to. It is much better to lift a little extra soil than to accidentally damage a tuber with your shovel.
Cleaning and Curing Your Tubers
Once the clumps are out of the ground, shake off any large chunks of soil. Some gardeners prefer to wash their tubers immediately with a garden hose. This makes it much easier to see the eyes (the small bumps where next year’s growth will start) and to spot any signs of rot. If you have heavy clay soil, washing is usually the best way to get them clean.
If you have very sandy soil, you might find that you can simply let the soil dry and then brush it off with a soft brush. Whichever method you choose, the next step is curing. Curing is just a fancy word for letting the tubers dry out a bit so their skin toughens up. For a more detailed winter-storage walkthrough, see How to Keep Dahlia Bulbs Over the Winter.
Place your cleaned tubers in a cool, dry area that is protected from the sun and wind. A garage or a covered porch works well. Turn the clumps upside down so any water trapped in the hollow stems can drain out. Let them sit for 24 to 48 hours. You want the outside to feel dry to the touch, but you don't want the tubers to start shriveling or looking like raisins.
Anatomy of a Dahlia Tuber
To save your dahlias successfully, it helps to know what you are looking at. A viable dahlia tuber needs three specific parts to grow into a plant next year:
- The Body: This is the thick, fleshy part that stores the food.
- The Neck: This is the narrow part that connects the body to the crown.
- The Crown: This is the top part where the tuber meets the old stem.
The most important feature to look for is the "eye." The eye is a small, slightly raised bump found on the crown. This is the only place where a new sprout will grow. If a tuber breaks off without a piece of the crown and at least one eye, it will not grow, even if the body of the tuber looks healthy.
To Divide or Not to Divide?
One common question we hear at Longfield Gardens is whether you should divide the clumps in the fall or wait until the spring. Both methods work well, and the choice usually depends on how much storage space you have.
Dividing in the Fall
If you divide in the fall, you save a lot of space. Individual tubers are much smaller than a whole clump. It is also easier to cut the tubers while they are still somewhat soft. However, it can be harder to see the eyes in the fall because they are often dormant and very small.
Dividing in the Spring
Many gardeners prefer to store the entire clump and divide it in the spring. By spring, the eyes often start to swell or even sprout slightly, making them much easier to see. The downside is that you need more storage space, and the clumps can become quite hard and woody over the winter, making them a bit tougher to cut.
If you are a beginner, we often suggest storing the whole clump. It is a bit more forgiving, and you won't risk cutting off the eyes accidentally before you know exactly what they look like.
Choosing Your Storage Medium
Dahlias need a specific balance of moisture during the winter. If they stay too wet, they will rot. If they get too dry, they will shrivel up and die. To help maintain this balance, we pack them in a "storage medium." This material acts like a blanket, insulating them and regulating moisture.
There are several great options for storage:
- Peat Moss: This is a classic choice because it holds onto just enough moisture without being "wet."
- Vermiculite: A mineral that is excellent for moisture control. It is very clean and easy to work with.
- Coarse Wood Shavings: Often sold as pet bedding (look for pine or cedar), these allow for good airflow.
- Pet Litter (Paper-based): Unscented, recycled paper pellets can also work well to keep things dry but stable.
Avoid using standard potting soil, as it often contains too much moisture and can lead to rot. Also, avoid using plastic bags that are sealed tight. Tubers are living things and need a tiny bit of air to breathe.
Packing Your Tubers for the Winter
Once your tubers are cured and your storage medium is ready, it is time to pack them away. Use a sturdy container like a cardboard box, a plastic bin with the lid left slightly cracked, or even a heavy-duty paper bag.
- Place a 2-to-3-inch layer of your chosen medium in the bottom of the container.
- Lay your tubers or clumps on top of the layer. Make sure they aren't crowded or touching each other if possible.
- Cover the tubers completely with more of the medium.
- If you have a lot of tubers, you can do multiple layers, just make sure there is plenty of packing material between them.
- Don't forget to include your labels! You can tuck the tag right into the box or tie it to the stem "handle."
If you are storing individual tubers that you have already divided, some gardeners like to wrap each one loosely in a piece of newspaper or plastic wrap before placing it in the box. This provides an extra layer of protection against rot spreading from one tuber to another.
Finding the Perfect Storage Spot
The environment where you keep your boxes is just as important as how you pack them. You are looking for a spot that is "cool, dark, and dry." The ideal temperature range is between 40°F and 45°F.
If the temperature stays above 50°F, the tubers might think it is springtime and start to sprout too early. If the temperature drops below 35°F, you run the risk of them freezing.
Good storage locations include:
- An unheated (but attached) garage
- A cool basement or cellar
- A crawl space
- An insulated garden shed
Keep the boxes up off the floor if the floor is concrete, as concrete can pull moisture out of the boxes or get very cold. Placing them on a shelf or a wooden pallet is a simple way to keep them safe. If you are not sure which zone you garden in, check the Hardiness Zone Map.
The Monthly Winter Check-In
Saving tubers isn't a "set it and forget it" task. It is a good idea to check on your dahlias once a month during the winter. This only takes a few minutes and can save your whole collection.
Open your boxes and feel a few of the tubers. If they feel firm like a fresh potato, they are doing great. If they feel a little bit soft or look shriveled, they might be too dry. You can give the storage medium a very light misting of water with a spray bottle to add a touch of humidity. For a more detailed winter-storage walkthrough, see How to Keep Dahlia Bulbs Over the Winter.
On the other hand, if you see any fuzzy mold or if a tuber feels mushy, that is a sign of rot. Remove any damaged tubers immediately so the rot doesn't spread to their neighbors. If the packing material feels damp, leave the lid off the box for a day or two to let some of the moisture evaporate.
What to do next:
- Mark your calendar for a "Dahlia Check-up" on the first weekend of every month.
- Keep a spray bottle of water nearby for quick moisture adjustments.
- Have an extra bag of dry peat moss or shavings ready in case you need to replace damp material.
Dealing with Common Challenges
While the process is straightforward, nature can sometimes throw a curveball. The most common issue gardeners face is rot. This usually happens if the tubers were put away while they were still wet or if the storage area is too humid. By checking them monthly, you catch this early.
Another challenge is "mother roots." When you dig up a clump, you will often see one tuber that looks much older, darker, and more wrinkled than the others. This is the original tuber you planted in the spring. While you can save it, many gardeners find that the "mother root" is more prone to rot over the winter. It often produces weaker plants the following year. If you have plenty of healthy new tubers in the clump, it is usually best to discard the mother root and focus on the fresh growth.
If you find that your storage area is consistently too cold, you can wrap your boxes in an old moving blanket or some burlap for extra insulation. Small adjustments like these make the process much more successful and less stressful. If you want extra peace of mind when shopping for new tubers, our guarantee helps protect your investment.
Preparing for Spring
As the days get longer and the weather begins to warm, your dahlias will start to "wake up." You might notice the eyes on the crowns starting to swell or turn a light green or pink color. This usually happens in late March or April. For a planting refresher, see How to Plant and Grow Dahlia Tubers.
When you see these signs of life, it is an exciting moment! It means your tubers have successfully survived the winter. You can take them out of their storage boxes and start thinking about your garden layout. If you haven't divided your clumps yet, this is the perfect time to do it. If you need help checking your zone before planting, the Hardiness Zone Map is a great place to start.
Wait to plant them back in the ground until the soil has warmed up to about 60°F and all danger of frost has passed. Planting too early in cold, wet spring soil can cause the tubers to rot before they have a chance to grow. A little bit of patience in the spring goes a long way toward a summer full of blooms.
Encouraging a Successful Harvest
Every garden is a little bit different. Your soil, your local weather, and even the specific variety of dahlia you grow will all affect how well your tubers store. Don't be discouraged if you lose a few tubers during your first winter. It is all part of the learning process.
The more you practice, the more you will get a "feel" for the right moisture levels and the best storage spots in your home. Some gardeners even try two different storage methods—like half in peat moss and half in wood shavings—to see which one works better for their specific environment. This experimental approach is a fun way to become a more confident gardener.
Remember that gardening is meant to be a rewarding activity. The time you spend saving your tubers in the fall is an investment in your future garden, and our guarantee is there to give you extra confidence. There is a special kind of satisfaction that comes from planting a tuber you saved yourself and watching it grow into a spectacular flower a few months later.
Conclusion
Saving your dahlia tubers is a simple, effective way to keep your garden beautiful year after year. By following these steps—waiting for the frost, digging carefully, curing properly, and storing in a cool, stable environment—you can enjoy your favorite varieties for many seasons. It is a practical way to expand your flower beds and share your favorite varieties with friends and neighbors. For a ready-made next step, explore the Sunlit Jewel Collection.
At Longfield Gardens, we believe that every gardener can find success with dahlias. Whether you are growing a few in pots or have a whole field of blooms, the process of overwintering is a great skill to have in your gardening toolkit.
- Wait for the first killing frost to signal harvest time.
- Dig carefully with a fork to protect the fragile tuber necks.
- Cure tubers for 24-48 hours before packing them away.
- Store at 40-45°F in a moisture-balancing medium like peat moss.
- Check your tubers once a month to ensure they stay firm and healthy.
Keeping your tubers safe through the winter is the first step toward a spectacular summer garden. With a little care now, you’ll be rewarded with a season of breathtaking blooms.
We look forward to seeing your garden grow and thrive! For more tips on plant care and planning your dream garden, explore our Learn page for more guides and variety spotlights.
FAQ
How do I know if a dahlia tuber is dead?
A healthy tuber should feel firm, similar to a fresh potato or a carrot. If a tuber is mushy, slimy, or smells unpleasant, it has likely rotted and should be thrown away. If a tuber is extremely shriveled, brittle, and lightweight, it has dried out too much and is unlikely to sprout.
Can I store dahlias in the refrigerator?
While a refrigerator is cool, it is generally not the best place for dahlia tubers. Most refrigerators are kept around 35-38°F, which is a bit too cold, and the air inside is often very dry. Additionally, some fruits and vegetables release gases that can harm the tubers. A cool basement or garage is usually a much better choice. For shipping timing and zone-based delivery details, see our Shipping Information.
Do I have to wash the dirt off before storing?
It isn't strictly required, but washing makes it much easier to inspect the tubers for damage, pests, or rot. If you have light, sandy soil, you can often get away with just brushing them off. If you have heavy clay, washing is recommended to prevent soil-borne diseases from being trapped against the tuber skin during storage.
What happens if I don't wait for a frost to dig them up?
You can dig up dahlias before the frost if you need to, but the tubers may not be as hardy. The frost signals the plant to go dormant and toughens the skin of the tubers, which helps them last through the winter. If you must dig early, try to wait until at least mid-autumn so the tubers have had maximum time to grow and store energy.