Table of Contents
- Introduction
- Knowing When to Dig Your Tubers
- Preparing the Plants for Lifting
- The Art of Digging Without Damage
- Cleaning and Inspecting Your Harvest
- The Importance of Curing
- To Divide or Not to Divide?
- Choosing the Right Storage Medium
- Finding the Perfect Storage Location
- Winter Check-ups and Troubleshooting
- Preparing for Spring Replanting
- Summary of the Storage Process
- FAQ
Introduction
Growing dahlias is one of the most rewarding experiences a gardener can have. There is a unique sense of pride that comes from seeing those first dinnerplate dahlias open in mid-summer. These plants provide a non-stop supply of color and texture until the very end of the growing season. Because they are so beautiful, many gardeners want to save their favorite varieties to plant again next year.
At Longfield Gardens, we want to help you enjoy these stunning flowers year after year. Dahlias are native to the warm climates of Mexico and Central America, which means they are not naturally equipped to survive freezing northern winters. Learning how to store dahlia tubers over winter is a simple skill that protects your investment and ensures a head start on next year’s garden. This process is straightforward and fits easily into your autumn garden cleanup routine.
This guide will walk you through the entire process of lifting, cleaning, and storing your tubers. We will cover the best timing for digging and how to create the perfect environment for their winter nap. Whether you are a beginner or an experienced grower, these steps will help you keep your tubers healthy and ready for spring. Storing your dahlias is an easy win that makes gardening more sustainable and enjoyable.
Knowing When to Dig Your Tubers
Timing is the first step toward successful winter storage. While it may be tempting to dig up your dahlias as soon as the weather turns chilly, waiting for the right moment helps the tubers mature. This extra time in the ground allows the plant to store energy and toughen its skin for storage.
In most parts of the United States, the signal to start digging is the first killing frost. This is the frost that turns the green foliage of your dahlias to black or dark brown. While the top of the plant looks finished, the tubers underground are perfectly safe for a short time. This sudden change in the plant actually signals the tubers to go into deep dormancy.
If you live in a region where frost comes very late, you can still dig your tubers in mid-November. The goal is to get them out of the ground before the soil itself freezes solid. A light frost is a helpful guide, but the calendar can also be your friend if the weather stays unusually warm.
Key Takeaway: Wait for a killing frost to turn the foliage brown before you begin digging. This natural cycle helps the tubers prepare for a long, healthy rest.
Preparing the Plants for Lifting
Once the foliage has turned brown, it is time to prepare the "stems" for the digging process. Use a sharp pair of bypass pruners or loppers to cut the main stalk. Aim to leave about four to six inches of the stem protruding from the ground. This remaining piece of stem serves as a helpful handle and a marker for where the tuber clump is located.
Some gardeners choose to wait about a week after cutting the stems before they actually dig. This short waiting period can help the "eyes" of the tuber become more visible. The eyes are the small bumps where new growth will emerge in the spring. If you are in a hurry because of an incoming snowstorm, you can certainly cut and dig on the same day with great success.
It is a good idea to keep your variety labels nearby during this stage. As soon as the flowers are gone, it becomes difficult to tell one variety from another. Secure a waterproof tag to the stem handle or have your crates ready and labeled. This simple step prevents confusion when you are ready to plan your garden layout next spring.
Tools You Will Need
- A sturdy garden fork or pitchfork
- Sharp pruners or loppers
- A garden hose with a spray nozzle
- Waterproof labels or markers
- Storage containers (crates, cardboard boxes, or paper bags)
- Packing medium (vermiculite, peat moss, or wood shavings)
The Art of Digging Without Damage
Dahlia tubers grow in clumps that can become quite large by the end of the season. These clumps are surprisingly heavy and can be fragile, especially at the "neck." The neck is the thin part where the tuber connects to the main stem. If the neck breaks, the tuber may not be able to sprout next year.
To lift the clump safely, start by digging a wide circle around the plant. Aim for a distance of about 12 inches away from the main stem on all sides. Using a garden fork is often better than a shovel because the tines are less likely to slice through a hidden tuber. Push the fork deep into the soil and gently pry upward.
Work your way around the entire plant, loosening the soil as you go. Once the clump feels loose, reach under the tubers with your hands or the fork to lift the entire mass at once. Avoid the temptation to pull the clump out by the stem handle. Lifting from underneath provides the support the tubers need to stay intact and healthy.
Cleaning and Inspecting Your Harvest
Once the tubers are out of the ground, they will likely be covered in garden soil. The cleaning process depends largely on your soil type and your storage preferences. If you have light, sandy soil, you can often just shake the clump and brush off the excess dirt. If your soil is heavy clay, a gentle rinse with a garden hose is usually the best approach.
When washing tubers, use a gentle stream of water. High-pressure sprays can sometimes tear the skin, which creates an opening for rot. After rinsing, take a moment to look over the clump. Remove any tubers that feel mushy or look visibly damaged. Healthy tubers should feel firm, similar to a potato.
This is also the time to trim away the "hair roots." These are the thin, thread-like roots that grow off the main tubers. While they were important for the plant during the summer, they are not needed for storage and can sometimes hold excess moisture. Use your pruners to tidy up the clump so it is easy to handle and pack.
What to Do Next:
- Rinse away heavy soil with a gentle garden hose.
- Trim off any thin, stringy feeder roots.
- Discard any tubers that feel soft or show signs of decay.
- Check that each clump still has its variety name attached.
The Importance of Curing
Curing is the process of allowing the tubers to dry slightly before they go into long-term storage. This step is vital because it helps the skin toughen up and allows any surface moisture to evaporate. If tubers are packed while they are still soaking wet, they are much more likely to develop mold or rot over the winter.
Place your cleaned tubers in a cool, dry area that is protected from direct sunlight and wind. A garage, a shed, or a covered porch works perfectly. It is important to keep the tubers off the bare concrete floor, as concrete can pull moisture out of the tubers too quickly. Placing them on a piece of cardboard, a wooden pallet, or inside a plastic crate provides good air circulation.
The curing process usually takes between 24 and 48 hours. You want the exterior of the tuber to feel dry to the touch, but you do not want the tuber itself to begin shriveling. Once the skin feels dry and the cut end of the stem looks "corked over," your dahlias are ready for their winter containers.
To Divide or Not to Divide?
One of the most common questions we hear at Longfield Gardens is whether to divide the tubers in the fall or the spring. Both methods have advantages, and the choice often depends on how much storage space you have available.
Dividing in the fall takes more time upfront but saves a lot of space. It is also easier to cut the tubers while they are still relatively soft. If you choose to divide now, ensure each individual tuber has a "crown" and at least one "eye." Without the eye, the tuber will not produce a new plant. If the eyes are hard to see, many gardeners prefer to wait.
Leaving the clumps whole is the simplest method for beginners. Whole clumps are more resilient and less likely to dry out completely during the winter. You can simply store the entire mass and divide it in the spring when the eyes are much larger and easier to identify. If you have the room in your storage area, keeping the clumps whole is a very reliable way to ensure success.
Choosing the Right Storage Medium
The goal of winter storage is to keep the tubers in a state of suspended animation. You want to prevent them from rotting (too wet) and from shriveling (too dry). To achieve this balance, most gardeners use a "packing medium" to surround the tubers.
Popular Packing Options:
- Vermiculite: This is a lightweight mineral that does an excellent job of regulating moisture. It is clean and very easy to use.
- Peat Moss: This is a classic choice that holds a small amount of moisture while allowing for air exchange.
- Wood Shavings: Pine or cedar shavings (the kind used for pet bedding) are inexpensive and provide great insulation.
- Perlite: Similar to vermiculite, this provides good drainage and prevents the tubers from touching one another.
When packing, start with a layer of your chosen medium at the bottom of a box or crate. Place the tubers in a single layer, ensuring they do not touch each other. Cover them with more medium and repeat the process until the container is full. Storing them in layers prevents a single rotten tuber from affecting the entire batch.
Finding the Perfect Storage Location
The location where you keep your tubers is just as important as how you pack them. Dahlias need a spot that stays consistently cool but never reaches the freezing point. The ideal temperature range is between 40°F and 50°F.
A cool basement, a root cellar, or an insulated crawl space are often the best spots. If the area is too warm, the tubers may try to sprout early or dry out. If the area gets too cold and the tubers freeze, they will turn to mush when they thaw. A simple indoor-outdoor thermometer can help you monitor the temperature in your chosen storage spot throughout the winter.
Humidity also plays a role. If your storage area is very dry, you may want to use plastic bins with the lids left slightly ajar. If your storage area is damp, cardboard boxes or paper bags are better because they allow the tubers to breathe. Finding the right balance for your specific home environment may take a little observation, but the results are well worth the effort.
Winter Check-ups and Troubleshooting
Gardening doesn't completely stop in the winter; it just moves indoors. It is a good practice to check on your stored tubers once a month. This small effort allows you to catch any potential issues before they become problems.
When you open your storage containers, look for two main things: shriveling and rot. If the tubers look very wrinkled and feel light, they are losing too much moisture. You can fix this by lightly misting the packing medium with a spray bottle of water. You don't want it wet, just slightly damp.
If you find a tuber that feels soft or mushy, remove it immediately. This prevents any decay from spreading to the healthy tubers nearby. If you see a small amount of surface mold, you can often wipe it off and move the container to a spot with slightly better air circulation. These quick check-ups provide peace of mind and help ensure a high success rate.
Key Takeaway: A monthly five-minute check-up can save your entire dahlia collection. Stay proactive by removing soft tubers and misting dry ones.
Preparing for Spring Replanting
As the days get longer and the ground begins to thaw, you can start looking forward to spring planting. Your stored tubers will likely start showing more prominent eyes as the temperatures rise. This is the perfect time to finish any dividing you didn't do in the fall.
Before planting, give each tuber one final inspection. They should still feel firm and heavy for their size. If you see small green sprouts beginning to form, that is a great sign that your storage was successful. You can start your tubers in pots indoors if you want early blooms, or wait until the soil is warm and the danger of frost has passed to plant them directly in the garden.
The beauty of storing tubers is that your collection of best-selling dahlias grows every year. A single dahlia plant often produces several new tubers over a summer. By following these storage steps, you will soon have enough dahlias to fill your garden and share with friends and neighbors.
Summary of the Storage Process
Storing dahlias is a satisfying way to close out the gardening season. It turns a temporary summer joy into a permanent part of your landscape. By working with the plant's natural dormant cycle, you can keep your favorite varieties safe and healthy through the coldest months.
The process is as simple as waiting for the frost, lifting the clumps with care, and providing a cool, stable environment for them to rest. Every gardener's home is different, so don't be afraid to adjust your packing materials or storage location to find what works best for you. The reward is a garden full of familiar, beautiful blooms every summer.
We are proud to be part of your gardening journey. At Longfield Gardens, we believe that every home gardener can achieve professional-looking results with a few simple steps. We look forward to seeing your dahlias thrive again next season.
"Storing dahlia tubers is one of the easiest ways to ensure your garden is even more beautiful next year than it was this year."
FAQ
Can I leave my dahlia tubers in the ground over winter?
In USDA hardiness zones 8 and warmer, dahlias can often survive the winter in the ground if the soil stays well-drained. In zones 7 and colder, the ground freezes deep enough to kill the tubers, so they must be dug up and stored indoors. If you are unsure of your zone, digging them up is the safest way to ensure they return.
What should I do if my dahlia tubers start to sprout in mid-winter?
If your tubers begin to sprout in January or February, it usually means your storage area is a bit too warm. Move the containers to a cooler spot, such as a lower shelf or a different room that stays closer to 40°F. Do not remove the sprouts, as the tuber will usually produce new ones once it is planted in the spring.
Is it necessary to wash the tubers before storing them?
Washing is not strictly necessary, but it makes it much easier to inspect the tubers for rot and to find the eyes for dividing. If you have very sandy soil, brushing off the dirt is usually enough. If you have heavy clay soil, washing is recommended because clay can trap moisture against the tuber, which might lead to rot during the winter.
Can I use plastic wrap to store my dahlia tubers?
The "Saran Wrap" or plastic wrap method involves wrapping individual, cleaned tubers tightly in plastic. This method can work well for gardeners with very limited space because it prevents the tubers from drying out and allows you to see them through the wrap. However, it requires the tubers to be perfectly cured and free of any surface moisture, or they will rot very quickly.