Introduction
There is nothing quite like the sight of a dahlia garden in full late-summer glory. Dahlias are the heavy hitters of the flower world, offering everything from palm-sized pompoms to massive dinnerplate blooms in nearly every color of the rainbow. The joy of harvesting a fresh bouquet of dahlias you grew yourself is one of the most rewarding experiences a gardener can have. Because these plants are so prolific, it is natural to want to keep that beauty going year after year.
If you live in a climate where the ground freezes, your dahlia tubers—often called bulbs—need a little help to make it through the winter. At Longfield Gardens, we want to help you feel confident about this simple end-of-season transition. While it might seem technical at first, storing dahlias is actually a straightforward process that allows you to multiply your flower collection for free. For especially big blooms, browse the Dahlia Dinnerplate Summer Lovin Collection.
This guide will walk you through the timing, the tools, and the best techniques for keeping your tubers safe and plump until spring. If you want to compare more options for next season, browse the Dahlia Assorted Enchantment Collection. By following a few basic steps, you can ensure your favorite varieties return even stronger next season. With the right approach, overwintering dahlias is an achievable and satisfying part of the gardening cycle.
Understanding Dahlia Tubers
Before you start digging, it helps to understand what you are actually looking for under the soil. While many people search for "dahlia tubers," these plants actually grow from tubers. A dahlia tuber looks a bit like a fingerling potato or a bunch of carrots joined at the top.
Unlike a tulip bulb, which contains everything the plant needs in one round package, a dahlia tuber is a storage vessel for energy. These tubers grow in a clump throughout the summer. By the time autumn arrives, a single tuber planted in the spring has usually turned into a cluster of five to twenty new tubers.
Success in winter storage depends on keeping these "storage tanks" healthy. They need to stay cool enough to remain dormant but warm enough that they do not freeze. They also need just the right amount of moisture so they do not shrivel up or turn to mush. Matching these simple needs to your home environment is the key to a successful winter.
When Is the Right Time to Dig?
Timing is one of the most important factors when learning how to store dahlia bulbs over the winter. If you need help with frost timing, the Hardiness Zone Map can help. If you dig too early, the tubers may not be fully mature. If you wait too long, a deep freeze could damage the crowns.
The First Frost Signal
In most regions, the best signal to start the process is the first "killing frost." This is the frost that turns the lush green dahlia foliage black or dark brown. While it might look sad to see your beautiful plants wilt, this is actually a helpful part of the plant's life cycle.
When the foliage dies back, the plant sends a final burst of energy down into the tubers. This helps them "cure" and prepares them for dormancy. Many experienced gardeners wait about a week or two after this first frost before they start digging. This short waiting period allows the "eyes" (the small bumps where next year’s stems will grow) to become more visible.
Watching the Weather
If you live in an area where a hard freeze happens very quickly after the first light frost, you may want to move a bit faster. You do not want the ground itself to freeze hard, as this can turn the tubers into mush. If the forecast predicts temperatures well below freezing for several nights in a row, it is time to get your garden fork ready.
Key Takeaway: Wait for the first frost to turn the leaves brown. This tells the plant to move its energy into the tubers for a successful winter rest.
Preparing the Plants for Digging
Before you lift the tubers out of the soil, you need to clear away the top growth. This makes the workspace cleaner and helps you see exactly where the center of the plant is located.
- Cut the Stems: Use a pair of sharp, clean loppers or hand pruners to cut the dahlia stems down to about 4 to 6 inches above the soil line.
- Leave a "Handle": Those few inches of stem act as a convenient handle when you are lifting the clump. They also help you keep track of where the "crown" of the plant is, which is where the tubers meet the stem.
- Label Immediately: This is the most important step for any gardener who grows more than one variety. If you grow more than one variety, the Planning Guide for Dahlias can help you compare types and heights. Once the flowers are gone, all dahlia tubers look very similar. Use a waterproof marker to write the name of the variety directly on the tubers, or tie a durable tag to the remaining stem.
How to Lift Dahlia Tubers Safely
Dahlia tubers are surprisingly fragile, especially at the "neck," which is the thin part that connects the tuber body to the main stem. If this neck snaps, the tuber usually won't be able to grow next year.
Use the Right Tool
A garden fork is generally better than a shovel for this job. If you want a visual refresher before digging, see How to Lift and Store Dahlia Bulbs. The tines of a fork can slide into the soil without slicing through the tubers. If you only have a shovel, just be sure to give the plant plenty of space.
The Lifting Process
Start by inserting your fork into the soil about 12 inches away from the main stem. You want to dig a wide circle around the plant to avoid hitting the tubers. Gently pry upward to loosen the soil. Work your way around the entire plant, loosening the earth from all sides.
Once the soil is loose, reach down and gently lift the entire clump out of the ground. Do not pull hard on the stem handle; instead, use your hands to lift from underneath the tubers. Shake off any large clumps of loose soil, but do not worry about getting them perfectly clean just yet.
Cleaning and Drying the Tubers
Once the tubers are out of the ground, they need a bit of preparation before they can go into their winter home. At Longfield Gardens, we recommend a simple cleaning process that prioritizes the health of the tuber. For more background on the plant itself, read All About Dahlias.
To Wash or Not to Wash?
There are two schools of thought on washing tubers. Some gardeners prefer to wash all the soil off with a garden hose. This makes it easier to see the "eyes" and identify any rot. Others prefer to let the soil dry and then gently brush it off.
If you choose to wash them, use a gentle stream of water. High-pressure spray can tear the thin skin of the tubers. If you have heavy clay soil, washing is often the best way to ensure the tubers are clean and ready for inspection.
The Curing Period
After cleaning, the tubers need to dry or "cure" for a few days. This allows the skin to toughen up and prevents mold from forming in storage.
Find a cool, dry spot that is out of direct sunlight and protected from frost. A garage, a covered porch, or a basement works well. Lay the tubers out on a piece of cardboard or a mesh tray. Many gardeners like to turn the clumps upside down so any moisture trapped in the hollow stems can drain out. Let them sit for 2 to 3 days until the surface feels dry to the touch.
What to Do Next:
- Cut stems to 4-6 inches.
- Dig 12 inches away from the stem with a garden fork.
- Lift from underneath to protect the fragile necks.
- Label every variety immediately.
- Cure in a cool, dry place for 2-3 days.
Inspecting and Trimming
Before packing them away, take a close look at each clump. This is your chance to remove anything that might cause problems over the winter. If you'd like a refresher on tuber anatomy, read Dahlia Tubers: What You Need to Know.
Look for any tubers that feel soft, mushy, or hollow. These are signs of rot. Use a clean, sharp knife to trim away any damaged parts. If a tuber is hanging by a thread or has a broken neck, it is best to remove it now. You should also trim off any "feeder roots"—the tiny, hair-like roots growing out of the main tubers. They will just shrivel up anyway, and removing them keeps the clump tidy.
If you notice any large areas of rot on the main crown (where the tubers meet the stem), you may need to cut that section out. Healthy tuber flesh should be firm and light-colored, much like the inside of a potato.
Should You Divide Now or in the Spring?
One of the most common questions we hear is whether you should divide the dahlia clumps into individual tubers before storing them. The answer depends on your schedule and your comfort level. If you want a fuller growing-season refresher, 8 Tips for Growing Better Dahlias is a helpful next read.
Dividing in the Fall
Some gardeners find it easier to divide in the fall because the tubers are softer and easier to cut. It also takes up much less storage space. The challenge is that the "eyes" can be very hard to see right after digging. If you divide in the fall, you must be very careful to ensure each individual tuber has a piece of the crown attached. Without a piece of the crown, the tuber cannot sprout.
Dividing in the Spring
Many home gardeners choose to store the entire clump and wait until spring to divide. By then, the tubers have naturally begun to wake up, and the eyes will be swollen and easy to spot. This takes the guesswork out of the process. The only downside is that whole clumps require larger storage containers.
If you are a beginner, we suggest storing the clumps whole. It is a safer way to ensure you don't accidentally cut off the growth points.
Finding the Best Storage Container
Your storage container needs to do two things: allow for a little bit of air circulation and hold in a tiny bit of moisture.
- Cardboard Boxes: These are a classic choice. They are breathable and easy to stack.
- Plastic Tubs: These can work well, but you must leave the lid slightly ajar or drill small holes in the sides. If a plastic tub is airtight, the tubers will sweat and rot.
- Paper Bags: Great for individual tubers or small clumps.
- Crates: Plastic milk crates or bulb crates provide excellent airflow but may require more packing material to keep the tubers from drying out.
Choosing a Packing Medium
You shouldn't just toss the tubers into an empty box. They need a "packing medium" to insulate them and regulate humidity.
The goal is to surround the tubers so they aren't touching each other. This prevents the spread of rot if one tuber happens to go bad. Popular choices include:
- Pine Shavings: Often sold as animal bedding, these are inexpensive and provide great insulation.
- Vermiculite: This mineral holds moisture well and is very clean.
- Peat Moss: A traditional choice, though it can be a bit dusty to work with.
- Coarse Sand: Good for keeping things dry, but very heavy.
At Longfield Gardens, we have found that slightly damp (not wet) peat moss or pine shavings usually offer the best results for home gardeners.
The Ideal Storage Environment
Location is the most critical factor in how you store dahlia bulbs over the winter. You are looking for a "Goldilocks" spot that is not too hot, not too cold, and not too dry.
Temperature
The ideal temperature range is between 40°F and 50°F. If the temperature stays in this range, the tubers will remain dormant. If it gets much warmer, they may try to sprout too early or shrivel up. If it drops below freezing, the tubers will be destroyed.
Common locations include:
- An unheated basement or root cellar.
- A crawl space.
- An attached garage that stays above freezing.
- A cool closet in an entryway.
Humidity
Dahlias like a humid environment (around 70-80%). If your home has very dry winter air, you may need to check your tubers more often. If they start to look wrinkled like a prune, they are getting too dry.
Key Takeaway: Think of dahlia storage like storing apples or potatoes. A cool, dark, and slightly humid spot is the secret to success.
Winter Checkups: Monitoring Your Tubers
Storage is not a "set it and forget it" task. It is a good idea to check on your tubers about once a month throughout the winter. This only takes a few minutes and can save your entire collection.
Open your boxes and feel a few tubers.
- If they look moldy or feel mushy: They are too wet. Remove any rotting tubers immediately so they don't infect the rest. Leave the lid off the box for a few days to let some moisture escape.
- If they look shriveled or feel rubbery: They are too dry. Use a spray bottle to lightly mist the packing medium with water. You don't want it to be soaking wet; just a little bit of misting is usually enough to plump them back up.
By staying proactive, you can catch small issues before they become big problems. Most gardeners find that even if they lose one or two tubers, the majority of the clump remains healthy and ready for spring.
Troubleshooting Common Issues
Even with the best care, you might run into a few challenges. Here is how to handle the most common storage hiccups.
Identifying "The Eye"
If you are looking at your tubers and can't see where they will grow, don't worry. The "eye" is a small bump located on the crown, right where the tuber attaches to the stem. In the fall, these can be almost invisible. If you can't find them, keep the clump whole. By March or April, these eyes will look like little pink or green pimples, making them much easier to identify.
Dealing with Stem Rot
Sometimes the hollow stem of a dahlia can begin to rot. This is why we recommend storing the tubers upside down during the curing phase. If you notice the stem feels soft during a winter checkup, trim it back a little further until you see clean, white tissue.
Dealing with Rodents
Mice and voles sometimes find dahlia tubers to be a tasty winter snack. If you have a known rodent problem in your garage or basement, consider using plastic crates with fine wire mesh or keeping your boxes on high shelves.
Preparing for Spring Replanting
As the days get longer and the ground begins to thaw, your dahlias will naturally start to wake up. This usually happens in late March or April. For another big-bloom option, browse the Dahlia Dinnerplate High Summer Mix.
When you see those eyes starting to sprout in your storage boxes, it is a sign that spring is around the corner. You can begin to divide your clumps now if you haven't already. Each division must have at least one visible eye to be a viable plant.
If you want an early start on the season, you can "pot up" your tubers indoors about 4 to 6 weeks before your last frost date. This gives them a head start so they bloom earlier in the summer. Just be sure to wait until the soil is warm and the danger of frost has passed before moving them out into the garden.
Simplified Steps for Storage Success
- Dig: Lift carefully after the first frost using a garden fork.
- Clean: Remove excess soil and trim away damaged parts.
- Cure: Dry in a cool, dark place for 2-3 days.
- Pack: Place in a box with shavings or peat moss, ensuring tubers don't touch.
- Store: Keep in a cool (40-50°F) dark spot.
- Check: Inspect once a month and adjust moisture if needed.
Why Storing Your Own Tubers is Worth It
Storing your own dahlias is one of the most satisfying parts of the gardening year. It allows you to grow your favorite varieties year after year without having to buy new stock. Because dahlia clumps multiply, you will likely end up with more tubers than you started with. If you want a warm-toned mix for next season, browse the Dahlia Assorted Sedona Collection. This gives you plenty of extras to trade with friends, start a new flower bed, or even share with a local garden club.
Gardening is a journey of learning and observation. Every year you store your tubers, you will learn more about what works best in your specific home environment. Whether you have a high-tech root cellar or just a corner of a cool basement, you can successfully keep these beautiful flowers alive and ready for another spectacular summer. If you prefer a softer, romantic bloom, browse the Dahlia Dinnerplate Cafe Au Lait.
At Longfield Gardens, we believe that gardening should be a rewarding and joyful experience. Taking the time to save your dahlias isn't just about saving money—it's about the excitement of seeing those familiar favorites return to your garden, bigger and better than the year before.
Key Takeaway: Storing dahlias is a simple cycle of rest and regrowth. With a cool spot and a little bit of attention, your garden will be more beautiful every year.
Summary and Next Steps
Storing dahlia tubers is a rewarding way to extend the life of your garden and expand your flower collection. By following the natural signals of the seasons and providing a stable winter environment, you can ensure your favorite blooms return year after year.
- Wait for the frost to trigger dormancy.
- Dig carefully to protect the tuber necks.
- Cure the tubers to prevent rot.
- Store in a cool, dark, and slightly humid location.
- Check monthly to ensure the tubers stay plump and healthy.
The best next step is to prepare your storage area now. Clear a spot in your basement or garage and gather your boxes and packing materials. When that first frost hits, you’ll be ready to give your dahlias the winter rest they deserve. If you are ordering new tubers, review Shipping Information.
FAQ
Can I leave my dahlias in the ground if I live in a warm climate?
If you live in USDA hardiness zones 8 through 11, you can often leave your dahlia tubers in the ground year-round. However, they must have excellent drainage, as cold, wet winter soil can cause them to rot. Many gardeners in these zones still choose to dig and divide their clumps every few years to prevent overcrowding and maintain plant health. If you want a quick zone refresher, check the Hardiness Zone Map.
What happens if I forget to dig my dahlias and the ground freezes?
In colder climates (zones 7 and below), a deep ground freeze will usually kill dahlia tubers. They are full of water, and when that water freezes, it destroys the cell structure of the tuber, turning it into mush. If you realize you forgot to dig them after a light freeze, check the tubers; if they are still firm, you may have caught them in time. For a step-by-step refresher, see How to Lift and Store Dahlia Bulbs.
How do I know if a tuber is dead in the spring?
A healthy tuber should feel firm, like a fresh potato. If a tuber is completely shriveled and brittle, or if it is soft and squishy, it is likely not viable. The most important sign of life is the "eye." If you see a small bump or a sprout near the top of the tuber, it is ready to grow, even if the tuber itself looks a bit wrinkled. If you want a broader planning refresher, read Planning Guide for Dahlias.
Do I need to use fungicide before storing dahlia tubers?
While some gardeners choose to dip their tubers in a mild fungicide solution or dust them with sulfur, it is usually not necessary for home gardeners. The most effective way to prevent rot is to ensure the tubers are properly cured (dried) before storage and to maintain the correct temperature and humidity throughout the winter. Clean tools and healthy tubers are your best defense. For order or plant-quality questions, see our 100% Quality Guarantee.
