How Do I Store My Dahlia Bulbs for the Winter

Table of Contents

1. Introduction
2. When to Dig Your Dahlia Tubers
3. How to Dig Dahlias Without Damage
4. Cleaning and Preparing for Storage
5. The Curing and Drying Process
6. To Divide or Not to Divide?
7. Choosing the Best Packing Material
8. Creating the Perfect Winter Environment
9. Monthly Maintenance and Troubleshooting
10. Waking Your Dahlias Up in the Spring
11. Summary of the Dahlia Storage Process
12. FAQ

Introduction

The late-summer garden is often at its most spectacular when Dahlias for Sale take center stage. These generous plants provide a non-stop parade of color and texture that lasts until the very first frost. While many gardeners treat them as annuals, one of the most rewarding parts of growing these beauties is knowing you can save them for next year. Learning how to store your dahlia bulbs for the winter is a simple skill that allows you to grow your collection and enjoy even bigger, more robust plants each season.

At Longfield Gardens, we want every gardener to feel confident about the overwintering process. While dahlias are native to the warm climates of Mexico and Central America, they are perfectly happy to "hibernate" indoors in colder regions. By following a few straightforward steps, you can keep your favorite varieties safe and sound until the spring sun warms the soil again. For a closer look at especially dramatic forms, browse our Decorative Dahlias.

This guide will walk you through the entire process, from the first frost to the final packing step. We will cover the best timing for digging, how to clean and cure your tubers, and the ideal storage conditions to ensure they stay healthy. With a little bit of preparation, you can turn a single season of blooms into a lifetime of garden joy. If you are already planning next year's display, browse our Flirty Fleurs Dahlia Collections.

Successful dahlia storage relies on three main factors: timing your harvest, drying the tubers correctly, and providing a stable, cool environment for the winter months.

When to Dig Your Dahlia Tubers

Timing is perhaps the most important part of the storage process. If you dig too early, the tubers may not have enough stored energy to sprout next year. If you wait too long, a deep freeze could damage the roots. The key is to watch the weather and the foliage of the plant itself. For more growing basics, see 8 Tips for Growing Better Dahlias.

The First Killing Frost

In most parts of the country, the signal to begin the harvest is the first frost. You will notice the vibrant green leaves and stems of your dahlias turning black or dark brown overnight. This might look disappointing, but it is actually a helpful part of the plant’s life cycle. This frost tells the plant to stop putting energy into flowers and leaves and instead send all its nutrients down into the tubers for the winter.

The "Curing" Period in the Ground

After the foliage turns black, it is best to wait about 10 to 14 days before you start digging. This short waiting period is often called "curing." During this time, the "eyes" or growth buds on the tubers become more prominent, and the skin of the tubers begins to toughen up. This thicker skin acts as a protective layer during winter storage. If a very hard freeze is predicted (temperatures staying well below 28°F for several hours), you should move your timeline up and get them out of the ground sooner.

Cutting the Stems

Before you pick up your shovel, cut the stalks of the plants down to about 4 to 6 inches above the soil line. These short "handles" of stem will help you lift the clumps and keep track of where each plant is located. Many dahlia stems are hollow, so try to avoid letting heavy rain sit in the open stalks for too long before digging, as this can lead to moisture building up near the crown.

Key Takeaway: Wait for the first frost to turn the leaves black, then give the tubers about two weeks in the ground to toughen their skins before you begin the harvest.

How to Dig Dahlias Without Damage

Dahlia tubers grow in clumps that spread outward from the main stem. Because they are full of water, they can be somewhat brittle and prone to snapping. Using the right technique will help you keep the entire clump intact.

Choose the Right Tool

While a shovel can work, a garden fork (or pitchfork) is the preferred tool for this job. The tines of a fork allow you to lift the soil and the tubers more gently than a solid blade. This reduces the risk of accidentally slicing through a healthy tuber or the "neck" where the tuber connects to the main stem.

The Lifting Technique

To avoid damage, start digging about 12 inches away from the main stem. Dig in a circle around the plant, gently loosening the soil as you go. Once the soil is loose all the way around, slide your fork deep under the clump and use a levering motion to lift the entire mass of tubers upward.

If you have heavy clay soil, the clump might be quite heavy. Take your time and lift slowly. Once the clump is out of the ground, shake it gently to remove large clods of dirt. You can also use your hands to brush away excess soil, but be careful not to snap the necks of the tubers.

Immediate Labeling

This is the moment when many gardeners lose track of which variety is which. Because all dahlia tubers look very similar once they are out of the dirt, you should label them immediately. For a refresher on tuber anatomy, read Dahlia Tubers: What You Need to Know. You can tie a waterproof tag to the stem handle or use a soft pencil or permanent marker to write the name of the variety directly on the skin of the largest tuber in the clump.

Cleaning and Preparing for Storage

Once your dahlias are out of the garden, they need a bit of grooming before they go into their winter containers. Cleaning them helps prevent soil-borne diseases and pests from hitching a ride into your storage area. For step-by-step storage help, see How to Overwinter Dahlias.

Washing vs. Brushing

There are two ways to handle the remaining soil. Many gardeners prefer to use a garden hose to wash the tubers clean. A gentle spray will remove the dirt from all the nooks and crannies. This makes it much easier to see the "eyes" and check for any signs of rot or insect damage.

If you have very sandy soil that falls away easily, you can simply let the clumps dry for a few hours and then brush the dirt off with a soft brush. However, washing is generally more thorough and is recommended if you plan to divide your dahlias in the fall.

Trimming and Inspection

After the tubers are clean, take a close look at the clump. Use a pair of clean, sharp pruners to trim away the thin, hair-like feeder roots. These tiny roots will just dry up and rot during storage, so it is better to remove them now.

Check for any damaged or "mushy" tubers. If a tuber was sliced by your shovel or looks like it is starting to decay, trim it off. You only want to store firm, healthy tubers. A healthy tuber should feel like a firm potato or a carrot.

What to Do Next

• Label each clump immediately with the variety name.
• Wash away the soil with a gentle stream of water.
• Trim off the long, thin feeder roots.
• Cut away any tubers that feel soft or show signs of damage.

The Curing and Drying Process

You cannot put freshly dug dahlias directly into a sealed box. They are full of moisture and need a short period to dry out, or "cure," before they are packed away. This step prevents mold and rot from developing during the winter.

Finding the Right Spot

Move your cleaned clumps to a frost-free, shaded area with good air circulation. A garage, a shed, or a covered porch works perfectly. Avoid placing them in direct sunlight, as this can cause the tubers to shrivel too quickly.

Upside Down Drying

One of our favorite tips is to dry the clumps upside down. Place them on a piece of cardboard or in a mesh crate with the stems pointing toward the ground. This allows any water trapped inside the hollow stems to drain out rather than sitting in the "crown" (the area where the tubers meet the stem).

How Long to Dry

In most conditions, 1 to 3 days of drying is sufficient. You want the surface of the tubers to feel dry to the touch and the cut ends of the stems to look calloused or "shriveled" slightly. Be careful not to leave them out for too long—if the tubers themselves start to look wrinkled like a raisin, they are losing too much moisture and need to be packed immediately.

Key Takeaway: Dry your dahlias upside down in a cool, shaded spot for 24 to 72 hours to ensure the surface is dry and the stems are drained.

To Divide or Not to Divide?

One of the most common questions we hear is whether you should divide your dahlia clumps in the fall or wait until the spring. Both methods work, and the choice often depends on your personal preference and how much storage space you have.

Dividing in the Fall

Many experienced gardeners prefer to divide in the fall because the tubers are softer and easier to cut. Dividing now also saves space, as you are storing individual tubers rather than large, bulky clumps.

If you divide in the fall, remember that every piece must have an "eye" to grow next year. The eye is a small bump located on the crown (the neck area). If a tuber snaps off without a piece of the crown attached, it will not grow. Use a clean, sharp knife and dip it in a 10% bleach solution between different plants to prevent the spread of any potential diseases.

Waiting Until Spring

If you are a beginner, waiting until spring is often easier. In the spring, the "eyes" will begin to swell and may even start to sprout, making them much easier to identify. Large clumps also tend to resist shriveling better than individual tubers during the winter. If you have plenty of storage space, keeping the clumps whole is a very safe and effective method.

Choosing the Best Packing Material

Dahlias need a storage medium that manages moisture. If the environment is too wet, they will rot; if it is too dry, they will shrivel up and die. The goal is to provide a "breathable" buffer.

Popular Storage Media

There are several materials that work well for packing dahlias. You can choose based on what you have available:

• Peat Moss: This is a classic choice. It holds a tiny bit of moisture but stays loose and breathable. It is best to use it slightly damp (like a wrung-out sponge), not soaking wet.
• Pine Wood Shavings: Often sold as animal bedding, these are excellent for dahlia storage. They provide great air circulation and are very clean to work with.
• Vermiculite: This mineral-based material is great for managing moisture levels and is a favorite among professional growers.
• Newspaper: If you are storing whole clumps, you can simply wrap each clump in several layers of dry newspaper.

Containers for Storage

Cardboard boxes are the most "forgiving" containers because they allow for some air exchange. Plastic bins can also be used, but you must leave the lid slightly ajar or drill air holes in the sides to prevent condensation from building up inside. Avoid using airtight plastic bags, as these almost always lead to rot.

Creating the Perfect Winter Environment

Once your dahlias are packed, they need a specific environment to stay dormant but alive. Think of it as a "Goldilocks" zone—not too hot, not too cold.

Temperature is Key

The ideal temperature for dahlia storage is between 40°F and 50°F. If the temperature stays above 55°F, the tubers may think it is spring and start to sprout prematurely, or they may simply dry out. If the temperature drops below 32°F, the water inside the tubers will freeze, causing the cells to burst and the tuber to die.

An unheated (but attached) garage, a cool basement, or a root cellar are usually the best spots. Avoid placing your storage boxes near a furnace, a water heater, or against an outside wall that might get too cold.

If you aren't sure about your zone, Know Your Growing Zone: Cold Hardiness and Heat Tolerance explains USDA ratings.

Darkness and Humidity

Dahlias should be stored in the dark to keep them in deep dormancy. Humidity levels are also important; a slightly humid basement is usually better than a very dry heated room. If your home is very dry, you may need to check your tubers more frequently to ensure they aren't shriveling.

Key Takeaway: Store your packed dahlias in a dark, cool spot that stays consistently between 40°F and 50°F to ensure they stay dormant until spring.

Monthly Maintenance and Troubleshooting

Storing dahlias isn't a "set it and forget it" task. To ensure the highest success rate, we recommend checking on your tubers once a month during the winter. This allows you to catch any small issues before they become big problems.

Checking for Rot

When you open your storage boxes, look for any tubers that look dark, feel mushy, or have a foul smell. If you find one, remove it immediately and throw it away. This prevents the rot from spreading to the healthy tubers nearby. If a clump has a small spot of rot, you can often cut that section away and dust the cut with a little bit of cinnamon (a natural antifungal) before repatting it.

Checking for Shriveling

If your tubers are starting to look very wrinkled or feel soft and flexible like a rubber toy, they are losing too much moisture. To fix this, you can lightly mist the storage medium (the peat moss or shavings) with a spray bottle of water. You don't want to make it wet, just "refresh" the humidity in the box.

Dealing with Early Sprouts

If you see small green shoots starting to grow in February or March, don't panic. This usually means your storage area is a little too warm. Simply move the boxes to a slightly cooler spot. You can leave the sprouts alone; they won't hurt the plant, though they may be a bit fragile when it comes time to plant in the spring.

Safety Note on Pets and Children

It is important to remember that dahlia tubers can be mildly toxic if eaten by dogs, cats, or horses. When choosing a storage spot, make sure it is a location that is inaccessible to curious pets or small children. Keeping your storage boxes off the floor and securely closed is a simple way to keep everyone in the household safe.

Waking Your Dahlias Up in the Spring

As the days get longer and the ground starts to thaw, it will be time to think about planting. You can usually start checking for signs of life in late March or April.

Pre-Sprouting (Optional)

If you live in a region with a short growing season, you can give your dahlias a head start by "waking them up" indoors about 4 to 6 weeks before your last frost date. Place the tubers in pots with slightly damp potting soil and keep them in a warm, bright spot. This will encourage them to grow roots and sprouts so they are ready to hit the ground running once the soil is warm. For a broader care checklist, see How to Pinch and Stake Dahlias.

When to Plant Outside

The most important rule for planting dahlias in the spring is to wait for the soil to warm up. They love "warm toes." Aim for a soil temperature of at least 60°F. In most areas, this is about the same time you would plant tomatoes or peppers. Planting too early into cold, wet soil can cause the tubers to rot before they have a chance to grow.

Key Takeaway: Only plant your stored tubers outside once the danger of frost has passed and the soil is consistently warm.

Summary of the Dahlia Storage Process

Storing dahlias is a straightforward process that becomes easier every year you do it. By respecting the plant's need for a dormancy period and protecting it from extreme temperatures, you can preserve your favorite flowers for many years to come.

• Wait for the frost: Let the foliage turn black to signal the plant to store energy.
• Dig carefully: Use a garden fork and start a foot away from the stem.
• Label immediately: Never trust your memory—write the name on the tuber!
• Dry and Cure: Give them a few days in a cool, dry spot to toughen up.
• Pack correctly: Use breathable materials like wood shavings or peat moss.
• Monitor: Check monthly for rot or shriveling and adjust moisture as needed.

Success with dahlias isn't about having a "green thumb"—it's about getting a few simple basics right. We are always here to help you navigate the seasons, and we stand behind the quality of every bulb and tuber we ship. Learn more on our About Us page.

At Longfield Gardens, we believe that gardening should be a source of joy and relaxation. Saving your dahlias is a wonderful way to connect with the cycle of the seasons and ensure your garden is even more beautiful next summer than it was this year. Before you place a spring order, our Shipping Information page explains timing by zone.

We look forward to seeing your garden grow! If you want to start planning next year's display, browse our Spring-Planted Bulb Collections.

You can also choose a palette with Shop by Color - Spring-Planted Bulbs when you are ready to plan your next bed.

For larger plantings, Spring Planted Flower Bulk Buys can make it easier to fill a bed at once.

"The beauty of dahlias is that they are the gift that keeps on giving. By taking a few minutes to store them properly in the winter, you are investing in a more vibrant and spectacular garden for the future."

FAQ

Can I leave dahlias in the ground if I live in a warm climate?

If you live in USDA hardiness zones 8 through 11, you may be able to leave your dahlia tubers in the ground for the winter. However, they must be in a spot with excellent drainage, as cold, wet winter soil is the primary cause of rot. Many gardeners in these zones still choose to dig and divide them every few years to prevent the clumps from becoming overcrowded.

What is the best material to store dahlia bulbs in?

Wood shavings (pine bedding) and peat moss are widely considered the best materials for home gardeners. They strike the perfect balance between holding just enough moisture to prevent shriveling and providing enough air circulation to prevent rot. Vermiculite is another excellent professional-grade option.

Should I wash the dirt off my dahlias before storing them?

Washing is highly recommended, especially if you have heavy soil. Removing the dirt makes it much easier to inspect the tubers for damage and to find the "eyes" for dividing. Just ensure you allow the tubers to dry thoroughly for 1 to 3 days after washing before you pack them away.

Why did my dahlia tubers shrivel up during the winter?

Shriveling happens when the storage environment is too dry or the packing material doesn't hold enough humidity. If you notice shriveling during your monthly check, lightly mist the packing material with water. In the future, you might try a slightly more moisture-retentive medium like peat moss or store the boxes in a less drafty location.