10 Tips for Overwintering Dahlias (Mistakes to Avoid)

As the colder months approach, protecting your beautiful dahlias from the frosty weather becomes a top priority.

Overwintering dahlias is an essential task for every gardener to ensure that these vibrant, eye-catching flowers continue to brighten up your garden come springtime.

In this article, we’ll share 10 helpful tips to guide you through the process and make it as easy as possible.

You might be feeling a bit overwhelmed if you’re a first-timer, but don’t worry! With a little bit of patience and these expert suggestions, you’ll master the art of overwintering dahlias in no time.

Whether you live in a mild or more harsh climate, these tips will give your plants the best chance of survival and flourishing in the next growing season.

So, grab your gardening gloves and let’s get started on preserving those lovely dahlias of yours.

Dahlia Overview

Dahlias are beautiful, versatile flowers that can liven up any garden. They come in various shapes, sizes, and colors, giving you plenty of options to fit your personal style. Dahlias bloom from mid-summer to the first frost, providing months of enjoyment as you watch them thrive.

To get the most out of your dahlias, it is essential to understand their specific needs. Dahlias prefer well-draining soil, full sun exposure, and protection from strong winds. As you plan your garden, consider these factors to help your dahlias flourish.

One crucial aspect of dahlia care is overwintering, especially in colder regions where freezing temperatures might damage your precious plants. By following a few tips, you can ensure they not only survive the winter but return even more beautiful the following season.

Here are ten tips to help you overwinter your dahlias:

  1. Wait for the first frost: Before digging up your dahlias, let the first frost blacken the plant’s foliage. This signals the plant to begin its dormancy process.
  2. Carefully dig up the tubers: Use a garden fork or shovel to gently lift the tubers out of the ground, taking care not to damage them.
  3. Remove excess soil: Shake off any excess soil from the tubers, and use a soft brush or cloth to clean them further if needed.
  4. Trim the stems: Cut the stems back to about 4 inches long to help prevent rot and promote new growth in the spring.
  5. Allow tubers to dry: Lay the tubers in a well-ventilated area for a few days, allowing them to dry and harden.
  6. Label your tubers: If you have multiple dahlia varieties, use a permanent marker or weatherproof label to identify them.
  7. Store in a breathable container: Place your tubers in a box or crate filled with peat moss, vermiculite, or sawdust, ensuring they are not touching each other to prevent rot.
  8. Check humidity levels: Monitor the humidity in the storage area, maintaining a level between 40% and 60% for optimal results.
  9. Keep tubers in a cool, dark place: Store your tubers in a location with a temperature between 40-50°F (5-10°C). Avoid areas with drastic temperature fluctuations.
  10. Inspect tubers periodically: Check on your stored tubers every few weeks, looking for signs of rot or damage. Remove any affected tubers to prevent further issues.

By following these ten tips, you can successfully overwinter your dahlias and enjoy their stunning beauty in your garden for years to come.

When to Start Preparing for Overwintering

Understanding the Frost Timeline

Knowing when to start preparing your dahlias for overwintering is crucial, so it’s important to understand the frost timeline in your region. Frost can damage or kill your dahlias, so you need to start preparing before the first frost occurs.

Generally, dahlias are more likely to get damaged by frost if they’re left in the ground after the first frost. To find out when the first frost typically occurs in your area, you can check your local weather websites or ask fellow garden enthusiasts.

Once you know when the first frost is expected, make a note of it on your calendar. It’s a good idea to start preparing your dahlias for overwintering about 2-3 weeks prior to the anticipated first frost date. This will give you enough time to complete all the necessary tasks without risking damage to your plants from an early frost.

During this preparation period, you should:

  • Gradually reduce the amount of water you give your plants: This will help encourage dormancy and make it easier for your dahlias to adapt to the colder temperatures.
  • Remove any dead leaves, buds, or flowers: This helps prevent diseases from spreading during winter storage.

By following these steps and keeping an eye on the frost timeline in your area, you’ll be well-prepared to overwinter your dahlias and help them thrive in the coming spring.

Materials Needed for Overwintering

To successfully overwinter your dahlias, you’ll need a few essential materials on hand. These items will help ensure the health and longevity of your plants throughout the winter months.

Containers: You’ll need several breathable containers of appropriate sizes to store your dahlia tubers. These can be plastic or cardboard boxes, or even paper bags. Make sure there are drainage holes to prevent excess moisture buildup.

Peat moss, vermiculite, or perlite: These materials serve as a protective layer for your tubers. They help maintain the right moisture balance and provide insulation from extreme temperatures. For your dahlias, choose any one of these materials that is readily available to you.

Garden tools: You’ll need some basic gardening tools, such as a spade or trowel, for lifting the dahlia plants out of the ground. Additionally, a soil thermometer can be helpful to verify soil temperature before digging up your tubers.

Labels: It’s important to label your containers with the corresponding dahlia varieties. You can use waterproof markers, plant tags, or any other durable labeling method to help keep track of your tubers.

Wire mesh or hardware cloth: This material can be used to create barriers around the storage area to keep rodents and other pests away from your stored tubers.

Remember, having all the necessary materials and tools before starting the overwintering process will make the task easier and more enjoyable. Most importantly, it will help you provide the best care possible for your beautiful dahlias throughout the winter months.

Step by Step Guide to Overwintering Dahlias

Uprooting Dahlias

To begin overwintering your dahlias, start by uprooting the plants after the first frost. Follow these steps:

  1. Cut the stems back to about 6 inches above the ground.
  2. Carefully dig around the tuber clumps, making sure not to damage the tubers.
  3. Gently lift the clumps out of the ground and shake off the excess soil.

Storing Dahlias

Once your dahlias are uprooted, it’s time to prepare them for storage. Here’s how to do it:

  1. Let the tubers air-dry for a day or two in a well-ventilated space.
  2. Remove any remaining soil and loose roots with your hands or a soft brush.
  3. Label the tubers with their variety name, if desired.
  4. Wrap each tuber clump in newspaper or place them in a paper bag filled with dry sawdust, peat moss, or vermiculite.
  5. Store them in a cool, dark location with temperatures between 40-50°F (4-10°C).
Storage MethodMaterialIdeal Temperature
NewspaperPaper40-50°F (4-10°C)
Paper BagsSawdust40-50°F (4-10°C)
Peat moss40-50°F (4-10°C)
Vermiculite40-50°F (4-10°C)

Checking Dahlias During Overwintering

Throughout the winter, make sure to check on your stored dahlias periodically. Keep an eye out for these signs:

  • Mold or rot: If you notice any mold or rot, remove the affected parts and treat the tuber with a fungicide.
  • Desiccation: If the tubers seem to be drying out, slightly dampen the storage material.
  • Shrinking: If tubers are shrinking, they may require a bit more moisture in the storage material.

By following this step-by-step guide, you should be able to successfully overwinter your dahlias and have them ready for replanting in spring.

Remember to maintain a friendly tone when caring for your plants, as they can sense your love and attention!

Common Mistakes to Avoid

Overwatering: The most common mistake is overwatering your dahlias. Dahlias only need water during their growing season and should not be watered during winter dormancy. Too much moisture could lead to tuber rot or disease. Make sure to let the soil dry between waterings.

Ignoring frost warnings: Another mistake to avoid is not paying attention to frost warnings. Dahlias are sensitive to frost, and if left unprotected, they can be damaged. Be sure to lift your tubers and store them indoors before the first frost arrives.

Improper storage: Dahlias need proper storage conditions to stay healthy during winter. Avoid exposing them to extreme temperatures, as this can lead to damage. The ideal storage area is a cool, dry, and dark place with a temperature between 40 and 50 degrees Fahrenheit.

Skipping labeling: It’s easy to forget which dahlia variety is which when you’re dealing with many tubers. Label your tubers with the variety name before storing them. It helps ensure you plant the right dahlias in the correct spots next year.

Not dividing tubers: Over time, dahlias will produce more tubers, and when left unchecked, eventually, the clump could become overcrowded and less productive. Divide the tubers before storing them for the winter.

Keep these tips in mind, and you’ll be well on your way to nurturing healthy, vibrant dahlias come next spring!

Advanced Tips for Overwintering Dahlias

It’s important to treat your dahlias with care during the winter months, and with these advanced tips, you’ll be well on your way to successful overwintering.

First, make sure to lift your dahlia tubers from the ground after the first frost. To do this, carefully remove the soil around the base of the plant. Gently lift the tuber with a digging fork, taking care not to damage the roots. Shake off any excess soil before storing.

Next, store your lifted tubers in a cool, dry place. A temperature of around 45-50°F (7-10°C) is ideal. To store them, follow these steps:

  1. Lay out some newspaper.
  2. Place your tubers on the newspaper, making sure they’re not touching each other.
  3. Lightly cover them with peat moss, wood shavings, or vermiculite to retain moisture.
  4. Check on your tubers every few weeks, removing any that show signs of decay.

Labeling your dahlia tubers is a great way to keep track of the different varieties you have. You can use a waterproof marker to write directly on the tuber or attach a plastic tag with a wire loop.

During storage, be sure to monitor humidity levels to prevent mold growth. Aim for a humidity level of 50-60%. You can use a hygrometer to measure the humidity in the storage area. If the humidity is too high, it is a good idea to run a dehumidifier.

Lastly, trim back any damaged or rotting portions of the tuber before storing to avoid the potential spread of disease. Using a clean and sharp pair of garden shears, cut away any unhealthy or mushy areas of the tuber.

Following these tips will help ensure your dahlias remain healthy and in good condition, ready to be replanted for the next growing season.

Looking Ahead: Preparing Dahlias for Spring

As winter comes to an end, it’s time to start thinking about getting your dahlias ready for the spring season. Here are a few essential steps you need to take to ensure that your lovely flowers will thrive once the warmer months arrive.

Firstly, make sure to carefully remove your dahlias from storage. Check them for any signs of rot, mold, or damage. If any damaged or diseased tubers are found, discard them immediately to prevent the spread of infections to other healthy tubers.

It is essential to divide your dahlia tubers before planting. Gently separate the tubers by cutting through the crown, ensuring that each division has at least one eye attached to it. This will promote good growth and allow you to increase the number of plants in your garden.

Prepare the planting site by choosing a location that receives plenty of sunlight and has well-drained soil. Remove any weeds, debris, and large stones from the area. A week before you plant your dahlias, enrich the soil by adding a generous amount of compost or well-rotted manure. This will provide adequate nutrients needed for optimum growth.

When planting your dahlias, dig a hole about 6 to 8 inches deep, position the tuber with the eye facing upwards and cover it with soil. Ensure that the eye is not more than 1-2 inches deep in the soil. Dahlia tubers should be spaced about 2 feet apart to provide enough room for their growth.

Water your dahlias regularly throughout the growing season, but take care not to overwater, as this can lead to diseases. Feed your dahlias with a balanced, slow-release fertilizer according to the label instructions.

Staking your dahlias is an essential step, especially for larger varieties that can have heavy blooms. Install sturdy stakes at the time of planting. As the plants grow, make sure to tie them securely to the stakes to offer support and prevent them from snapping in strong winds.

By following these few simple steps, you’ll be well on your way to enjoying beautiful, healthy dahlias in the spring. Your garden will come alive with vibrant colors and amazing blooms, making all the hard work worth it.


Overwintering dahlias is a simple process that ensures your beautiful flowers return year after year. By following these 10 tips, you’ll provide your dahlias with the care they need to thrive during winter months:

  1. Gather Supplies: Purchase or collect storage containers, peat moss or vermiculite, a garden fork, and pruning shears.
  2. Wait for Frost: Allow dahlias to experience a light frost as this signals to the plant that it’s time to go dormant.

In the next steps, you’ll prepare the tubers for storage and place them in a dry, cool environment.

  1. Dig up Tubers: Use a garden fork to gently loosen the soil around the plants, then carefully lift the tubers out of the ground.
  2. Clean and Trim: Rinse off excess soil, but avoid soaking the tubers. Use pruning shears to trim off compromised sections and old roots.

Now, let’s focus on packing and storing the tubers for the winter months.

  1. Label and Pack: Make sure to label your storage containers with the variety and color of the dahlias. Place the tubers in layers with peat moss or vermiculite in between each layer.
  2. Store Properly: Place your containers in a location with temperatures between 40-50°F (4-10°C) and low humidity, such as a basement or garage.

Throughout the winter, it’s vital to check on the tubers and address any issues that arise.

  1. Monitor for Issues: Inspect your tubers periodically for rot, mold, or any other issues. Remove any affected tubers and adjust your storage environment as needed.
  2. Hydrate as Needed: If tubers appear to be shriveling, add a small amount of moisture to the storage medium.

Finally, as winter comes to a close, it’s time to prepare your dahlias for replanting in the spring.

  1. Divide Tubers: Inspect the tubers for new eyes, and separate the clumps into individual plants with at least one eye per tuber.
  2. Plant in Spring: When the soil temperature reaches 60°F (16°C), and there’s no risk of frost, it’s time to plant your dahlias.

By following these guidelines, you’ll ensure that your dahlias are protected during the winter, and you can enjoy their vibrant blooms again next year.