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Overwintering Dahlias – Digging & Dahlia Storage

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Overwintering dahlias isn’t as intense or time-consuming as you might suspect. The stunning, showy blooms are reason enough to try overwintering dahlia tubers during the coldest time of the year. It’s easy and I’ll show you how!

Dahlias are tender perennials that are generally only hardy in zones 8-10. Up here in PA, I’ve foolishly lost a pretty orange dahlia one year when I didn’t know I had to dig it up for the winter.

I’ll never make that mistake again!

And, I’m dedicated to help make sure other gardeners also don’t lose their prized dahlias!

I’ll make it as easy as possible. Just follow these tips and tricks to save and store your favorite dahlia flowers indoors over the winter!

Overwintering Dahlias in Newspaper Indoors to grow them again - dahlia tubers on newsprint
Overwintering Dahlias in Newspaper to grow them again – dahlia tubers on newsprint 2021.

Can you leave dahlias in ground over winter?

Dahlia tubers cannot withstand freezing temperatures over the duration of winter. If leaving dahlias in the ground over winter with extreme lows, the tubers will likely rot and die. Depending on where you live, you may be able to leave dahlias in-ground over winter—particularly if you’re in zones 8-10. In Pennsylvania zone 6b, we must dig up and store dahlia tubers over winter indoors.

How cold can dahlia tubers tolerate?

Dahlia tubers cannot tolerate extreme cold and freezing temperatures. While there seems to be no hard and fast rule for what temperature kills dahlias, when the soil freezes or becomes very cold, it’s too cold for your dahlia tubers. Plan to dig them up and store dahlia bulbs inside before this happens.

When to Dig up Dahlias

Knowing when to dig up dahlia bulbs is easy to keep track of each year. After the first fall frost, either the light frost or the frost that kills the plants, you should plan to dig up your dahlias. You’ll notice the plants are now darker, possibly even black, weak, falling over, and shrunken. Dig up and store dahlias before the temperatures dip down into the 20s. These killing freezes could take out your dahlias!

Digging up Dahlia Tubers: How To

Digging up dahlia tubers is way easier than I expected! After the first hard frost in the fall, plan to dig up dahlia bulbs for storage.

Choose a dry day and follow these steps for removing bulbs from soil and keeping dahlias over winter:

  1. After the frost, cut back the dead plant stems to about 2-3 inches from the soil surface.
  2. Gently loosen the soil around the base of the plant.
  3. Use a shovel to loosen the soil all around the dahlia tubers. Be very careful not to cut into any of the tubers.
  4. Dig down deep enough and lift the dahlia tubers from the soil.
  5. Carefully remove loose dirt from the bulbs.
  6. Set the bulbs aside for a couple of days in a cool, dry area before storage.

Storing Dahlias over Winter

Wintering dahlia tubers continues after digging up the bulbs. After you’ve let the tubers sit for a few days, it’s time to focus on storing dahlia tubers over winter so that they still grow healthy and strong in the spring.

Follow these tips for dahlia tubers storage over winter:

Overwintering Dahlias in Newspaper

  1. Inspect the dug dahlia tubers for signs of damage or dampness before storing. Plan to prepare the best tubers first.
  2. Carefully and loosely wrap dahlia bulbs in newspaper.
  3. Secure with masking tape.
  4. Label the masking tape with a permanent marker, indicating the type or name of the dahlia. Include the color, size, or any other specifics.
  5. Repeat for all dahlias going into storage. Place the wrapped dahlia tubers in a bin or bucket without a lid.
  6. Place a black or dark bag over top to keep it dark.
  7. Store dahlias indoors in a cool, dark place. Do not place them directly on a cement floor, which can steal moisture.
  8. Check overwintering dahlias every 3-4 weeks to ensure they aren’t shriveling or having other issues.
Overwintering Dahlia Tuber Wrapped in Newspaper in a Green Tub
Overwintering Dinnerplate Dahlia Tuber Wrapped in Newspaper in a Green Tub

Overwintering Dahlias in Plastic Bags

  1. After inspecting dahlias you’ve dug from the ground for any issues, label a plastic grocery bag with the type, color, and variety of dahlia.
  2. Gently place dahlia bulbs in the correctly labeled bags.
  3. Place the bags in a bin or bucket for overwintering storage.
  4. Top with a dark bag to help block out light and store the container in a cool, dark place.
  5. Check regularly to ensure the dahlias winter over without incident.

Wintering dahlia bulbs in plastic bags is probably the easiest method to attempt. Consider the different ways to overwinter dahlias and choose the one that works best for your needs and your comfort.

Overwintering Dahlias in Pots

Storing dahlias in pots over winter is another option to try. Over winter dahlias in pots filled loosely with peat moss, potting mix, or vermiculite.

  1. Label your desired container or flower pot with the type of dahlia, color, and size.
  2. Add a small layer of potting mix, peat moss, or vermiculite to the flower pot or container.
  3. Space out several dahlia tubers on top of the medium in the pot.
  4. Loosely add more of the material.
  5. Continue loosely fitting in more dahlia tubers to overwinter.
  6. Place the pot in a cool, dark space to winter over the dahlia bulbs.
  7. Check your dahlias once per month to watch for issues.

Caring for Dahlias over Winter: Moisture

When looking into the care of dahlias over winter, I learned that you mostly don’t want the dahlia tubers to dry out.

For this reason, some gardeners mist dahlia bulbs before storage or lightly moisten the material in the pots (vermiculite, peat, etc.).

I am a little nervous to do this as I certainly don’t want to over-moisten them. I was hoping caring for dahlias over winter would be like caring for cannas over winter – set it and forget it!

(And then find them already sprouting new growth in the spring when it’s time to plant!)

My plan is to play it by ear as far as moisture goes while I try storing tubers over winter. I am attempting the newspaper wrapped dahlias overwintering method and will check back to update the post with my findings and how I proceed.

Digging up Dahlia tubers to overwinter indoors - dahlia bulb with white plant tag
Digging up Cactus Dahlia tubers to overwinter indoors – dahlia bulb with white plant tag

The Best Way to Store Dahlias Over Winter

This is my first year truly growing dahlias seriously, so I’ve been pretty careful with them. I am hoping I’ve found the best way to overwinter dahlias and will be tracking additional options in this post.

So far, my efforts in removing tubers from the ground and overwintering dahlia bulbs indoors is going easier than expected. Fingers crossed it keeps up!

I’ve discovered the biggest piece of the puzzle is to store dahlia tubers in a cool, dry place where there’s no threat of frost.

Since I decided to wrap my dahlia tubers in newspaper for the winter indoors, I will be peeking in from time to time to check on them. I’ll post an updated photo in a month or so!

In the meantime, let’s chat in the comments about overwintering dahlias and storing tubers over winter.

Do you have any favorite methods to try? Feel free to ask any questions or share any tips in the comments. We love hearing from you!

Happy Gardening!

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