How to Store Dahlia Tubers During the Winter Months

Are you wondering how you should store your dahlia tubers during the winter months? I’ll share some simple tips about overwintering your dahlias.

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SHOULD YOU LEAVE YOUR DAHLIA TUBERS IN THE GROUND, OR DIG THEM UP AND STORE THEM?

THAT IS THE QUESTION! LET ME CLEAR THIS UP FOR YOU.

IN MILD CLIMATES

Because I live in a more mild climate, (zone 8B) I’ve been a very lucky girl, and have only had to dig up and store my dahlia tubers ONCE in the 7 years I have had my garden. By adding a 3-inch layer of organic leave mulch to protect the dahlia tubers, I’ve been able to leave them in the ground to overwinter.

So far, so good. We had an incredibly wet winter one year, where I lost about 15% of my tubers to rot, but that’s the extent of the damage I’ve seen. I’m a little worried about the forecast for an extra cold winter season this year, so I will most likely try one of the options below to store some of my tubers this year.

I will dig up my dahlia tubers in April to split them and remove the mother tuber.

IN COLDER CLIMATES

In most areas, winters are too cold to leave the tubers in the ground. For those zones that have colder winters, dahlia plants should be cut back after the plant’s top growth dies back, or is blackened by the first hard frost. With sharp pruners or loppers, cut all but 4 inches of top growth.

The longer the tubers are kept in the ground, the more mature they will be. This will give them a better chance of surviving in storage.

Note: Remember to label your dahlias before the their blooms die, so you will be able to keep track of each tuber once they are removed from the ground.

I’ve read several articles that suggest not cutting the dahlia stems until right before digging because the stems are hollow and can collect water. This can cause crown rot and tuber decay. But for me, I don’t have much of a choice. I leave my tubers in the ground, and it rains constantly. I do try to add layers of mulch to cover the remaining stems for added protection.

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OPTIONS FOR STORING DAHLIA TUBERS

No matter what option you choose, you will need to go through these steps to start the process…

1. Use either a shovel or pitchfork, digging AROUND the dahlia clumps. Be careful not to accidentally sever the roots. I tend to use a pitchfork because the tubers are so sensitive.
2. Gently shake excess dirt off the tubers, and set aside.
3. Repeat until you’ve dug up all of your tubers.

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OPTION 1: This is the option I have used to store dahlia tubers

Rinse the tuber clumps to remove all the excess soil, and then wash by dipping them in a 5% bleach-95% water solution. After you’ve rinsed the tubers off, examine each clump to make sure that there is no damage or rot.

If the tubers have several eyes, you can divide them at this step in the process as well. Use a sharp knife or pruners to divide tubers, making sure each piece has at least one eye.

The eyes of dahlias are the set of cells that produce the next season’s plants and blooms. I have much better luck finding the eyes in the spring. So if you can’t find them in the fall, wait to divide your tubers when they may become more visible in the springtime.

To prevent the tubers from rotting, make sure they are completely dry before you store them for winter. Some gardeners suggest setting them out to dry for several weeks before putting them away for the winter. Others recommend only a couple of days. I’ve been lucky because we have a wood burning stove in our outbuilding, so our tubers dry pretty quickly.

Choose a location for storage where it’s cool and dark, and temperatures won’t go below freezing, preferably between from 40-50º F. This could be a unheated basement, closet, utility room or attic.

Pack the tubers in slightly dampened peat moss or sawdust, and then in a cardboard box or paper bag lined with newspaper. Tubers must have good air circulation, so make sure that the tubers are not touching, and have enough room for proper air flow.

I check my tubers for rot once a month throughout the winter.

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OPTION 2: My favorite blog post process

It’s not a secret. Erin at Floret Flowers really impresses me. She’s my gardening hero, and her flower farm is located in the same state, Washington.

After Erin digs her dahlia clumps up, she shakes off the excess dirt, puts the clumps into deep bulb crates and stacks them in a 40-50º room in her basement. THAT’S IT! She warns that most pros may question her tactics, but I have to tell you, it sounds like a dreamy way of doing things.

Erin says that the soil seems to keep the dahlias tubers hydrated enough to avoid shriveling. Then in mid-late March, she pulls out all the crates, rinses off the clumps and starts dividing the clumps. EASY PEASY!!!

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OPTION 3: The Saran Wrap Method

Rinse the tuber clumps to remove all the excess soil, and then wash by dipping them in a 5% bleach-95% water solution. After you’ve rinsed the tubers off, examine each clump to make sure that there is no damage or rot.

Lay them out to dry in a cool garage or basement for a day of two. Once the clumps are dry, carefully divide them and then separately wrap each tuber in a piece of Saran Wrap. Read more about dividing in my blog post about all things dahlias.

Place the wrapped tubers into plastic bulb crates, stored in a 40-50º room throughout the winter. What is great about this method, is that if a tuber were to rot, it would be completely separate from the other tubers because of the plastic.

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I hope this has given you something to think about when planning to store dahlia tubers. For more on dividing dahlia tubers, or other information about growing dahlias, you can read my blog post on All You’ve Ever Wanted to Know About Dahlias.

I’d love to hear from you. Leave me a comment and I will be sure to respond back. Thank you for being here.

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For some great tips to save plants over the winter, visit my friend Rachel of The Ponds Farmhouse. She’s using her gorgeous new greenhouse to overwinter her plants.