Digging Dahlias

If you’ve been following along for a while, you know dahlias and I have a love hate relationship. I don’t need to tell you that the flowers are out of this world GORGEOUS. But the storing and the late bloomers and the pests, well that’s where my frustration comes in.

Digging the tubers is straightforward, but don’t forget to label your tubers! Hopefully you have the tags we provided earlier in the season, but if not, think of next summer as a fun dahlia surprise. In the past I have labeled them by color when I don’t know their exact name.

You’ll want to wait until your tubers get hit with a frost or they’ve been in the ground for 160 days in order to fully mature. Just remember to label them before they get toasted by a frost. A hard killing frost will turn your dahlias black and you won’t know Cornel Bronze from Linda’s Baby.

We’ve put together this video and while I’m digging I discuss some specific points about storing tubers so it’s worth the 7 minute listen.

Now let's talk storage. We are likely storing significantly more tubers than a home gardener so keep this in mind when I talk about methods and results. Your storage strategy might look a lot simpler and kudos to you if it is 👏 I love this for you!

Dahlia Tuber Ideal Storage Conditions:

• Storage Temperature: 40-50°F
• Humidity: high
• Dividing: can be done before putting in storage or in the spring when the tubers are waking up
• Tubers not touching each other to prevent the spread of rot and disease
• Likely stored in some type of medium (cedar or pine pet shavings, vermiculite or peat moss)

These storage characteristics are ideal. You might not have access to all these conditions, but don’t let that stop you from trying! Everyone on the internet is going to try and sell you on their tried and true method for storing tubers, but guess what, you more than likely don’t have their exact same conditions. The moral of the story here is that you have to experiment to find what works for you!

For years I have tried storing dahlia tubers for the next gardening season and each season it’s not without mixed results. Yes, you heard that right, I have not found a storage strategy with a 100% success rate. But the good news is that with your survivors you can divide them and make more plants!!

Here’s some information about storage method’s we’ve tried in the past.

Personal Experience Storing Tubers

We’ve tried 2 different locations:

• Unheated detached garage
• Results: lost 100%, too much temperature fluctuation in a detached garage.
• If anyone has success with a minimally heated attached garage, we’d love to know your strategy!
• Unfinished basement of my house with floor temps at a steady 60°F 
  • Plastic totes filled with vermiculite, cover slightly ajar
• Things to note: we run a dehumidifier all winter long and our home was built in 1945. I have heard basements of older homes than ours have had success - see Other Success Stories towards the end of this email.
• Because we stored them in different ways, see for results based on storage media
• Results: lost 50%
• Plastic totes filled with pine shavings (aka pine pet bedding), cover slightly ajar
• Results: lost 50%
• Totes filled with peat moss
• Results: We try to avoid peat as it is not a sustainable product so we have not experimented with it, but do know that some dahlia producers do utilize it.
• Paper bag no medium on a concrete floor
• Results: lost 100% of my tubers due to shriveling thanks to low humidity and the concrete floor also sucking away any moisture

Our 2024-2025 Storage Strategy

This year, the tubers are getting some tough love (well, maybe tougher love?, I suppose) than they’ve received in past seasons. I did not wash the tubers nor am I utilizing any medium like pine shavings of vermiculite.

Here’s what we’re doing this winter:

• Dug tubers and brushed off excess soil 
• Let tubers sit in the sun for 1-2 hours and dusted off additional soil
• Lined a black bulb crate with paper bags to cover the bottom
• Set small stand up cooler (aka refrigerator) in the garage to 50 degrees. We utilize a digital temperature controller to maintain even temperature.
  
• Stacked bulb crates in cooler.
• We will check on them every month or so throughout the winter
• We will divide in the spring (late March/early April)

We’ll report back in the spring how this grand experiment works out for us!!

Other Success Stories:

We’ve heard from people in our dahlia growing community who have older homes, built earlier than my own, having great luck storing tubers in their unfinished basements overwinter. Perhaps because they don’t have any heat down there and are more like that 50°F root cellar temperature? If this is you - give it a try!

I have also heard from one person in this dahlia loving community that they left their tubers planted next to the foundation of their home in the ground over winter last year! With just a light layer of woodchip mulch! Two things, the heat from their house probably kept the tubers from freezing AND last winter was freakishly warm. 

Want to overwinter your tubers? Pick a method and try it! There is never any guarantee, but it’s worth a shot, right? Plus, in the spring you could end up multiplying your tuber stock! Trust me, you will not be mad about more dahlia plants in 2025.