Overwintering dahlias is not hard, and it’s well worth the effort to keep them year after year. In this post, I’ll show you three methods to try, as well as when and how to dig up the tubers, instructions for storing them, winter care tips, and much more.
No matter where you live, you can easily keep dahlias over winter, and regrow them every year. Even if you live in a frozen tundra like I do here in Minnesota.
Thank goodness, because I love dahlias. They are a gorgeous addition to my summer garden, and they add such a cool tropical feel.
Overwintering dahlias is not only convenient, it’s a huge money saver too. It means that you don’t have to buy new ones every spring. Woohoo!
Below I’m going to walk to you through three different methods of saving dahlias tubers over winter. I’ll tell you everything you need to know, and make it super simple for you.
Will Dahlias Survive The Winter?
Believe it or not, dahlias can survive the winter as long as you use the right method to overwinter them.
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Though most people buy them as annuals, they are tender perennials. That means they can live for many years in the warmer areas of zones 8 and above.
But if you live in a cold climate like I do, they won’t survive through the winter outside. So we must bring them indoors if we want to keep them.
Related Post: How To Overwinter Plants: The Complete Guide
Methods Of Overwintering Dahlias
When it comes to overwintering dahlias, you have three options to choose from. I will describe each method in detail in the section below.
- Leaving dahlias in the ground over winterOverwintering dahlias in potsDigging and storing dahlia tubers for winter
How To Overwinter Dahlias
Deciding which method to use for keeping dahlias over winter will depend on where you live, and also where you planted them.
1. Leaving Dahlias In The Ground Over Winter
If you live in zone 8 or higher, then you can leave your dahlias in the ground over winter. They will stay alive and continue to bloom year round in frost-free areas.
But the foliage will die back and the tubers will go dormant if the air temperature gets below freezing. In that case, cut the plant all the way down to the ground once it dies.
Some people in as low as zone 7 have been able to leave them in the ground in either a warm microclimate in their yard, or by giving them extra winter protection. They will survive long as the ground never freezes.
2. Overwintering Dahlias In Pots
You can leave dahlias in pots over winter too. If you want to try this method, then leave them outside until frost has killed the foliage.
Leaving them outside when the weather cools down in the fall will trigger dormancy. Once the leaves die, cut them back to the soil level, and move the container indoors before freezing temperatures arrive.
If a hard freeze is in the forecast, move the container into an unheated garage or shed to protect them.
The goal is to keep the pot cool enough so that the plant will go dormant before bringing it inside, but the bulbs won’t freeze.
3. Digging & Storing Dahlia Tubers For Winter
The most popular method of overwintering dahlias is digging up and storing the tubers. If yours are planted in the garden, then this is the method you’ll need to use. Don’t worry, it’s simple.
As the weather cools down in the fall, they will start to naturally go dormant. You can leave them in the ground until they are completely dormant, or wait until the first hard frost kills the plant.
There’s no rush to get them out, which is part of what I love about them. However, you’ll definitely need to lift them before the ground freezes.
Related Post: How To Store Bulbs For The Winter
Preparing Dahlias For Winter Storage
If your dahlias are in the ground, then follow these tips for when and how to dig them up and prepare them for winter storage.
When To Dig Up Dahlias
The good news is that you have a lot of time to dig up your dahlias. They are very forgiving, and the tubers won’t be hurt by frost.
The best time to lift the bulbs is after frost has killed the plant, but before the ground freezes. Exposing them to cold temps will trigger them to naturally go dormant, so it’s much easier to store them.
How To Lift Dahlia Tubers
To lift dahlia tubers, I like to use a garden fork, but a spade shovel would work too. In order to avoid cutting or damaging the bulbs, start digging at least a foot away from the center stem.
After you pop them out, gently shake off any excess dirt, and then cut off the stem and leaves.
There’s no need to rinse the dirt off or split the bulbs apart. Just leave them in one large clump with a little bit of soil, and they’re ready for winter storage.
Drying Dahlia Tubers Before Overwintering
Before storing dahlia tubers for winter, you should cure (dry them) first. That way there’s less risk of them rotting or molding.
Allow large clumps to dry for at least a week, and smaller bulbs only for a few days. To do that, spread them out on a shelf or the ground in a cool, dry location – I cure mine in the garage.
How To Store Dahlia Tubers Over Winter
Below I’ll give you the steps for how to overwinter dahlia tubers, and where to store them. If yours is in a pot, then you can skip the section about packing them, and just store them right in their container.
Packing Dahlia Bulbs For Storage
After digging and curing your dahlia tubers, it’s time to pack them up for storage. Some people have great success just tossing them into a paper bag, or loosely wrapping them in newspaper.
But smaller ones can dry out that way. So instead, I pack mine in a cardboard box filled with peat moss or coco coir.
You could use a similar packing material like pet bedding, sawdust, or a mix of vermiculite and perlite if you prefer. Any of those would work great too.
Place individual bulbs or clumps into the box so they aren’t touching each other, then completely cover them with packing material. As long as they aren’t touching, you can layer several tubers in one box.
Whatever you do, don’t use plastic bags or containers to store them. If they are kept too wet they will likely rot or get moldy.
Where To Store Dahlia Tubers
Where you store dahlia tubers for winter is important. Keep them in a cool, dark, and dry location that stays above freezing.
Ideally, the temperature range should stay between 50-60°F. If it’s too warm or cold, your bulbs could rot. Good options are a heated garage, unfinished basement, a cool closet, or root cellar if you have one.
Dahlia Winter Care Tips
Besides keeping them from getting too hot or cold, there’s not much you need to do to care for dormant dahlias over winter.
It’s a good idea to check on them every so often to make sure they aren’t drying out too much, or staying too wet. If you find any that are molding, then discard them so it won’t spread to the others.
On the other hand, if they seem to be drying out too much, then you can spritz them with water to rehydrate them a bit. Just make sure they aren’t too wet.
Replanting Dahlia Tubers After Overwintering
When you successfully overwinter dahlias, you might find that you’re very antsy to get them replanted in the spring. But hold on! In order for them to survive, you must do it at the right time.
When To Plant Dahlias
You should wait to plant dahlia bulbs until after all chance of frost is gone, and the ground has warmed up in spring or early summer.
Take care not to plant them too early, or they may not grow. Ideally the ground temperature should be at least 60°F (you can use a soil thermometer to check it).
How To Prepare Dahlia Bulbs For Planting
There isn’t anything special you need to do to prepare dahlia bulbs for planting. Many people have success pulling the dormant tubers out of storage, and planting them directly into the ground.
However, to wake them up faster, you could soak them in warm water first. I like to soak mine in a compost tea solution to help break dormancy, and give them a little extra boost. But this step is completely optional.
Starting Dahlia Tubers Indoors
If you’re too impatient to wait until it’s warm enough outside, you can start dahlia tubers indoors 4-6 weeks before you want to plant them.
Pot them up into a container that has drainage holes, give them a good drink of water, and place them in a warm and sunny location. Using a heat mat will help them break dormancy faster.
Below I will answer some of the most frequently asked questions about overwintering dahlias. If you can’t find your answer here, ask about it in the comments below.
Can dahlias grow indoors over winter?
While you certainly can grow dahlias indoors over winter, it’s fairly difficult to keep them thriving. They need a lot of sunlight, and are prone to bugs infestations.
You’ll likely find that it’s much easier to overwinter dahlias in their dormant state, rather than trying to keep them alive indoors.
Can you overwinter dahlias in pots?
Yes, you can overwinter dahlias in pots, and it is very easy. Once frost has killed the plant, simply cut it back, bring the container inside, and store it in a cool, dry place until spring.
Can you leave dahlias in the ground over winter?
Yes, you can leave dahlias in the ground over winter if you live in zones 8 or higher. As long as the ground doesn’t freeze, they will survive just fine outside.
How long can you store dahlia tubers?
You can store dahlia tubers for several months without any problem. However, if you store them for too long, they will eventually dry out and die. So it’s best to replant them every year, even if you can’t get to it until later in the summer.
Overwintering dahlias and storing the tubers is very easy, and a great way to save yourself some cash. Plus you’ll be able to keep your favorite varieties for many years to come.
If you want to learn all you need to know in order to successfully keep plants alive thorough the darkest and coldest months of the year, then you need my Winter Houseplant Care eBook. It will show you exactly how to keep indoor plants thriving no matter what the weather is outside. Download your copy today.
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Share your tips for overwintering dahlia tubers in the comments below.
