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.
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 save 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 winter
- Overwintering dahlias in pots
- Digging 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.
The bulbs will survive through the winter outdoors as long as the ground never freezes.
2. Overwintering Dahlias In Pots
You can store dahlia tubers 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 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 Dig Up Dahlia Tubers
To lift dahlia tubers, I like to use a garden fork, but a spade shovel would work too. 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.
Learn all you need to know about how to grow dahlias in my complete care guide.
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! You must do it at the right time or they may not survive.
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.
FAQs About Overwintering Dahlias
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 leave dahlias in pots over winter?
Yes, you can leave your dahlias in pots over winter, and it is very easy. Once frost has killed the plant, simply cut it back, leave the tubers in the pot, bring it 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.
Can you store dahlia tubers in an unheated garage?
You can store dahlia tubers in an unheated garage as long as the temperature stays above freezing. If your garage freezes during the winter, then store the tubers indoors in the coolest, darkest room of your house.
What is the best way to overwinter dahlias?
The best way to overwinter dahlias is to dig the tubers out of your garden and store them in a box packed with peat moss or coco coir. Or you can simply store potted dahlias right in their container.
When should I dig up dahlias for the winter?
You should dig up dahlias for the winter after the plant dies back from the first few hard freezes in the fall, but before the ground freezes.
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 there is to know about maintaining healthy indoor plants, then you need my Houseplant Care eBook. It will show you everything you need to know about how to keep every plant in your home thriving. Download your copy now!
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Share your tips for overwintering dahlia tubers in the comments below.
Jean says
Can I wrap dahlia tubers in newspaper for winter storage?
Amy Andrychowicz says
Yes, but they will dry out faster in newspaper than they will in peat moss or some other packing material. So check on them several times throughout the winter to make sure they aren’t shriveling too much.
Robbie says
I have about 30 dahlias planted in the ground. I will be away from home from mid September to the end of October. I would like to save the plants for next summer; should I wait until November to pull them out or should I do it before I go away? I live in zone 6.
Amy Andrychowicz says
It is best to lift dahlia tubers before the first hard freeze of the season, to avoid damage. So, if I were you, I would dig them up before you go.
Veronica says
I put my Dahlia in a pot and when it got cold took it inside but I watered it during the winter months in the pot so will it still grow back???
Amy Andrychowicz says
If the soil was wet through the winter, then you dahlia tubers may have rotted. The only way you’ll know for sure is to either dig down and see if the tubers are still firm and healthy, or give it a month or so to wait to see if it grows.
Bill Schoen says
At the end the tuber is a long root, do you cut that off when storing?
Amy Andrychowicz says
You don’t need to cut the roots off of your dahlia tubers before storing them for the winter, but you can if you want to. It really won’t affect them. Personally I leave them on because it’s one less step.
Sharon says
I didn’t get my purchased dahlia tubors planted. Can I store them til spring?
Amy Andrychowicz says
It can be tricky to keep dahlia tubers in storage for more than one year without them drying out. Check them to see if they’re shriveling, and if so, give them a little mist of water the rehydrate them a bit. Then pack them in peat moss or another similar material like I recommend above to keep them from drying out too much.
Donna Cherniak says
If you’ve left Dahlias overwinter in pots, what’s the process in spring besides watering and giving some light (before it warms up completely and putting outside).? The earth looks very compacted. Take out of pot and replant? Just add earth and compost?? Thanks
Amy Andrychowicz says
Just give your dormant dahlias a little water and some light as you said, and leave them be until it’s time to put them outside. Once they start putting on new growth, then you can either repot them or transplant them into your garden. Here’s an article that you may find helpful… How To Bring A Plant Out Of Dormancy.
Jason cziok says
Personally have never done this. But what i would do is when it when spring days warm into the 40s and 50s, is to take them out if the pot and set them out in a warm location for a few hours a day. Get them woken up and slowly acclimated to there planting environment. Then when the time to plant arrives, clean them up, cut off the water roots, and divide if desired. Plant.
Roxanne Antil says
We have had an unusually wet fall. I am concerned if that has any effect on when to lift my tubers. We had our first killing frost a few days ago. I was going to lift today but not sure if I need to wait. I did cut them back to about 6 inches. I had to dig up my calla lily bulbs early because they were starting to rot from being so wet.
Amy Andrychowicz says
I would dig your dahlia up now that you’ve had your first frost and have cut back all of the foliage. There’s no reason to leave them in any longer, and like you said, since it’s so wet, they could start to rot in the ground.
Carol Gibbons says
I dug my dahlias out of the big barrels that i planted them in. They are huge large clusters and are all stuck together, we tried soaking them in buckets of water, but that didn’t budge them, I thought I read somewhere that you should split the tubers before storing them. I also have very long roots attached to each tuber. I’m not sure what your talking about an eye like a potato, my clusters look like potatoes, I thought that was the tubers. How would I plant these in the spring without separating them? Please explain this to me.
Amy Andrychowicz says
There is no need to break apart your dahlia tubers, you can just store them in big clumps like you describe. I personally find it easier to overwinter them that way, because the large clumps won’t dry out as fast as the individual tubers can. But since you soaked them in water, make sure you let them cure for several days so they don’t mold or rot in storage. The soil around the clumps should be dry before storing them. In the spring, you can divide the individual tubers from the large clump and plant each one, or you can plant the entire clump if you prefer. The “eye” is like a small bud at the top of each tuber right below where it attaches to the main stem. As long as a tuber has an eye/bud on top, then you can separate it from the main clump, and plant it. If you can’t find an eye, then that tuber isn’t mature enough to be divided.
Patrice says
I live in MA zone 6b. If I overwinter my potted dahlias in their pots:
– should I let the pots/soil dry out completely before the first frost? Then cut back,etc.
– what temp range should I keep them at inside? I have a below grade garage or basement to chose
from for storing.
– should I cover the pots to keep them in complete darkness?
Amy Andrychowicz says
Yes, you can stop watering your potted dahlias as the temps start to cool down in the fall to help trigger dormancy. The temperature in the place where you choose to store them should remain above freezing at all times for sure, but ideally it should stay between 50-60°F. No need to cover them unless your storage area is bright all the time. Occasionally turning on the garage or basement light won’t be a problem for you dormant dahlias, but they should remain in darkness most of the time.
graham cripps says
I have lifted my dahlias and have several ‘clumps’ of healthy looking tubers. How do I split them to get more plants ? I have heard about looking for ‘eyes’ and sharp knives but would appreciate any advice
Amy Andrychowicz says
You can divide your dahlia tubers either in the fall before overwintering them, or wait until spring before you plant them. The “eyes” are basically just buds, similar to a potato. They are located at the point where the tuber is attached to the main stem. As long as the tuber has a healthy bud (eye), you can divide it at that point. Hope this helps!
De says
Sound super easy, however NOT to sound absolutely lazy but it’s the end of Oct. right now and I’m in zone 7b. Do I need to over winter these guys? Note they did come back this past summer all on their own. So before I dawn the duck boots, layer in mosquito spray and move all the wood chips what do you say?
Amy Andrychowicz says
Dahlia tubers will survive the winter in your garden as long as the ground doesn’t freeze. So, if you live somewhere that’s warm enough, then there’s o need to dig them up.