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.
Rachel says
That takes a lot of love and dedication, to grow tropical plants! I love to grow dahlias and have to plant them in spring and dig them all up and store them for winter, takes a lot of time to do that and in spite of all the efforts, I keep losing some bulbs each year!
Amy Andrychowicz says
I lose some of my dahlia bulbs every winter too. But I figure that’s good because it means I can buy a few new varieties. Plus it keeps the garden from getting too full.
Barb says
I live in a ranch style house with no basement no attic space either. I was wondering if I could store my Davila tubers in the pet bedding pine shavings inside a cooler so I can place it in the unheated garage over winter? I live in zone 5 Chicago suburb. I have six different types of dahlias that I would love to replant next year.
Amy Andrychowicz says
If your garage never gets below freezing, then it would work. However, if it does freeze in there, then the dahlia bulbs may not make it (if they freeze, they will die). You could certainly try it to see if it works for you. I personally would not risk it unless you have extra dahlia bulbs you can experiment with. Instead, you can keep them in a dark closet in the coolest room of your home, a utility room, or a storage room. We have a finished basement so it’s warm throughout our house. I overwinter my bulbs in the utility room, and it works great.
jfgreens says
If you give it a try, try to keep your storage container as close to an inside wall as possible to keep them a little warmer. I cooler might be too air tight and not allow for some circulation. If your garage is attached, I would think you would be good until at least 10 or 15 below outside.. For my storage I do dust with sulfur and then use a method that you would think wouldn’t work, but has been successful when placing them in my crawl space. I wrap the cut tubers in cellophane and then put a loop of blue tale with the tuber name on it. I stored about 275 tubers last year and had 2/3rds spout. (Wisconsin)
Amy Andrychowicz says
A crawl space is a great idea for storing dahlia and other bulbs!
Linda Mann says
This is my first year for dahlias. I love them. I planted mine in pots but they didn’t do as well as I had hoped. I want to take them out of the pots and store in a box with peat moss
This scares me. Lol. Would you suggest that I leave them in the pots and remove tubulars in the spring or take them out of pots and go for the box method
Amy Andrychowicz says
Either method would work just fine for storing dahlia bulbs overwinter. If you have several bulbs, why don’t you try both methods to see which one works best for you.
Frank says
I’m wondering if my dahlias need moisture? They are starting to look like prunes. They are overwintering in my garage in a dry peat mixture.
Thanks,
Frank St. Catharines ON
Amy Andrychowicz says
Yes, you can definitely give your dormant dahlia tubers a little bit of water if the peat mixture has dried out completely and the tubers are shriveling.
Jim says
Amy
Wisconsinite here. How early do you pot or pull your tubers from cold storage to get them started without having them get too leggy before going in the ground in mid to lake May?
Thanks!
Amy Andrychowicz says
I just plant my dahlia tubers directly into the ground once it’s warm enough in the spring, LOL!
Tricia ward says
I have stored my dahlias in the same peat moss for a couple years , a few have gone rotten in that box , now as I bring it out to re winterized them my box has a smell should I change the peat moss thanks tricia
Amy Andrychowicz says
Yes, I would recommend using new peat moss every year for storing your dahlia bulbs. The rot could have been caused by a fungus or disease that can survive in the peat moss, and reinfect your bulbs again year after year.
Kevin Hilton says
I’ve stored mine in vermiculite and peat moss however I’m not sure if they rot and just dry out but they seem to most time shrivel like a raisin. I’ve unfortunately lost many a tuber this way. It’s funny..I ordered some tubers from Floret and the tubers came in vermiculite but the vermiculite was moist and the tubers were all in a plastic bag. Heck even Costco sells their tubers in a plastic bag with peat moss added but not to drown the tubers. I’m not sure what I’m doing wrong.
Amy Andrychowicz says
If your dahlia tubers are drying out, then you could dampen the medium a bit before storing them. You could also check on them a few times during the winter to make sure they aren’t completely drying out, or being kept too wet (which can cause rotting or mold). Companies package bulbs for sale in different ways… but that’s not always the best way to store them long-term. 🙂
Donn says
I store the tubers in damp peat moss but I also dust them with garden sulfer. That way if there are any diseases on them or the clinging soil the whole tuber doesn’t rot
Amy Andrychowicz says
Thanks for the added tips for how you protect your dahlia bulbs from rotting during the winter!
Linda Vadas says
I dig and store dahlias for the winter. In March I plant them in pots, indoors, and they start sprouting in a few weeks. When the foliage is about 12″ tall I take cuttings and root 3 stems per pot in seed starting soil. They grow beautiful flowers, but as an annual. Cutting back also encourages fuller plant growth. Our last frost date is May 20 (seacoast of NH) and that’s when I plant the cuttings and tubers in the flower gardens.
Amy Andrychowicz says
Awesome, thanks for your added tips!
joe vandenburg says
Thanks for your tips.
maureen fodge says
This article was very informative. Thank you. I love dahlias. Some of mine are in pots and some in the ground. I pray they survive, they are not cheap to buy. I brought in some blossoms the day before major frost.So far nothing has wilted yet. So I still have flowers inside.My growing season was really strange this year.
Amy Andrychowicz says
You’re welcome! Good luck with your dahlias.
Bea Randall, of Washington State, Snohomish County says
My husband built me an insulated closet in the corner of our garage, with shelves. Then he made me some wooden boxes with air holes so the air could circulate around them. There is an electric light bulb at the top. I only turn it on when it gets down to about +10 or lower (here in the Pacific Northwest) so the closet is dark most of the time. I have found as long as I don’t put the boxes on the very bottom layer (on the concrete slab floor) they make it through the winter just fine. Sometimes I just put my dahlia tubers in the boxes, recently I’ve been covering them with very slightly damp dried moss. I don’t divide them until the spring, when they kind of fall apart anyway. Sometimes I break a few individual bulbettes off to give me space to see that I’ve gotten all of the damp soil out form in between the sections. ( Dahlias are my hobby, not a profession).
Amy Andrychowicz says
WOW!! That sounds amazing! I’m super jealous of the insulated closet your husband built you for storing dahlia bulbs for winter! I bet you could use it as a root cellar too, for crops like potatoes and carrots. Thanks so much for sharing your tips for overwintering dahlias!
Carole Biskar says
Thank you! Your comments are very helpful. I wasn’t sure when to divide the bulbs. I’ll wait until spring. I write the name and color of the bulb with sharpie before storing.
Dan Martin says
I dig and store some every year in a paper lined box filled with peat moss and put in coolest part of basement, the cooler(40-50F) the better. You can store them inside at 60F but they will start to grow a month early so you have to open the top of the box but they still transplant. Some moisture is better than letting them completely dry out.
If you have a warm basement you can make them perennials. I plant mine on the south and west side of my house about 1 foot from the house since the ground stays warmer all winter and rarely freezes. They survive the frost every year, especially if you mulch over them, put a bag of unopened mulch on the ground, or cover the ground with black plastic like I prefer, any to keep the ground warmer. Works for cannas and dahlias here in zone 5 and you have flowers a month earlier than everyone else.
Amy Andrychowicz says
Wow, I’m surprised that you can keep dahlias and cannas in the ground through the winter in zone 5, even with all that insulation. Impressive! Thanks for sharing your tips for overwintering dahlias.
Janet Vinyard says
Thanks for these tips – I love dahlias, too! When do you plant the bulbs in the spring? Blessings, Janet
Amy Andrychowicz says
You’re welcome! I plant my dahlia tubers into the garden once the ground warms up in the spring. Here in Minnesota, that’s usually sometime in late May/early June.
Amanda @ The Kolb Corner says
I love Dahlias. They are so vibrant and there are so many different color combinations!! Thank you for sharing how to overwinter them!
Amy Andrychowicz says
You’re welcome!
Carole @ Garden Up Green says
I love dahlias – its the one flower I’ve always wanted to grow but have hesitated because they tend to take up space. I want to add a bed specifically for them in my next garden. Thanks for the storing tips this was super helpful..
Amy Andrychowicz says
I added a whole bed specifically for growing annuals and tropical plants (like my dahlias) a few years ago (I call it my tropical garden)! It’s so much easier than to try to find spots to plant all those bulbs in my perennial beds, and makes digging them up way easier too. Have fun with it!
Laura @ RYG says
I went on a garden walk this summer where I saw Dahlia’s the size of a small pie plate. I guess I just have pie on the brain. Anyhow, Dahlia’s are gorgeous. Bright and cheery, I have no clue why I don’t grow them. Didn’t realize they were even a bulb!!! Just admire in other’s gardens. That needs to change! Here in the greater Niagara Falls area, the tundra certainly has set in. Fireplace is roaring and we’re watching the Hobbit and counting our Halloween Candy.
Amy Andrychowicz says
Yes, that definitely needs to change! 🙂 Dahlias are fun to grow, and overwintering dahlia tubers is super easy!