Putting the Dahlias Away for Winter

The Dahlias bloomed so well this summer that I didn’t want to dig them up for winter storage. If I want them to survive for next year, it’s always best to dig them up. That way I can see how large the tubers are getting and if they have any pests or disease. It also lets me divide the tubers and plan where to place them next year. I may not want them in the same place as this year.

Dahlia Mango Sunset

I use a pitchfork and carefully dig around the base of the pant. I find by using a pitchfork I don’t slice through the tubers like I could with a shovel. I just pry the soil a bit and gently lift the whole tuberous clump out of the ground. The first thing you have to do is shake off as much soil as you can. I cut the foliage off the plant and add it to my compost bin. Once you have just the clump of tubers in your hand, place them in a sunny spot to dry out for the day. This will dry up any remaining soil clinging to the tubers. Once they are dry, shake the soil off again. You want to remove as much as you can. Check carefully with your fingers between each tuber to dislodge those stubborn soil clumps.

Overwintering dahlias

Once your Dahlia tubers are ready for storage you may want to tag them so you know which ones you are saving. Above I used a plant tag cut from a yogurt container and wrote the name of the variety on it. I used a one-holed punch to make a hole and threaded a string through to hold the tag on. Just tie the tag to the end of the stems that are left.

How to overwinter dahlias

Be sure to cut back the stems on your Dahlias. They are only going to die back and you don’t need any rotting greens in your storage box. If you look at the photo above, this is not how you want to store them. There is too much stem left on the tubers.

How to overwinter dahlias

I like to cut the stems down to about an inch from the tuber. This is when you will add your tag. Now your dahlia tubers are ready for their winter home.

How to overwinter dahlias

I use a cardboard box for storing my tubers. I place a few labelled Dahlia tubers in the box and cover them with peat moss. Note that I leave them spread apart in the box. If one does rot by chance, I don’t want rot spreading to the rest. I will then add a second layer of Dahlias into the box and keep covering with peat moss.

how to overwinter dahlias

I know, this peat moss looks like a bunch of mud in this photo. It was stored in the greenhouse and got very hard and dry. Trust me, it’s a leftover bag of peat moss. I think I will be switching to horse pellets or sawdust next year. What you need is a medium that can keep the tubers moist and stop them from drying out. You want to reach a happy medium, one that stores the tubers without leaving them too damp or too dry.

How to overwinter dahlias

This is what you don’t want to keep. You don’t want to store any diseased looking tubers. I removed this large tuber from a clump when I saw the rot and tiny hole towards the bottom. You never know what little critter may be lurking in there. You also don’t want a rotten tuber as the rot could spread to all of them and ruin your plants for next season.

How to overwinter dahlias

I also discard the single tubers that fall off. If they don’t have a piece of stem and an eye where the new growth will come out, they most likely will not grow again.

How to overwinter dahlias

Well, the box is full of tubers and I am a bit short on peat moss but they should be okay.

How to overwinter dahlias

Place the lid on your box and label it. You will have to store your Dahlias in a cool garage that is frost-free. Check on them in about six weeks to be sure they are not drying out. In the spring I like to start my Dahlias in the greenhouse to get them off to an early start. If you want to plant them outside they can go in according to your climate. Here we can plant them in late April, early May.

Winter Care for Dahlias

Here is a teaser for next year. This is Dahlia ‘Ferncliff Duo’, a flower developed by Ferncliff Gardens.

How to overwinter Dahlias

This is Dahlia ‘Honka’ which performed so well this year. So I hope I have you thinking about Dahlias for next years garden. I know I will be ordering some more. They make such great cut flowers!

29 thoughts on “Putting the Dahlias Away for Winter

  1. Thank you for sharing, the Dahlias are gorgeous and it would be very hard to decide what to buy. I have had mine for only 2 years, did not take them up last year but will do that this year and also look for more.

  2. I have several dahlias I would like to save for next year. I’m unsure where to store them
    over the winter. I believe my garage freezes during the winter. Do you think I could store them in the fridge? I have a second one in the basement where I could make room if the temperature would be appropriate. (I live in New Hampshire).

    Thanks so much for your information and advice.

    1. If your dahlias are packed in peat moss inside a large box, perhaps an apple box from the grocery store, they shouldn’t freeze. I would store them in the garage and if severe frost comes, bring them inside for a short time to the coolest area of the house. I think the fridge would be too moist and cause decay on the tubers. Is your garage closed in, not a carport as that won’t work? Here it goes down to 21F in a bad winter but my dahlias are fine in the garage. Hope this helps.

      1. Yes, my garage is closed in but air gets in and I’ve had water bottles left in the car freeze. Our area gets down to 0 degrees once in a while. I’m going to try your idea of packing them in peat moss and putting them inside a large box. Thanks so much for your help…..I appreciate it!

  3. I have tried storing mine in the garage in Northern Indiana where we get well below freezing temps.. and had about 50% of them rot and turn to mush. I had them packed in boxes with wood chips in what I thought was a warm corner of the garage.. I plan on storing mine next year at a friend’s house in her unheated basement that stays around 50 degrees.

    1. No wonder people are hesitant to grow dahlias. I think the key is using something like dry peat moss that will absorb the excess moisture. I really try and dry my tubers before storing them. Its not 100% and like you I sometimes get a rotten tuber. An unheated basement sounds ideal. Just be sure to check the tubers every six weeks.

  4. Thank you for sharing your technique, as I can make some modifications to my method of overwintering my tubers from now on. My garden center suggests using VERMICULITE instead of peat or sawdust because it provides better aeration, allowing any residual moisture on the tubers to escape. My problem has been rot due to moisture hiding in the clumps during long, Alaska-winter storage. This fall, I will definitely fan out the tubers–no clumps!– and layer them with tubers not touching each other as you have suggested. I appreciate you sharing your expertise!

    1. I can see with a long winter how the dahlias would be harder to store. I like to check on my dahlias about every six weeks to make sure they are okay. Let me know how your new technique works out. If I had room in the garage I would love to try storing them in shallow boxes in a bit of shavings to see how it works. That way they would be more visible and you could see when growth begins.

  5. Hi! Really amazed at the flowers,I’ve just bought a couple of tubers n have planted them,they have begun to grow almost shrub size,I live in India right now we have monsoon ,I’ve put my pots in a balcony which gets morning sun,how long should I wait to know if they will bloom considering the weather out here!This is my first time really anxious!

    1. Thats a good question Preethi. I would ask one of your neighbours when they get blooms on their Dahlias. Here in Canada they begin to bloom around the end of June and continue blooming until first frost.

  6. Since using peat is frowned upon in the UK,because
    Of shrinking habitats for wildlife we don’t use it any
    More.Iwrap mine in newspaper,and then put them in a box,this seems to do the trick.Store them in a garage,
    Or cool greenhouse.

  7. I live in Maine. I pull them up from the dirt, brush off as much loose dirt as I can, put them in a box and put them in my unheated basement. Always have good success.

  8. When you say check on your tubers every six weeks..what do you mean? I tried storing tubers in a big box last year…had like 4 layers between peat moss like you describe. I looked about every month at them and actually threw in some water when the top layer looked try. With the peat moss the water tended to roll right off and I often ended up with a mess. Anyways when I unpacked in the spring, the top and top middle layer looked OK but the bottom layer was shriveled. I’m looking for another strategy this year for sure.

    1. Hi Kevin, Yes I find some of the smaller tubers don’t store as well so I think this fall I will place them on top of the box so they can be checked on a bit easier. Some people store their tubers in shavings and that seems to work for many of the dahlia growers. I store my tubers in early November as we get our frost around then. I think checking them in January is a good idea.

  9. Kristen, a different subject. I have saucer size dalias, they grow very tall but I don’t have any luck staking them. They always fall over. What suggestions do you have?

    1. Hi Junie, For my tall cactus dahlias, I now use a wooden stake to support the sometimes over 1″ thick stems. I use velcro plant tape to secure them. For dahlias that need extra support it may be beneficial to grow them near a fence for support.

    1. Dana, I think vermiculite would work as it will absorb moisture but not sure about perlite. Perlite tends to float and adds aeration to soils but not sure if it will wick moisture.

    1. Hi Michelle, great question. Even though the top of the plants have dried up I would leave them in the ground so the tubers continue to grow. Label where they are so they don’t get forgotten. Depending on where you live,I would take the tubers out of the ground near your first frost date. Here in the Vancouver area thats often not until early November but they can come up any time in October. I wouldn’t be surprised to see your plants send up new growth.

  10. I’m new to gardening, bought our first house this year and inherited hundreds of plants I am trying my best to learn how to care for properly. It all excites me! You say dahlias are great for cutting but I have always seen tiny little caterpillars on my table the next day. HEAPS of them.. Any suggestions in how to prevent these? I live in New Zealand but assume everyone gets these on their dahlias regardless of location. Many thanks

    1. You have me stumped Natalie as we don’t get caterpillars on Dahlias here, at least I don’t. Our biggest problem are earwigs which like to hide within the petals. It sounds like you have green looper caterpillars but I would catch a specimen and take it to one of your garden centres for identification to be sure.

  11. For many years I have dug my dahlias, left some dirt on them, and stored them in Rubbermaid bins in my basement. I don’t store them in any medium. I have an insulated basement but I don’t have a cooler place to put them. I live in Prince George, BC, about 500 miles north of the border with the US. I’ve never lost one. I leave the lid on at a small angle until about December, then check before putting the lid on properly to try to cut out the light. The dahlias tend to send out shoots which need to be broken off. I always start my dahlias inside under a grow light at the beginning of April or even a little earlier if I can’t manage to WAIT any longer. We can’t plant them out safely until the very end of May. This year, I decided to separate the tubers with a little newspaper, just in case, but have never had a problem – thus far.

    1. Thanks Wendy, it’s great to hear how you store your dahlias. I think the bit of soil on them helps to keep the dahlias hydrated. Floret Farms stores her dahlias with some soil on them until she gets time to wash them off and divide them. I have also seen people wrap each tuber in clear food wrap to keep the moisture in. Mind you I think most of us store them in clumps and divide in the spring so using the plastic wouldn’t work.

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