Every year we get lots of questions about storing dahlia tubers from new dahlia growers and experienced gardeners who have had trouble storing their dahlias over the winter. Here are answers to some of our most frequently asked digging and storing questions.
Do I have to dig and store my tubers? Can I just leave them in the ground?
Your ability to leave them in-ground depends on how much rain you get overwinter, what kind of soil/drainage you have, and whether or not your ground freezes. If you do leave them over the winter, you could layer leaves or straw mulch thickly over the stubs of your stalks and cover with a tarp to prevent too much rain sitting on the clumps. If the tubers are up close to your house, the building could create a “heat sink” for them that keeps the ground from freezing. Many home gardeners leave their tubers in this way, with good results. It’s always a risk to leave them in the ground in case of unusual weather or circumstances, but as long as you’re okay with that risk, go ahead and leave them. You could also experiment with a few to see if they overwinter well before you leave all of your tubers outside.
I live in a warm climate. Should I dig my dahlias?
If you live in a place where the ground does not freeze, you don’t have to dig them! We always dig here at the farm so our dahlias don’t freeze in the earth during the winter. If you live in a tropical climate, you could cut back and dig your dahlias at any point in the year when they’re not looking as happy. Then you could either divide the tuber bounty and immediately replant, or share tubers with friends who might like to grow them. You could also simply leave them in place for a few years and then dig when plants seem less productive because their tuber clumps have become too large.
Can I store dahlias in the fridge?
We have never stored ours in a refrigerator, but I would think that as long as you don’t allow them to desiccate (which they *would* unless you wrapped them tightly in plastic or kept them in a humid box in the fridge), it could work. Of course, don’t let them freeze. If you’re asking because you live in a place that is never much below 50ºF, you could probably extend your dahlia growing season significantly. We plant our tubers in April when our nights are in the 40’s, and they are blooming by the first week of July.
Can I wrap my tubers in plastic wrap to store them?
We’ve never personally tried the plastic wrap method, but it is the same theory behind the way we store. Take a freshly dug tuber, let its skin dry, and then wrap it up tight so that the moisture stays inside where it needs to be. You could periodically unwrap the tuber to check it and then wrap it back up nice and snug and return it to its 40º-50ºF environment. If you’re having trouble maintaining the correct humidity, it might be worth experimenting with a few tubers.
I damaged a dahlia tuber while I was digging it up! Can I still store it and plant it next year?
If you inadvertently sliced into a dahlia tuber when you were digging, rest assured, you’re not alone. As long as you haven’t broken or severed the neck of the tuber, you can still store it and plant it next year. Thankfully, tuberous roots like dahlias have a wonderful ability to callous over their injuries. Treat them like you treat your other tubers and they should store just fine. We store partial tubers that have a digging fork-hole or a shovel slice with no special treatment.
What is your best tuber storage advice for a home gardener?
My first choice as a home gardener would be to place clean, dry tubers in coarse pine shavings in a plastic bin with a lid in a cool basement. My second choice would be to put the tubers in a bin in an unheated garage that does not freeze. (You can find coarse pine shavings at your local farm store, often sold as horse bedding.) Be sure to check on your tubers periodically throughout the winter to make sure they are staying cozy, and not drying out due to low humidity or molding due to too high humidity/pest damage. You could set a reminder on your phone to check them every month until the spring.
Other Dahlia Digging and Storing Resources
If you’re interested in how we store our dahlias over the winter, check out this video.