Fall Dahlia Care
Posted on: October 12th, 2019 by Aimee Sherrill
Have you had freezing temperatures in your area? With fall in full swing, we thought now is a good time to share dahlia care tips for fall. We’re starting a series of simple blog posts, that will take you through the process of taking care of your dahlias over winter and on into spring. Trust us to be your source for good information on proper dahlia care. We’ve grown dahlias for almost 2 decades in 2 different climates and are experts in dahlia care, and dahlia tubers are especially our specialty.
As we migrate from flower season, to tuber season what’s the best way to care for your dahlias right now? Here’s some tips to help you:
If you HAVE had a freeze:

Wait until your dahlia foliage looks like this before digging in the fall
Don’t do anything for at least 1-2 weeks. Leave them intact and let them die back and turn black, kind of like you let a tulip die back into the bulb before you cut them down. After get an initial hard freeze, wait least 1 week before you dig your dahlias. During this time the tuber skins are ripening and they are preparing themselves for winter. Dahlias dug too early typically will not store over winter.
If you HAVE NOT had a freeze:
Let Mother Nature do her work and let your dahlias freeze in the garden. Don’t cut them down, leave them intact and wait for the freeze, then wait at least one week after a freeze to dig your dahlias. If you live in an area that does not freeze, start to withhold water from them around November 1st, then you can dig them up around mid November and store for winter. They do appreciate a winter nap and then replant them in the spring. The trick is to find a cool area to store them in that stays about 40-50 degrees.
Why don’t I cut them down yet?
Why go through all that extra work? You’ll have to cut them down when you dig them up anyways. It’s best to leave the stalk intact and do not cut down if they have not felt a freeze yet. When you cut into a dahlia stalk, you will see that the stem is hollow. If water gets into the stem and freezes, then refreezes it damages the tubers. It’s best to leave them intact and sealed up so that doesn’t happen. Plus, it confuses them and they start to grow again underground. It doesn’t help to identify the eyes once you understand where the eye is. It’s always in the swollen part that’s attached to last years stem.
Why do I have to let them freeze first:
The challenges with dahlias is that they need to feel a freeze in order to properly end the season and cure their tubers. When we let our dahlias freeze in the fall, that tells the plant,

Frozen Dahlias at our Central WA farm in Thorp
“OK, it’s time to go to sleep for the winter.” Then the stalks turn black, the energy is returned to the tubers and the tuber skins begin to thicken as the tubers are preparing themselves for winter. It’s risky to dig your dahlias before a freeze. Dahlias dug too early have thin skins and typically do not survive the winter. They may look alright now, but usually by spring, they have shriveled to an unusable tuber.
Do I rinse off the tubers?:
We always advise to NOT RINSE your tubers with a spray hose, just tap the dirt off. Rinsing makes it incredibly difficult to get them dry enough for winter storage, which is a key factor in getting your dahlias to survive winter storage. If they are wet, they will rot, and there is no saving a rotten tuber. Plus is so much extra, unnecessary work.
Do I really have to dig up my dahlias?:
If you don’t wish to dig your dahlias, that’s ok too. For some people that just have a few growing in their yard and they are not too thrilled with the idea of digging, we always say, “Well, cut them down after they have frozen, mulch them, if they come back, Great! if they don’t, oh well just get yourself a few new tubers.” Sometimes it’s more work that just picking up $25-$35 worth of tubers in the spring.
When is the best time to order dahlias from your farm:
NOW IS THE BEST TIME to order tubers from our farm. Now is the time of year when you get the best selection of dahlias before we begin to sell out in early winter. So many new dahlias on our website this year, plus perennial favorites for your garden.
This is great advice, I never been able to properly dig up and save my dahlias over the winter. I assume your next one is how to store them?
Cary
Here is a blog post about digging and storing:
https://www.dahliabarn.com/category/digging-and-storing-dahlias/
Thanks for the common-sense advice on whether or not to dig up dahlias. I.learned a few things from the article that will make growing them easier and more fun.
You’re very welcome!
THANK YOU THANK YOU THANK YOU!
You’re so welcome!
HOW ABOUT DAHLIAS IN POTS. MANY SENIORS ARE DOING THAT NOW. I AM ONE OF THEM, AND WOULD LIKE SOME INFORMATION ON IT. THANK YOU,
You can easily store dahlias in the same pot they grew in. Wait for the freeze and the stalks to turn black, then store them in a garage or an area that stays between 40-50 degrees. An attached garage usually will hold at those temperatures. Thanks for your question!!
Thank you for this informative email I think it is probably the best info I have read about digging up tubers for winter! I have never known to wait until black or to hold back on watering! I am new to dahlias I have been growing DinnerPlate, double blooms , the smaller varieties for about 5 years! Last year I had surgery I usually wait until everything black not knowing the whys but simply because it was an easier cleaner removal of my garden Last year I had someone do it for me and it wasn’t after the first frost even! So my tubers were of no use! Now I know why! I hope you take questions #1 I saw the temperature you had for storage I have seen so many variable temps I have a finished basement runs around that temp and I don’t get musty smell or mildew is it safe to store them there? #2. What is the best to store them in some say plastic some say paper? When tubers are bought in some stores they are in plastic it’s confusing please help!
Ideal storage temps are between 40-50 degrees, closer to 40 degrees the better. You can store in plastic bags with peat moss or a cardboard box with peat moss. Thank you!
My first year with dahlias and I had four dinner plates. They grew five feet tall before there were any blooms. Is fertilizer the problem?
Too high in nitrogen fertilizers will do that, all foliage and no bloom. Switch to a granular 5-10-10 fertilizer next season. Thank you!
We never have a freeze, so just dig them up after foliage dies? It rains a lot here and haven’t done anything to them since we put them in a couple years ago. We have had a lot of trouble with blossoms turning brown and never flowering. I bought neem oil and another product for thryp, but nothing worked. Almost ready to give up. Glad I found your website. We have a dahlia farm here and will probably have to go and ask them questions. It is a place I took my mom a lot and haven’t been back since she died three years ago. If no answers that is ok. We will figure it out somehow. Love, love, love dahlias. Thanks
Your dahlias may have a blossom fungus that causes the bloom to turn brown and never open. Start spraying with neem oil or another over the counter fungicide starting in June next year. That will kill the fungus. Take a look at our blog for more articles on fall dahlia care.
https://www.dahliabarn.com/category/digging-and-storing-dahlias/