Short answer: To store dahlia tubers, I dig them once the plants have grown about 120 to 130 days, wash them, and let them dry in the shade. Then I divide them into small chunks, write the variety right on each tuber with a Sharpie, and pack them in a plastic tote with layers of fine vermiculite and a few air holes.
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I’m going to be honest. I was ready for this 2026 season to be over.
After the flood at the community garden where I rent a spot, my gardening year kind of came to a full stop. I lost at least half of my dahlias over there.
So the extras growing at home in my seven corten steel planters suddenly became very important. Most of them started as cuttings, four plants per container, here in my zone 6 garden in central Indiana. Here’s exactly how I dug, divided, and stored them.
Do you have to wait for a frost to dig dahlias?
Nope. The general idea is that you wait for a frost to kill the plants, then dig. That works. But it’s not the only way.
As long as your dahlias have been growing for about 120 to 130 days, the tubers should be mature enough to make it through winter storage.
There are some extra benefits to waiting for a frost. I just don’t want to wash and divide tubers with frozen fingers. We’d been waking up to the 40s all week, so I knew a frost was coming any day.
How do you dig up dahlia tubers without damaging them?
I cut the plants down first and leave a little stump. That stump gives me something to hold, and it keeps a nice hollow stem on top of the clump.
Then I dig carefully. No yanking. No dragging the clump out by the stem.
I also tagged the blooms over the last month so I’d know which plant was which. Some still ended up as mystery tubers because I either didn’t recognize the bloom or never saw one. Those might go to my local seedling sale next year.
Fun fact: these plants got zero fertilizer and maybe three or four waterings from me all season. The tubers still came out amazing.
How long should dahlia tubers dry before storing?
It depends on your conditions. I can’t tell you two hours or three days.
I washed mine right in the planters so I wouldn’t make a mess somewhere else. Then they went under my covered back porch. Outside, but out of direct sun so they don’t fry.
It was about 70 that day. I brought them in overnight in case it dropped to the 40s. By the next morning they were ready. Firm, not wrinkly, still holding some moisture.
What tools do you need to divide dahlia tubers?
Use whatever you have. Here’s what was on my table.
| Tool | Why I use it |
|---|---|
| Long skinny pruners | Reach into tight spots between tubers |
| Pink and green Hoselink USA pruners | Bigger cuts. |
| Knife | Cutting a huge clump in half |
| Pure alcohol in a cup | Disinfecting pruners between tubers |
| Sharpies, thick tip | Writing the variety on each tuber |
My tubers showed no signs of disease. I still dip my pruners in alcohol between clumps, especially between varieties. You never know.
How do you divide dahlia tubers in the fall?
This is where people freeze up. Where do you even start?
- Clean it up. I remove the little hair roots, broken necks, and anything thin, mushy, rotten, or damaged.
- Make it smaller. If the clump is huge, I cut it in half with a knife and work from there.
- Find the mother tuber. It’s usually darker than the new ones. People debate keeping it. I save it, because it can still give me cuttings.
- Leave small chunks. I’m not after perfect single tubers in the fall. If I’m unsure, I leave two or three tubers together.
- Accept losses. Sometimes a couple of tubers take one for the team. It’s okay.
Why chunks? A small chunk holds enough energy and moisture for the whole piece. Cut it too small and the little guy may not survive on its own. I can always finish splitting them in spring when the eyes are easier to see.
One Ferncliff Spice plant gave me eight divisions. Some of those could become two or three plants next year.
Also, keep your fingers out of the middle of the clump. Ask me how I know.
How do you label dahlia tubers?
I write right on the tuber with a Sharpie. Ferncliff Spice gets an “FS.” I write it on two sides just in case.
Thick tips work better for me. The bigger the better, so you can spot it fast. Wrinkly tubers are harder to write on, but as long as you can read it, you’re good.
This is my favorite trick because I don’t need a separate tub for every variety. Everything can share one container.
What’s the best way to store dahlia tubers over winter?
I use plastic totes. They’re light, easy to move, and hold a ton. Mine came from Meijer.
- Add a layer of extra fine vermiculite to the bottom (This is the HUGE bag I get in order to save money)
- Lay tubers close together, but not touching.
- Cover with about an inch to an inch and a half of vermiculite.
- Repeat the layers, leaving two or three inches of space at the top.
- Poke a few holes in the top of the tote and the lid for air, so they don’t mold.
I love extra fine vermiculite because I also use it for seed starting and to help potting mix hold moisture.
How do you keep track of dahlia tubers in storage?
I keep a note for each container with the variety, the initials, and the number of divisions. Ferncliff Spice alone has 21 divisions, which could mean 25 to 30 single tubers.
In winter, when I’m planning what to buy, I just read the note. No digging through tubs.
Watch the end of the video to see my halfway point. I was already at 58 divisions in one tote.
What’s next
In spring I’ll take these out, split the chunks, and start propagating. That post is coming.
If you want to see me find the mother tuber and make the cuts on a real clump, the full video is up top. 🌸
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