The weather is getting cooler, and while we have yet to see a frost on the farm, it’s only a matter of time. A frost will bring an end to dahlia bouquets for the year. If you purchased dahlia tubers from us in the spring, you’ve likely noticed your own plant producing fewer and fewer flowers as we moved through October.
Now is a great time to start digging and storing dahlia tubers! In the northeast, the cold winter temperatures may prevent dahlias from surviving in the ground. Some growers in southern Connecticut have had luck leaving tubers in the ground and mulching them with 8-12 inches of leaves. However, it’s a risky endeavor this far north. To ensure that we have tubers the following year, we dig out, divide, and store our tubers and replant them in the spring. You can do the same with yours. Here’s how we go about the process.
Thanks Five Fork Farms for the photo! We start digging ours this week.
Cut the plants back
In October or immediately after the first frost, whichever comes first, we cut the dahlia stalks back to about 6-12 inches. The plants should grow for at least 90 days before they’re cut back. If you, like us, planted yours in mid-May, then the plants are plenty ready by October.
Dig out the tubers
Use a garden fork to loosen the soil around the plant. Take care not to stab any of the tubers as you do so. We recommend starting to loosen the soil at least 6 inches away from the plant. Then, grab the stalks, and gently lift the clump of tubers out of the soil.
Thanks to Three Acre Farm for this photo! That’s a nice looking clump o’ tubers.
Divide and store
Next, we spray the tuber clumps with a hose to remove excess soil. Then, we divide the tubers. To know where to divide, locate eyes on the tubers. Eyes indicate the point where new growth will begin to grow next season. Cut between the eye and the center stalk to separate tubers from the rest of the plant. If a tuber does not have an eye on it, it will not grow next year. You can compost any tubers without eyes.
After dividing, we let the tubers cure for about 12 - 24 hours and then nestle them in storage bins filled with vermiculite. You can also use wood shavings.
And thanks to Columbia River Dahlias for this photo — it’s an example eye!
Don’t feel like dividing yet?
Alternatively, you can wait to divide your tubers until springtime. If you’d rather go this route, all you need to do after digging is trim back the roots from the end of the tubers and cut the stalks even further back - almost to where the tubers begin - where the stalk is no longer hollow.
Storage tips
Figuring out the best way to store dahlia tubers has been its own adventure over the years. One key lesson we’ve learned has been to move from digging to storing the tubers relatively quickly. Once exposed, the tubers begin drying. So, be sure that the tubers are stored within 2-3 days of digging.
The tubers prefer 80-90% relative humidity and temperatures above freezing but below 45°F. Check on them every couple weeks in the first month to ensure that the conditions remain appropriate. If you notice that the tubers are shriveling, your storage conditions are likely too dry. If the tubers have mold on them or show signs of rot, then the conditions are too wet. You can readjust your storage medium by spritzing it with water or by setting up a dehumidifier.
Best of luck to anyone digging dahlias this season! Come chat with us at the market if you have questions about the process. And if you decide not to dig up your dahlias, don’t worry. As long as our process goes well this season, we’ll have plenty more tubers available next spring!
-Kiersten
Until next year, dahlias!
