To help readers with storage of their favorite dahlias, I am creating a series of posts on digging, dividing and storing dahlias for the winter. The first post of a few weeks ago let you in on what you needed to know to prepare to overwinter your dahlia tubers. Now, that you are ready, it is time to really get down to business.
As noted in the previous post, it is best to wait about two weeks after your killing frost to begin digging dahlia tubers. Some gardeners prefer to use a garden fork to gently loosen the soil under the tuber and lift. I, in my “plow ahead” style simply pull out my trusty “shovel” and begin digging. Well, it is not quite that simple… one of the things you must know is that your dahlia was not only producing a ton of blooms for you to enjoy above ground, but was also putting in quite a bit of work in creating a bunch of tubers underground. While you might have planted a single tuber, which looked anything from a fingerling potato to an unusual sweet potato, you will likely find, when you dig, a sizable “clump” of tubers, perhaps 12” to 18” in diameter. SO (note this part well) when you put your shovel to the ground, be sure to dig at least 9”, and maybe more, away from the old stems. Chances are, the tubers now extend this far out in every direction. Dig a bit on one side. Then dig a bit on another side. Dig around until you can loosen the clump from the soil and lift it up from underneath with your shovel. Next, flex your muscles a bit, and prepare to lift your dahlia clump with a bit of soil.
What next? It’s time to find the hose! I spray down the tuber clumps with hose water on a gentle jet/spray. I want to rinse the soil off, but not damage the soft out skin surrounding the tubers. If you look closely at the area near the cut stalks, you might see some very small bumps, which appear to be raised, and slightly darker in color than the surrounding plant material. These are the eyes of the tuber. Not every tuber has eyes. You want to store tubers that do have eyes since these will be the new shoots for your next year’s plant. Stay tuned for dividing information in my next post. Because I dig so many dahlias each year, I often do not divide immediately after digging. I used to store the entire clump of tubers and either plant the entire clump the following spring, or do my dividing in the spring. I now prefer to divide tuber clumps in the fall, partly because I have a bit (not much) more time in the fall to do this task than I do in the spring, and partly because the eyes are easier for me to see in the fall.