Over the summer I have read dozens of advice columns about storing dahlias. Most of them say, “A few days after a killing frost, cut down the plants.” In fact, you need not wait that long. Dahlias will have formed mature tubers after they have been in the ground for 120 days. The challenge of working after frost is that you may be digging in cold and challenging conditions. (Photo left, Jessica Becker)
A second item of garden lore is that if you leave the clumps buried after frost, you will be able to see the eyes, and division is easier. This is partially true. On some clumps, eyes will develop, but on others, they will not be apparent.
For years I did not have the time to be selective when dividing my tubers. I would cut, divide and store the tubers when I had time. It is important to make sure that each division had a tuber and a piece of the base of the stalk. Place them in plastic bags with vermiculite. Open the bag if condensation appears above the vermiculite. In the Spring, some divisions would sprout, and others would not. Storing the latter during the winter was not a big problem because I did not grow in the hundreds.
Barren soil is never good and nature does her best to avoid it. So help her out by preparing your garden for the winter. Remove debris but be sure to compost for future use. Then add already composted material if available, and you know all those leaves you just raked up? Chop them up a bit and put them on the garden. All this organic material insulates the soil from wide temperature swings which the microbial life appreciates, and it helps inhibit the spring weeds.
Save the minerals and fertilizer for the spring when the soil begins to warm up.
If you still have enough growing season to get a cover crop started, maybe give it a try instead of the above compost/leaves.
Another idea – if your stakes can make it through winter, leave them in the garden. You may be wondering how you will rototill in the spring if you do this…many dahlia growers no longer till their gardens. Those microbes mentioned above will thank you twice.
