How to Store Dahlia Tubers

Here's how I store my dahlia tubers for the winter. I'm sure there are other effective ways, but this has worked well for me for many years. You always lose a few, but I've lost fewer this way than any other method I've tried.

I always wait until the frost has killed the foliage. I've been told that the death of the foliage signals dormancy in the tubers, so they'll keep better than if you dig them when the foliage is fresh. However, do not delay until the ground freezes, because the tubers will be destroyed if they freeze.

Cut the stem down to about a foot. This serves as a handle as you wash it and trim it.

Using a fork (or very carefully if you only have a shovel) loosen and lift the entire clump of tubers. The clump is often surprisingly large, so be sure to sink your fork far enough from the stem that you don't damage the tubers.

Lay it on the grass and rinse it with a stream of water until all loose dirt is gone.

Cut off the fine hair roots, as well as the long stem. Leave just an inch or two of stem—enough to keep the tubers together. If any of the tubers are broken at the "neck", just discard them—they usually won't have any bud eyes on them.

Using a permanent pen, write the name of the dahlia on the side of a regular plastic grocery bag. If you've got a plant tag, lodge that among the roots, too. Here's how the completed roots should look after being cleaned up. I don't wait for them to dry, and I certainly would never leave them laying around for a day or two.

Place a handful of dry sawdust or dry peat moss in the bottom of the bag. (I prefer sawdust).

Place the tuber in it. As long as the sawdust or peat moss is dry, it doesn't matter if the tuber is still wet.

Then put another scoop of dry sawdust on top. It doesn't have to be completely covered, but mostly.

I store the bags in my garage, in a closed cupboard against the house-side wall. It's important that they don't freeze, but they do stay cool. Note that the top of the bag is left open; if you close it, your tubers may get moldy. (Some people use a fungicide on them before storage. I tried that once, and they rotted worse than they've ever done. Go figure.)

Some of the tubers will break off, either in digging or handling. Don't worry too much about it. You'll have enough.

Some time in January or February I check each bag. If there are moldy or diseased tubers, cut them off and discard. I've occasionally seen one looking a bit wrinkly and dry, and I'll spray or sprinkle just a little water on them.

In March, I bring the bags into a warmer place like the basement, and look for buds. At this point the tubers can be divided—all you need is one bud to grow a plant. I never plant the whole clump. Usually there are enough to give to all your friends and neighbors.

Dahlias tend to bloom late in the season, so if you want an extra month, start them early in pots indoors; then set them out after the danger of frost is past.