The Easiest Way to Store Dahlia Tubers
This blog post is about my favorite (and perhaps weird) way of storing dahlia tubers. Below, I provide and overview of how most people store their tubers in the winter, how I dig up my dahlias, and how this weird technique works.
Dahlia’s Winter Hardiness
Dahlias are amazing. You plant them in the spring, and you get blooms for most of the summer (usually beginning in July or August), through to the first frosty weather.
The only problem with dahlias is that they usually require special care in the winter to get them to bloom again the next year. Of course, some people do not care about this, and treat their dahlias as annuals (buying and planting every year). But if you want to get your money’s worth, this article will share with you an easy (and perhaps unusual) way to store your dahlias in the winter.
Dahlias are technically perennials and considered hardy to USDA Zone 8 (which sets the hardiness limit at 10 to 15°F, or -12 to -9 °C).They are also very prone to rotting. Anecdotally, wet winter soil and poor drainage kills the dahlias more often than the cold (so be sure to plant them in a well-drained area).
The weather can do crazy things sometimes. Mulching and planting in a well-drained area can help protect your dahlias in the winter, but that is still no gurantee. The only way to be completely sure that your dahlias will survive the winter is to dig them up and store them.
How Most People Store Dahlias in Winter
There are many different ways to store dahlias. For instance, some prefer to wash them off immediately after digging the plants up. Many people divide them immediately, while others store the whole plant. Tubers can optionally be dipped in a diluted bleach solution, or dusted with sulphur powder to prevent rotting. Typically, the tubers are then stored in a damp, clean material (like peat moss, shredded paper, or cedar shavings). Some individually wrap the tubers in plastic saran wrap. These are great methods and are preferred by many experts in the dahlia world.
The dry storage technique is what I have started calling a technique I stumbled upon by accident. It works, and is perhaps the easiest method of storing dahlia tubers.
The Dry Storage Technique
First, cut the stems to five or six inches above ground level. Next, dig the dahlia plant out of the ground. Use the stems to pick up the plant and shake the excess dirt off. Then use your fingers to scrape away the excess dirt clumped between the individual tubers. Lastly, place the whole clump into a cardboard box or plastic crate and place in storage. I store them in my basement. Perhaps a garage, attic, barn, spare room, or closet may also work for you, as long as the temperature remains between 40-50 °F/ 5-10°C.
Two or three times per winter, I will drag my garden hose down the steps and into the basement. Then, I use the handy “mist” setting found on my everyday garden hose nozzle to dampen the tubers to keep the dirt from drying out too much and shrivling up. They are pretty dry most of the time, though.
How it was discovered
When I first started growing dahlias, I had no idea what I was doing. I dug them out and tossed them into cardboard boxes. I had planned on washing them, storing them, and doing everything the way everyone told me. I just never got around to it. Turns out, the dahlias were fine. I divided and planted them in the spring. The plants were huge and healthy. The next year I did the same thing again. Why do any extra work?
How it works
I have started calling it the dry dahlia storage technique because most of the time, the tubers are pretty dry. They tend to have thicker, tougher skins than tubers stored any other way. When I mist them occasionally, and the extra soil clinging to them absorbs the water. I believe this soil traps moisture in the tubers and keeps them from shriveling up. My garden soil does lean toward clay, which coats the tubers. Maybe this technique would not be as affective in more sandy soil (please try it and let me know what happens)? Of course, you must wait to divide them until spring. As soon as you begin slicing them open and cleaning them off, they become significantly more prone to shriveling up or rotting.
Some dahlia professionals cringe when I broadcast this method. However, I do it every year. Here is a picture of this year’s dahlia blooms: evidence that the plants are prolific.
Every year, I have very few tubers rot in storage. Usually, if they do rot, it is from stacking the clumps of tubers too high, or from previously damaged tubers. Be sure to inspect for rot as you dig and break off any squishy tubers before the whole clump is moved to storage.
I was happy to learn that Floret Flowers has similarly used this technique in the past.
Why dig them at all?
If you are discouraged by the work of having to dig up dahlias in the winter, consider just leaving them in the ground. If you are at the edge of USDA Zone 7 or 8, your dahlias may get lucky and survive just fine. Again, mulch them well and be sure that the soil is well drained.
Also, some people like to treat their dahlias like annuals. This is because one plant makes so many blooms in a season, that many consider it worth the investment.
Do not let the fear dahlia tuber storage stop you from growing these amazing blooms. Experiment with the dry dahlia tuber storage technique and tell me what you learn!