Dahlias are a breeder and collector’s dream. They come in such a wide variety of sizes and colors that there is sure to be a form for any gardener. Dahlia tubers are not terribly winter hardy and will rot in the ground in many regions. They split in freezing temperatures and mold in soggy soil. It is best to dig them up and store them indoors for the cold season and then reinstall them in spring.
Tips for Saving Dahlias
There are several ways of storing dahlia tubers for winter. The crucial part of the process is cleaning and drying. However, even the best methods still require you to inspect the tubers occasionally over the course of the winter. Environmental changes in the storage location, such as increased humidity or fluctuating temperatures, can still damage overwintering dahlia tubers.
Whether you have the dinner plate sized bombshells or the dainty lollipop variety, it is important to know how to remove and store dahlia tubers. The plants are perennials in USDA plant hardiness zones 6 to 7 but will succumb in the ground in lower zones. So, your choice in colder climates is to treat them like annuals or dig them up for storage. Dahlia storing only takes a few minutes and a couple of inexpensive materials.
How to Remove and Store Dahlia Tubers
Wait until the foliage has turned yellow before digging up the tubers. This is important so that the plant can gather energy for the following year. It will store starches in the tuber which will fuel initial sprouting in summer.
Cut off the foliage and carefully dig out the tubers. Brush off excess dirt and let the tubers dry for a few days. If possible, hang them upside down when drying them so that moisture can leach out of them.
Drying is important to saving dahlias over winter and preventing them from rotting. However, they do need to keep slightly moist on the interior to keep the embryo alive. Once the skin is wrinkled, the tubers should be dry enough. Once they are dry, they are packed away.
Storing Dahlia Tubers for Winter
Gardeners differ on the best way to pack overwintering dahlia tubers. Some swear by packing them in peat moss or sand in trays in an area about 40 to 45 degrees Fahrenheit (4-7 C.). You may also try storing them in a heavy plastic bag with packing material or even a Styrofoam ice chest. Separate the roots from each other with peat, cedar chips or perlite. In temperate zones where freezes are not sustained, you can store them in a basement or garage in a paper bag.
Some gardeners advise dusting the tubers with a fungicide before packing. Whatever method of dahlia storage you choose, you will need to check the tubers occasionally to ensure they are not rotting. Remove any that might be getting rot to prevent them from affecting all the tubers.
Plant them out again after all danger of frost has passed and enjoy their brilliant tones and flashy forms.