Dahlia prep for winter storage
Is it true that you can sprinkle tubers with vermiculite or sulfa and then wrap them in plastic wrap for winter storage?
Hennepin County Minnesota
Thanks for the question.
Over wintering dahlias can be done. Some gardeners have great success with doing this while others have not fared as well. There are many suggested procedures and often a gardener has to experiment with several of them before finding one that works for them. Dusting the tubers with a fungicide prior to storage is a good precaution. With these thoughts in mind, take a look at the following:
Based upon my personal experience, let me add some further thoughts:
1). I store the tubers in a cool, dark spot in my basement where the temperature is slightly under 50 degrees.
2). I place the tubers in an open container (cardboard box, rubber dish pan) or bag (burlap is good) surrounded by some type of storage material. After trying many things, including not using any storage material, I now use dry peat moss. Peat moss helps to retain the moisture within the tubers but still retains a relatively dry environment around them. Whatever container I use, I do not cover it. Under no conditions should plastic bags or plastic wraps be used.
3). About every three weeks, I check on the tubers to be sure than nothing is rotting (tubers become “mushy”). If they look dry and are starting to shrivel, I mist them slightly before placing them back into the pest moss.
5). I once thought that starting tubers inside a few weeks before transplanting would provide a “head start” on things. This rarely worked and many tubers were lost after transplanting them. I now move the tubers directly from the peat moss to their outside locations once the danger of night frost has passed (mid-June here in northern Minnesota).