I have been growing dahlias for about six years…can’t imagine a summer without them. They are fun to see in the garden, a jumble of plants in all sizes and dressed in a riot of gorgeous blossoms of all shapes, sizes, and colors. And there is nothing more cheerful in the house than a vase full of dahlias. This goes on until frost takes its toll and since dahlias are not perennials they must be dug up and stored over the winter. That is when my challenge begins.
Successful overwintering of dahlia tubers is one of the great mysteries of gardening for me. In my years of trying to find the best technique I have done everything but consult the oracle. I got instructions from growers and dahlia societies, I’ve asked other Master Gardeners, and I’ve talked with “the locals,” but there are never two sources with the same answer.
OK, here are some “approved” instructions for storage. Cut down the plants after the first killing frost, leaving a stub of about 6 inches. Dig up the tubers, turn them upside down, let them dry, then remove or wash the soil off, and dry the tubers before storing. (But some folks have success without removing the soil and I’ve even been told that in Jamestown you can leave them in the ground all winter.) Put the tubers in a cool (40 – 50 degrees. F – yes, everyone agrees about the temperature), dry, dark place in crates or cardboard boxes and nested in damp peat moss or sawdust. Or, put them in trays of dry sand or peat moss. Some say to store them in one-gallon plastic jugs (with ventilation holes) containing vermiculite, sphagnum moss, or sawdust. I even read that you should wrap the tubers in plastic wrap from the supermarket. The idea of any storage method is that you need to hold moisture in the tubers so they don’t dry out.
Now, here’s what I’ve tried…with little success, I might add (I lose 70-80 percent of the tubers I store): putting the tubers in damp peat moss nested in newspaper; putting the tubers in Perlite nested in newspaper; putting the tubers in wood chips and shredded newspaper; storing each tuber separately in a paper bag. I always use a crate to hold them.
Since the weather has been so warm I am just now digging up my tubers. Then, when they dry I will throw them in a basket, dirt and all. Why not, I’ve tried everything else. Meanwhile, I will order some replacements for next year, just in case.
So, if you have any secrets to successful dahlia tuber storage PLEASE let me know.