How to store Dahlias over winter you ask? The Dahlias bloom beautifully for months and then one day Old Man Winter blows in. (It is snowing out as I write this.) He plans to stay months with you. Eeek! No surprise really he comes every year regularly. I just don’t want his visit to destroy your Dahlia crop that you’ve invested your precious time and energy in, not to mention money, caring for them.
I live in Zone 6 or 7 depending on the year or who you talk to. Some years have even felt like a cold zone 5. The ground has not frozen solid for a few years now and hopefully won’t this year. However, the Dahlias stalks are still cut back to 3-4 inches above the ground, the tuber cluster dug out, sprayed thoroughly with a hose to remove soil, allowed to dry several hours and then divided and stored. It’s this storing part I want to talk about.
There are always going to be people who say their way is the right way to store Dahlia tubers. With that said people come up with various other ways to safely store Dahlias. An example is a gardener saying that you should store tubers in peat in a tote but leave the lid ajar, don’t seal the tote tight. Another person comes along and they say they wrap each tuber tightly in plastic wrap and store in containers. How opposite can you get?
Dahlia tubers “rest” during cold weather and they don’t want to dry out and shrivel. They don’t want to rot from too much moisture. They don’t want to have to take off running/sprouting again too soon so keep them cool. Since the Dahlia tubers are resting they need to be kept in the dark. They are living things and it’s all about the balance of moisture, temperature, and light.
The medium you store your tubers in works as an insulation so that your tubers stay a steady temperature and keeps their internal tuber moisture so they don’t shrivel. Some of the most popular “mediums” are vermiculite, peat moss, wood shavings, or newspaper.
Start by putting down a layer of your choice of medium, I’m using peat moss this year, layering your divided tubers in a single flat rows, layer more peat moss on top and carry on to the top of your container making sure the top is a covering layer of peat moss. Put a lid on top or layer 4 or 5 sheets of newspaper on top snuggly.
For the record mice will eat Dahlia tubers that is why I also like putting a lid securely on to keep my Dahlia-tuber-treasures safe. If you live in the wild, wonderful countryside, mice thrive on finding various entryways to your home and outbuildings when cold weather comes. They will chew through things, wood and plastic to get in. Mice, like us, will go to great lengths to locate a gourmet meal without first securing reservations.
When storing your totes, crates or cardboard boxes of peat and tubers do not set them directly on a concrete floor. The concrete will pull moisture out. It’s best to store the totes on shelves, tables or on wood planks on top of the concrete if needed.
Many big Dahlia growers store their totes or crates in big coolers and the temperature doesn’t vary above or below 40 F. thanks to modern electricity. Ideally I feel 45F is ok as well, but getting up to 50F the Dahlias will start stirring after a few weeks and want to send out shoots.
Check your tubers for any signs of rot once a month. A sign of rot is a section that can go soft and also check for mold. One benefit of dividing your Dahlia clumps to individual tubers before storing is that none will be touching each other in storage. That way if one Dahlia tuber shows any negative signs it can be removed and not affect the others.
With just a little effort you are reaping the fruit of your labors, increasing dahlias for this coming season by dividing, then storing away from critters, big and little. I’ll just mention here that raccoons and possums will also eat Dahlia tubers, not just mice. I speak from experience and alarm. So be sure to store those tubers in a cool, safe place not an open barn.
I welcome you to the exciting gardening world of Dahlias. It is a happy place to be and the flowers are fantastic. I will visit more soon. There’s always lots to enjoy when talking about Dahlias.