Winter is approaching here on my south-central Washington farm and there are so many things to consider for the winterizing process. Let's address a few of them.
When to Dig Your Dahlia Tubers
In my climate zone 6A, I need to dig up my tubers to prevent them from freezing. I usually wait until two weeks after the first hard frost before digging them up. However, if the forecast calls for extremely cold temperatures after the frost, I’ll dig them sooner.
How to Dig Your Dahlia Tubers
I have approximately 900 plants, so my methods may differ from yours if you have fewer plants. First, I take a pair of large loppers and cut the stems just above the soil. Then, using a garden fork (see attached picture), I place it about 8-10 inches from the stem and carefully dig down in a circle around it. Gently lift the tubers with the fork, being careful not to break them off in the soil—this is easier in sandy soil than in clay.
Once the ball of tubers is out, I carefully tap it to release as much soil as possible. Make sure to label the tubers by name.
With most of the soil removed, I wash the tubers to remove any remaining dirt. After washing, let them dry for 24-48 hours.
I hope to have a video of this process in a couple of weeks, so check back.
When to Divide Tubers
I divide my tubers in the fall or winter. This allows me to keep track of how many I’ll have for next year and what I can sell. Dividing them also helps save space during storage.
I’ll provide a video showing how to divide tubers soon—stay tuned.
How to Store Tubers
Everyone has their preferred way of storing tubers. A hint: if you read an article where someone says, “This is how I store my tubers” and you're considering changing your method, I recommend testing a small portion first to make sure it works for you.
Here’s what I do: I use bulb crates as my storage containers. Some people prefer smaller plastic storage bins, apple boxes, or Styrofoam fruit boxes from a local grocery store—use what works for you. I line my bulb crates with newsprint to keep the storage medium from falling through the holes. I’ve used peat moss and also tried vermiculite and wrapping tubers in plastic wrap. This year, I’m going back to peat moss since I have a lot of it in storage. I’ll probably switch back to vermiculite next year.
I place a thin layer of peat moss on the newsprint at the bottom of the crate, followed by a layer of tubers, then another layer of peat moss, continuing until the crate is full. I cover the crate with more newsprint and label it with a 4x6 card to identify the Dahlia variety.
The filled crates go into my storage building, which has a heater, humidifier, and fan. I aim to keep the temperature above 40°F and the humidity around 80%. The fan is mounted on the wall to keep the air circulating.
Caring for dahlia tubers through the winter takes some effort, but it’s well worth it to ensure a vibrant garden next year. Whether you’re digging, dividing, or storing your tubers, finding the methods that work best for your climate and space is key. With a bit of planning and care, your dahlias will be ready to bloom beautifully when the warmer months return. Stay tuned for more tips and videos as I continue to share my process!
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