Harvesting dahlia tubers

We just finished harvesting our dahlias! Every fall, it's a task we dread a little. Mentally daunting and physically demanding, we have thousands of them to dig up, transport, wash, divide, and then store. So, we're motivating ourselves as a group. We wait for beautiful, warm, sunny days to complete the task, put on some good music to get us through it, and happily begin the work!

The process remains very simple, whether on a small or large scale. It's only the quantity of plants to be dug up that proportionally increases the scale of the mission.

We explain our method to you, as always, in the simplest and most effective way possible.

Why dig up dahlias in Quebec?

Quebec's climate is characterized by harsh winters, with temperatures that drop well below zero, making it impossible for dahlia tubers, which are native to Mexico, to survive. Therefore, exposing the tubers to freezing temperatures should be avoided at all costs.

When to dig up dahlias?

There are two options:

1- After 120 days of cultivation

If you're in a hurry and want to remove your dahlias before the first frost, you can dig them up after about 120 days of cultivation (about four months after planting). This time allows the tubers to develop and build up the reserves needed to survive the winter. At this point, even without frost, the tubers are mature and ready for harvesting and winter storage.

2- After a ground frost

Most gardeners choose to dig up dahlias after the first frost to enjoy their blooms for as long as possible. Dahlias naturally go dormant with the drop in light and temperatures in the fall, which slows their vital activity. An initial frost kills the foliage by blackening and wilting it, indicating that the dahlia has completed its annual cycle. Although the leaves may still appear somewhat alive after an initial light frost, a heavier frost kills them completely, signaling that it is the right time to dig up the tubers. Note that the danger of losing dahlias lies in frost on the tubers, not frost on the above-ground parts of the plant (leaves and trunk). The tubers are buried 6" underground and a few light frosts on the ground are not strong enough to freeze the soil deep down and reach the tubers. However, if you dig up the tubers on a day when it is -5, there is a risk of freezing when digging up and handling the tubers in the ambient air!

Steps to Dig Up Dahlias:

1. Cut the stems
   Use large pruning shears to cut the dahlia stems about 10-15 cm from the ground. This will make extraction easier and prevent you from losing the location of your tubers!
   
   
2. Gently remove the tubers
   Push your fork about ten centimeters from the base to avoid damaging the tubers. Carefully dislodge them by lifting them from the ground. Caution: the tubers are fragile and break easily.
   
   
3. Shake and clean
   Once the tubers are out of the ground, take the stem and shake them lightly to remove excess soil.
   
   
4. Wash them, or not
   We prefer to wash the tubers because it makes division easier by exposing the crown, the area where the "eyes" are. Washing them also makes them lighter, which is important when you have thousands of them to move! It is also possible not to wash them and leave them as is, a little earthy, for the storage period if that is what is most convenient for you.
5. Divide the tubers now, or not!
   Dahlias can be divided for propagation and long-term sustainability. Division can be done in the fall or spring, depending on the time available for the task. It's worth noting that the storage space required for undivided tubers is much greater than the storage space required for divided tubers. (A blog post on storage and another on dividing dahlias will be coming soon!)

Although demanding, this process becomes easier and more enjoyable when you're well prepared, organized, and work in a positive atmosphere. Digging up dahlias at the right time and following the steps carefully ensures healthy tubers and vibrant blooms for the following season.

Whether you're a gardener with a few plants or a florist with thousands of tubers, the important thing is to adapt your method to your needs and resources. Stay tuned for our upcoming articles to learn everything you need to know about storing and dividing dahlias!