Published: 12. 11. 2020 · Updated: 12. 11. 2020

Even though digging up dahlias at the end of the season isn't complicated and you might think it doesn't need a guide, there are still a few things to watch out for.

Dahlias are very sensitive to low temperatures. Areas affected by frost will turn black, so don't worry, you'll recognize it immediately. If there were only light frosts, you might find black spots here and there on the plants. Once hard frost hits, the entire plant will turn black.

When to dig

You can dig up dahlias whether they have been hit by frost or not. The important thing is just to dig them out of the ground before the soil freezes. That doesn't happen during the first light frosts (low temperatures); it takes several weeks. If you let the dahlias freeze, it has the advantage that the digging goes quickly, and you don't have to deal with such a large amount of green matter.

What we will need

Garden fork

We won't need anything special to dig up the dahlias, perhaps just a garden fork. A garden fork has 4 tines, so compared to a standard shovel, there is less risk that we would damage the dahlia tuber during digging.

Garden hose

If you have heavy (clay) soil and they aren't easy to shake off, you will need to rinse the dahlia tubers under running water. So prepare a rinsing station where you can spray down the tubers and remove all the soil.

Checking

While the dahlias still have flowers, we recommend going through all of them and checking if every plant is labeled with its variety name. Once you cut everything back, it becomes a puzzle, and it's impossible to determine which dahlia it is just by the tuber, e.g., by its size or shape.

Good weather

We certainly do not recommend digging up dahlias right after rain when the soil is still saturated. Choosing a suitable day for digging up dahlias will save you a lot of work.

Procedure

It is important to leave the stems on the plant; they will serve as a handle during digging, and most importantly, the eyes from which the dahlia will grow next year form around the stem.

Insert the garden fork about 30 cm away from the dahlia stems; the tuber underground can be spread out, so make sure you don't damage anything. Lift it with the fork, pull it out by the stems, and shake off the soil.

If you have clay soil (like we do at the farm) or the soil is damp and cannot be easily shaken off, it will be better to rinse the dahlias with a stream of water. If you leave excess soil on the tuber, it could lead to rot in those spots over time.

To rinse the dahlias, a regular garden hose with a nozzle is truly sufficient. The water should have a pressure of 3 - 5 bar; with higher pressure, there is a risk of damaging the dahlia tubers. Therefore, definitely do not use a high-pressure cleaner, as it will disrupt the tubers and cut them in places.

Below we can see that the tuber already has an eye on the root neck. A dahlia will grow from this eye next year. The tuber will have several such eyes.

Before you start storing the dahlias, they must dry properly, regardless of whether you rinsed them or not. You can keep them at room temperature for 3 - 7 days and then store them. How to store dahlias is described in our next guide, which you can find at /navody/jak-uskladnit-jiriny.