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How to dig up dahlias
Published: 12. 11. 2020 · Updated: 12. 11. 2020
While digging up dahlias at the end of the season isn't complicated and you might think it doesn't even need a guide, there are still a few things you need to watch out for.
Dahlias are very sensitive to low temperatures. Areas damaged by frost will turn black, so don't worry, you will recognize it immediately. If there were only light frosts, you might find black spots on the plants here and there. Once hard frosts set in, the whole plant turns black.
When to dig
You can dig up your dahlias, whether they have been hit by frost or not. The only important thing is to dig them up before the ground freezes. However, the ground does not freeze during the first frosts (low temperatures); it takes several weeks. If you let the dahlias be hit by frost, the advantage is that the digging goes quickly, and you don't have to dispose of such a large amount of green matter.
What you will need
Garden fork
You won't need anything special to dig up dahlias, perhaps just a garden fork. Garden forks have 4 tines, so compared to a standard spade, there is a lower risk of damaging the dahlia tuber while 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. Prepare a rinsing area where you can spray the tubers with running water and clear away all the soil.
Inspection
As long as the dahlias still have flowers, we recommend going through all of them and checking if each plant is labeled with the variety name. Once you cut everything back, it becomes a puzzle, and it is impossible to identify which dahlia it is just by looking at the tuber, e.g., its size or shape.
Good weather
We definitely do not recommend digging up dahlias just after it rains when the soil is still saturated. By choosing a suitable day for digging up your dahlias, you will save yourself a lot of work.
Procedure
As a first step, we will get rid of all the green matter above ground so we can even reach the tubers. We trim the stems a few centimeters above the ground. Unless the dahlia is diseased, all the green matter can go into the compost; otherwise, it goes in the bin.
It is important to leave the stems on the plant; they serve as a handle when digging, and most importantly, eyes form around the stem from which the dahlia will grow next year.
After trimming the stems, you can start digging. We have found garden forks to be the best tool for digging. With a spade, you really have to be careful not to damage any of the tubers.
Insert the garden fork about 30 cm from the dahlia stems; the tuber underground can be spread out, so you want to be sure you don't damage anything. Lift with the fork, pull by the stems, and shake off the soil.
The important thing is that the size of the tuber does not matter. Some dahlias form huge tubers, some the tiniest ones. However, it always depends on how many eyes the tuber has—each eye is a plant for next year. A huge tuber might have only one eye, while one you didn't even give a chance of survival might sprout several.
If the soil is dry enough and you can easily clear the soil off the tubers, you have won. If not, they must go under the shower.
If you have clay soil (like we do on our farm) or if the soil is damp and doesn't just shake off, it will be better to rinse the dahlias with a stream of water. If you leave excess soil on the tuber, it can lead to rot in that area after a longer period.
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; that will damage and slice the tubers.
Below, we can see that the tuber already has an eye on the crown. From this eye, the dahlia will grow next year. The tuber will have several such eyes.
Before you start storing the dahlias, they must dry out thoroughly, whether you rinsed them or not. You can put them in room temperature for 3-7 days and then store them. We have described how to store dahlias in another guide, which you can find at /navody/jak-uskladnit-jiriny.
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