Without a doubt, dahlias are one of the most beautiful ornamental plants ever: The daisy family is available in an almost unmanageable variety of colors, shapes and sizes and blooms for months. However, the flowers are not hardy, which is why the tubers have to be dug up in autumn.
When and how should you dig up dahlias?
Dahlia tubers should be dug up in late fall, after the first frost. First, cut off the dried foliage, leaving stems just above the bulbs. Then carefully dig up the tubers and let them air dry with clods of earth.
Can you leave dahlia tubers in the ground in winter?
In fact, you have to dig up the dahlia tubers in the fall because the plant, which originally comes from warm Mexico, is not hardy. Quite the opposite: the tubers are very sensitive to frost and would die in a cold winter.
Only in regions with mild winters - for example in the wine-growing climate of the Upper Rhine Graben - can you try to leave the tubers in the ground over the winter months. As long as there is no ground frost, they should survive in these conditions. Dahlia tubers can also survive outdoors in other regions, as many forgotten and sprouted tubers have proven - but there is no guarantee for this.
When should dahlias be dug up?
The right time to dig up dahlias is late autumn. However, leave the tubers outdoors until the first frost so that they ripen. Keep an eye on the weather forecast so you can get the tubers out of the ground on time. Basically, dahlias should stay outside as long as possible and only be brought in when there is no other option.
It's easier if you cultivate dahlias in a pot: you don't have to dig up the bulbs, you just need to bring the plant pot into the house.
How are the dahlia tubers dug up?
Before you dig up the dahlia tubers, first cut off the (dried) leaves, although the stems may only be cut off just hand-high above the tubers. This stem remnant must be preserved because otherwise the shoot buds sitting close beneath it will dry out. After cutting, dig up the tubers carefully, for example with a digging fork (€139.00 on Amazon) and then let them air dry with the clods of earth - of course not outdoors.
How are the dahlia tubers stored?
Store the dug up dahlia tubers in a cellar that is as cool as possible but frost-free. If you don't have a suitable cellar, the tubers can also be overwintered in other places that meet these conditions.
It is best to store the tubers in wooden boxes and wrapped in moist sand. In warm basements you need to moisten the substrate from time to time. The tubers must not rot or dry out, otherwise they will not sprout again in spring.
Tip
When to take dahlias out of winter quarters?
In spring you can take the tubers out of their winter quarters and plant them in April - provided the weather is mild and the ground is frost-free. In this case, you don't have to worry about late frosts, as you can also cover the planting area with fleece or something similar. Before planting, you can divide the tubers and multiply them.
