Pre-plant dahlias
Hardly any other flower welcomes us as warmly in our summer gardens as the dahlia. This pretty immigrant from Mexico, with its diverse, colorful faces, is worth taking an early interest in its blooms. It's best to start them in pots now!

Warmth preferred
Dahlias are not winter-hardy and therefore frost-sensitive tuberous plants. Strictly speaking, they should only be planted after the Ice Saints in May, i.e., when there is no longer any risk of subsequent frost. Before the winter-dry tubers sprout, you'll need some patience. And when they do, you definitely need to protect them from the voracious slugs that eagerly feast on the tender young greens. You can give the tubers a helping hand with a simple gardening trick. You can start growing dahlias in pots starting in March, on a windowsill, in a cold frame, or in a greenhouse. This also gives the young shoots a head start on the slugs. By the time you plant out the pre-grown dahlias, they will already have reached a size that is no longer so palatable to the slugs, and the blooms can begin earlier.
Into the pot
Place tubers in water for 1-2 hours. Fill empty pots or tubs with fresh potting soil and cover the drainage hole with a piece of clay to prevent clogging and allow water to drain away. Plant the dahlia tuber about 10 centimeters deep. The top of the tuber should be covered with about 3 cm of soil. Water the soil well and then place the pots in a bright, sunny location. Once the tubers sprout, water regularly but sparingly, otherwise there is a risk of waterlogging and rot.

Sun darling
Starting in May, the pre-grown dahlias are planted out into the garden in a sunny spot. Dahlias need plenty of light to bloom profusely. They also love humus-rich but well-drained soil, so add plenty of compost or well-rotted manure to the planting hole. The taller the variety, the more space it needs. The rule of thumb for tall varieties is: one plant per square meter; for shorter varieties, a spacing of 75 cm is sufficient. Mignon dahlias, which usually grow no taller than 30 cm, can be planted even closer together. To prevent these beautiful flowers from being damaged later by heavy rain or wind, it is recommended that the flower heads be supported with a stake for plants 100 cm and taller. Insert a stake or trellis into the soil before planting to prevent damage to the dahlia tubers.

TIP:
If you want to grow dahlias for patio planting, you should find the right pot size right when raising the tubers. Choose a container height that matches the height of the selected variety. The diameter of the planter should be about half the planting height to ensure it remains stable even when the plant is fully grown. In a container, you should provide your dahlias with the necessary nutrients through slow-release fertilizer or regular fertilization with a liquid fertilizer. Whether ornamental, cactus, or pompom dahlias – these colorful Mexican dahlias bloom all summer until the first frost and provide plenty of impressive cut flowers for dreamy bouquets!
TEXT: Martina Raabe