The Content Of The Article:
- The ideal varieties for the pot
- The right planting time
- When planting early, select small pots
- Pinching young shoots
- Lots of sun, water and nutrients
- Hibernation of pot dahlias
Dahlias bloom non-stop from the end of June to the first frost. The frost-sensitive tuber plants from Central America are therefore extremely popular as bedding plants. The long flowering period and its robust nature are also excellent conditions for a successful potted plants career. The culture of dahlia in large planters is not rocket science - if you know the preferences of the colorful exotics.
The ideal varieties for the pot
For the culture in the pot are best suited to small to medium-sized dahlia varieties, for example mignon dahlias and cervical dahlias. Even weakly growing varieties of the water lily dahlias as well as ball and pompon dahlias are excellently suitable for container planting. Many varieties of stately cactus dahlias, on the other hand, can grow over two meters high and are therefore not the best choice for planters. They have a high water requirement and therefore need a voluminous vessel. In addition, the planter must not be too light, so it does not tip over in gusts of wind. As a rule of thumb, therefore, one should only plant dahlia varieties in vessels that manage in the bed without support pile.
The right planting time
If you can not provide your pot dahlias with bright, frost-free quarters until the outdoor season, you should not plant the tubers before the end of April. On the other hand, if an unheated greenhouse or conservatory is available, there is nothing wrong with a previous planting date around the first of April. Of course, early-flowering tubers flower earlier, but they must be thoroughly hardened before being placed on the balcony or terrace after the icy saints. This also applies to dahlias, which were already propagated in early spring on shoot cuttings from propagated tubers.
When planting early, select small pots
For early planting and temporary greenhouse culture, you should first put the tubers in small pots for space reasons. The planting depth corresponds to the outdoor planting - the shoot buds on the tuber shafts should be only slightly covered with soil. As a substrate, you can use normal balcony potting soil, which should be very permeable. It has been proven to mix some sand and clay granules. Because dahlias are also very nutrient-needy, you can add per liter pot earth as nitrogen supply still a heaped tablespoon horn meal.
Place the dahlia tubers in the middle of the pot as flat as possible (left) and then pour well (right)
Preferred dahlias are transplanted into larger buckets shortly before the start of the outdoor season. Depending on the vigor of the variety, the planters should have a diameter of 25 to 50 centimeters. Place the small pot bales so deep in the ground that their surface is covered only slightly with fresh soil.
Pinching young shoots
If the first shoots are about ten inches long, you should remove the shoot tips with fingernails or scissors. This so-called Pinzieren causes the dahlias to branch well and grow compact and bushy from the beginning.
Lots of sun, water and nutrients
For dahlias to blossom and thrive, they need a sunny and sheltered location on the terrace or balcony. Due to their large, soft leaves, the tuber plants have a high water requirement - daily watering is therefore mandatory. On very hot sunny days, the plants often leave the leaves hanging in the late afternoon despite abundant watering and should then be watered again. For nutrient supply, a phosphate-rich liquid balcony flower fertilizer is suitable. It is given once a week with the irrigation water.
Pot Dahlias 'Arabian Mystery' (left) and 'Pretty Woman' (right)
In order for dahlias to continuously form new flower shoots, you should cut off the withered stems each over a well-developed pair of leaves. As a result, new flower stalks drift in the leaf axils within a few weeks.
Hibernation of pot dahlias
When the first frosts threaten, pot dahlias, like their relatives in the field, are cut off near the ground and winterized frost-free. If you have enough space in the winter quarters, you can overwinter the tubers in the planter. Otherwise, it is recommended to remove the pot soil and to overwinter the tubers like free-range dahlias "naked" in boxes with sand or loose, dry potting soil. In the next year, the tubers have to be put into new soil anyway, since the old one is then mostly exhausted and no longer structurally stable.