Fertilize dahlias: How to properly nourish these plants

Fertilize dahlias: How to properly nourish these plants

They are one of the most popular flowers in the garden and on the Balcony. The dahlias have their wedding when some other plants have already withered. From July until well into autumn, they enchant the flora with their magnificent flowers - but only if the plants are properly cared for. This includes fertilizing. The dahlia can be quickly mistreated or even overfertilized.

Your Needs: These Nutrients and Factors Need Dahlia in Nursing

Dahlia is a member of the basketblood family. The original home of these plants can be found in Mexico and Guatemala. It is a perennial bulbous plant that is not hardy. Most dahlia varieties are considered as annual, but there are also tubers of several years. From July until shortly before the frosty winter days, she delights the gardener with her flowers: in the colors white, orange, pink, purple, red and multi-colored combinations. The leaves can score with color plays from dark green to bronze colors.

This flower splendor makes the Dahlia particularly popular in the German gardens. But the optimal care and maintenance of the plants begins with the selection of the right location. Georgines, as the plants are called, prefer humus and nutrient rich soil. The soil in the garden should not be too clayey. Optimally, it has a slightly acidic pH of 6.5. In addition, a bright location is important, dahlias do not thrive well in the shade. Waterlogging also does not like the tubers. Also water on the flowers is undesirable - the gardener should always pour on the ground.

The name Dahlia goes back to the Swedish botanist Anders Dahl. The other name Georgine is due to a mistake. A Berlin botanist named the plant at the end of the 18th century as he thought, "Dahlia & ldquo; be forgiven - yet it meant the same plant.

Which fertilizer for dahlias? Beware of mineral variants in the garden!

Dahlias need the nurturing hand of the gardener both in the garden and in the tub on the balcony and terrace. Nutrients must be added using fertilizer. Here, experts always advise organic fertilizer or whole fertilizer. Although mineral fertilizers provide for increased growth of the plants, but harm the flowering. This means: The dahlia shoots up, but loses its color.

Artificial fertilizer contains too much nitrogen, which promotes the expulsion of dahlia, but also the development of medium-length and thin shoots. Too much foliage is the result. Flowers, however, are hardly developed. And the few buds that the dahlia then shows, can easily turn brown and then rot away. The substance and storability of tubers also suffer from artificial fertilizers.

Therefore, dahlias outdoors should always be supported with organic fertilizer. These include:

  • Cattle manure
  • Pigeon dung
  • Compost
  • Horn shavings

Many a gardener often uses horse manure as fertilizer for the dahlias. This is only partially suitable. Horse manure should only be given if it is well stored. Otherwise, it contains too much ammonia, which can damage the tubers due to its heat.

Especially in the bucket, a permanent care and the supply of dahlia with nutrients are particularly important, because here they are quickly used up in the soil. In contrast to the plants in the garden can be used here also on a commercial liquid fertilizer. This needs the dahlia in the bucket every two to three weeks.

However, the best nutrient supply is already achieved by an addition during planting. So the soil should be mixed with compost. Many a gardener swears by a teaspoon of horn shavings in the planting hole. Others already add flower bulbs when planting. For this fertilizer also protects against vole and promotes rooting through the mycorrhizal fungi.

Frequencies and quantities: So much and so often should you fertilize the dahlia

Dahlias can also be overfertilized. Therefore, the right amount at the right time is as important as choosing the right fertilizer. So it is enough to fertilize the plants outdoors twice a year. The first addition should be at the time of planting the tuber. This gives the Dahlia the right energy injection for the beginning and is rewarded with a strong flowering. A second fertilization should be done in July or August to provide the dahlias with enough nutrients for the final spurt. However, if there is a lot of sand in the soil, even fertilizer application in between can not hurt it.

From the end of August, the gardener should stop fertilizing. Otherwise, the tubers will be overfertilized, which can hurt them very much during wintering. Because most of the dahlia tubers should be dug out the first frost and overwinter in the basement. If they have too many nutrients for this time, they can easily rot. If the tubers are dug out too early, they often have too little nutrients stored to flower vigorously again next spring.

Many a gardener vows to improve the soil in the garden before planting with the basic fertilizer Thomas-Kali. This supplies the soil with phosphorus, potassium, magnesium and important trace elements before the tubers arrive.


Dahlias are popular plants on the balcony and in the garden, as they provide a great variety of colors in late summer and autumn. But only with the right fertilizer does the flower shine. Especially with the tuber plants outdoors should only be helped with an organic fertilizer. Because artificial fertilizer strengthens growth and foliage, but damages the flowering. Dahlias in the bucket, however, need more nutrients. Here you can fall back on a liquid fertilizer.

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