Most dahlias prefer sunny, protected locations with fertilized and well-drained soil. Fertilization and watering are particularly important during the flowering period. How and when you need to fertilize dahlias for abundant flowering can be found in this article.
How to fertilize dahlias?
Fertilize dahlias if possiblewith organic fertilizers, for which mature compost, cattle dung and horn shavings are best suited. Fertilization is carried outat three times: after digging up the tubers in autumn, when planting them in spring and in July before flowering.
When and how often do you fertilize dahlias?
The type of fertilization determines when you fertilize your dahlias. Withorganic fertilizationthe fertilizer is applied at thesethree times:
- in autumn after digging up the tubers
- in spring when planting the dahlia tubers
- before the flowering period begins in July
With mixedorganic-mineral fertilization, provide the plants with an organic fertilizer in autumn and then fertilize between May (from around four weeks after planting) and Augustevery four to six weeksAlternatively, you can also use along-term fertilizer, then the number of fertilizer applications is reduced to two to three. At the end of August, fertilization should be stopped completely.
How do you fertilize dahlias?
In order to optimally fertilize dahlias, you should useorganic fertilizers if possible. These provide the flowers with the right mix of all important nutrients, also improve the soil (and increase the proportion of high-quality humus) and reduce the risk of over-fertilization. And this is how it is fertilized:
- in autumnmature compostorcattle dung fold in at the planting sites
- compost ripens in spring andhorn shavings put in the planting hole
- Quantity: approx. two handfuls per tuber
- fertilize again with compost in July
Alternatively, you can also use ready-made flowering plant fertilizers (€9.00 on Amazon) on an organic basis or granulated cattle manure, for example for dahlias in pots.
Can you fertilize dahlias with coffee grounds?
In fact, you can also fertilize dahliaswith coffee grounds, especially since this natural fertilizer contains plenty ofpotassium- this is important for flowering. However, coffee grounds arenot suitable as the sole fertilizerbecause they do not contain all the nutrients important for dahlia flowers. In addition,coffee acidifies the soil, whereas dahlias need a little lime. There's certainly nothing wrong with a handful of dried coffee grounds every now and then, but only as a supplementary fertilizer. A littlegarden lime, which you apply about four weeks before planting the tubers in spring, helps against a pH value that is too acidic.
How do you fertilize dahlias in a pot?
Dahlias in pots need a little more fertilizer than their planted relatives in the bed. To ensure abundant flowering, you should regularly supply potted dahliasbetween June and Augustwith a liquidfertilizer for flowering plants. These complete fertilizers contain ahigher proportion of phosphorus, which is particularly important for the formation of flowers. You should also use high-quality, compost-based potting soil that is improved with horn meal. Add a tablespoon of horn meal per liter of potting soil. After planting in such nutrient-rich soil, you only start applying fertilizer about four to six weeks later.
Tip
Can you also fertilize dahlias with mineral fertilizers?
In principle, this is possible, but we advise against purely mineral fertilization with blue grain and the like. Mineral fertilizers often contain a lot of nitrogen. Although this stimulates shoot growth, it suppresses the formation of flower buds. In addition, mineral fertilization harms soil he alth and easily leads to over-fertilization.
