NaKu garden tip: use coffee grounds as fertilizer

Today there is a garden tip. 7,2 kilograms of coffee per capita are consumed annually in Germany, in Austria it is 7,8 kilograms. Quite a lot of coffee grounds end up in the garbage. However, it can be used as a fertilizer in the garden because it contains a lot of valuable ingredients such as potassium, nitrogen, phosphorus, tannic acid and antioxidants. These are nutrients that are also found in commercial fertilizer products. The basic requirement for use is that it is always well cooled and dry, as moist coffee grounds easily mold. To do this, place the coffee grounds in an open, wide container and allow them to air dry.

Since the coffee grounds are slightly acidic (its pH is around 6,5), they are particularly suitable for plants that prefer acidic soil. These include, for example, hydrangeas, rhododendrons and camellias, but also useful plants such as citrus plants, cucumbers, tomatoes, courgettes, blueberries or strawberries. The nitrogen contained in the coffee grounds ensures strong leaf growth, while phosphorus stimulates flowering and fruit ripening. Potassium is important for the cell structure and the stability of the plant. Only seedlings do not tolerate caffeine well. As a fertilizer, simply work the coffee grounds into the soil, for example with a rake.

Coffee grounds also have a repellent effect on pests like snails. These little pests don't like the smell of coffee or caffeine and therefore avoid the areas that are fertilized with it. However, this is not the case for all species. But it's definitely worth a try.

Fertilize garden plants with coffee grounds

In the field you can fertilize up to four times a year with coffee grounds. Over-fertilization with coffee grounds is practically impossible. It is best to simply work the substance into the soil a little. You can also simply mix the dried coffee grounds with potting soil and plant your plants in this soil. All you have to do is mix the contents of a coffee filter (about 30 g of coffee grounds) with the potting soil in a 10-litre bag. That way the soil doesn't get too acidic.

Coffee grounds can also be put to good use in the compost. It accelerates decomposition, enriches the soil with nutrients and provides food for earthworms. To prevent mold from forming, sprinkle the coffee grounds on the surface, put the filter in separately.

Exhausted potting soil can also be improved with coffee grounds and then reused. To do this, mix the old soil with compost in equal parts and fold in the coffee grounds in small quantities. However, if there is too much coffee in the soil, mold can easily form.

Fertilize houseplants with coffee grounds

For indoor plants, it is sufficient to fertilize once in winter and once in spring. One to two full teaspoons per plant are sufficient for this. Be careful, though, as this will lower the pH in the pot and some of our houseplants may take offense. However, old coffee mixed with water in a ratio of 1:1 is more suitable. This allows you to water and fertilize in one step.