NaKu garden tip: use coffee grounds as fertilizer

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

Since coffee grounds are slightly acidic (its pH is around 6,5), they are particularly suitable for plants that prefer acidic soils. These include, for example, hydrangeas, rhododendrons and camellias, but also crops such as citrus plants, cucumbers, tomatoes, zucchini, blueberries and strawberries. The nitrogen contained in coffee grounds ensures strong leaf growth, while phosphorus stimulates flower formation and fruit ripening. Potassium is important for 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

Outdoors, you can fertilize with coffee grounds up to four times a year. Over-fertilization with coffee grounds is practically impossible. It's 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 need to do is mix the contents of a coffee filter (approximately 30 g of coffee grounds) with the potting soil in a 10 liter bag. This way the soil doesn't become too acidic.

The coffee grounds are also used well in the compost. It accelerates rotting, enriches the soil with nutrients and provides food for earthworms. To prevent mold from forming, sprinkle the coffee grounds on the surface and add the filter separately.

Leached potting soil can also be improved with coffee grounds and then reused. To do this, mix equal parts of the old soil with compost 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.