Home generalCoffee grounds as fertilizer - excellent for garden and houseplants

Coffee grounds as fertilizer - excellent for garden and houseplants

  • Ingredients at a glance
    • preparation
  • Coffee grounds as fertilizer in the garden
  • Application for indoor plants
  • Coffee grounds as liquid fertilizer
  • Beneficial side effects

In the ecologically managed garden, coffee grounds as a fertilizer make a valuable contribution to the growth and flowering of ornamental and useful plants. If you have enjoyed your coffee, the remains of the brewed ground coffee are too good for the garbage bin. Read why this is the case and how to properly use coffee grounds as a free nutrient supply for your garden and indoor plants.

After enjoying a fragrant cup of coffee, black granules remain in the filter, which are of great interest to the ecologically-minded gardener. Thanks to an acceptable of nitrogen, potassium, phosphorus and trace elements, coffee grounds are ideal as fertilizer for garden and indoor plants. Do not throw the leftovers in the filter carelessly into the dustbin. Properly prepared, you hold valuable material for nature-related nutrient supply in your hands - and for free. Read here how to use coffee grounds to boost the growth and flowering of your ornamental and crop plants.

Ingredients at a glance

With a per capita coffee consumption of a whopping 6.8 kilograms, in Germany alone we produce 20 million tons of coffee grounds per year. Since every cup of coffee brews, in addition to caffeine, a wealth of health-promoting antioxidants and other ingredients are included, scientists have taken a closer look at what remains of it in the coffee grounds. Antioxidants protect human and plant cells from free radicals and the resulting damage. The findings of the German-Spanish team of competent researchers caused a stir, not least among ecologically oriented gardeners. What remains after brewing in the filter is anything but worthless garbage. The following ingredients could be detected:

  • Nitrogen (N)
  • Potassium (K)
  • Phosphorus (P)
  • Numerous minerals and trace elements
  • Chlorogenic acids (naturally occurring plant substance with effect as radical scavenger)

Some of these nutrients and antioxidants are contained in coffee grounds in concentrations up to seven times as high as in brewed coffee. This raises the relevance of black granules as fertilizer on par with recognized means of nutrient supply in the organic garden.

Tip: Contrary to popular belief, coffee grounds do not acidify the potting soil. With a slightly acidic pH of 6.4 to 6.8, the fertilizer is similar to neutral, such as commercial, mineral-organic flower and plant fertilizers.


Fresh from the filter or portafilter, coffee grounds is not ready for use as a fertilizer. Let the granular material cool down completely. Then spread the fine granules on a plate or a kitchen board. On the sunny windowsill, the material must dry well, so that no mold forms. Then place the dried set in a screw jar or tin to keep it well protected from moisture until used.

Coffee grounds as fertilizer in the garden

At the beginning of the growing season, it is possible to start using coffee grounds as fertilizer. If the soil temperature exceeds the 10 degree mark at night, the microorganisms become active. These have the task of processing the nutrients contained in the fertilizer so that they are available for your garden plants. In particular, earthworms are magically attracted to the granular material and also loosen up the soil wonderfully. How to use the environmentally friendly fertilizer correctly:

  • From March / April to August / September spread dry coffee grounds around the plants on the ground
  • Incorporate the fertilizer superficially
  • Ideally, then mulch foliage, so that the sentence is not washed out by rain immediately
  • In early autumn, stop adding fertilizer so that the plants can ripen before winter

Since each plant species reacts differently to this form of nutrient supply, the best way to approach the optimal dosage step by step. Begin with monthly doses of coffee grounds and shorten the intervals until no improvement in growth and willingness to flower is seen.

Tip: Tea drinkers do not have to do without the useful properties of coffee grounds as a fertilizer for their garden and house plants. Some coffeehouse chains have begun to hand over their coffee grounds on demand for free.

Which plants are primarily considered ">

In ornamental and vegetable gardens, coffee grounds have a particularly vitalizing effect on plants that prefer slightly acidic to neutral conditions. The best results are achieved with rhododendrons, roses, hydrangeas, geraniums, cucumbers, tomatoes, berries and pumpkins.

In contrast, lime-loving garden plants react either not at all or adversely on coffee grounds as fertilizer. These include: carnations, lavender, phlox, strawberries, carrots, honeysuckle, sweet cherries and most bulbous flowers.

Application for indoor plants

Most houseplants love a slightly sour to neutral substrate, so coffee grounds are especially welcome as fertilizer. The following options for a useful application are available:

  • Mix a handful of coffee grounds under fresh potting soil to plant the plants in it
  • with existing houseplants spread the fertilizer thinly on the substrate and work in easily
  • Alternatively, mix the dry set with some humus to replace the upper 2 cm of the previous potting soil

In view of the comparatively limited substrate volume of indoor plants, we recommend a careful approach to the dosage. Gain step-by-step experience of how your flower and petal plants respond to unorthodox nutrient delivery. As a rule of thumb, coffee grounds as a fertilizer is administered only during the growth and flowering period. Are your houseplants in the winter or artbedingten resting phase, is not fertilized.

Coffee grounds as liquid fertilizer

If garden plants are flourishing in the tub, the supply of liquid fertilizer is more practicable as a solid fertilizer laboriously incorporated into the substrate. The same applies to your houseplants in a flowerpot. To do this, dissolve a small amount of coffee in the irrigation water by placing 1-2 tablespoons in a 10-liter watering can and stirring until the granules have dissolved. Please add the enriched irrigation water directly to the potting soil from the potting tube, without moistening any leaves, shoots or flowers.

Beneficial side effects

Coffee grounds not only provide your garden plants with important nutrients, but also exert pleasing effects. In what respect the black granules still come to honor in your green kingdom, we have put together for you in the following overview:

  • Coffee grounds have a toxic effect on snails by spreading the soil on endangered plants
  • Ants avoid areas that smell like coffee
  • Filled in a fireproof bowl and lit, aggressive wasps go ahead
  • Beds interspersed with the set are not misused by cats as litter boxes
  • Scattered as a liner on the compost, the rotting progresses more quickly

Last but not least, diligent gardener hands can be perfectly cleaned with a mix of coffee grounds and soap. Deposits in flower pots or vases are removed with the granular granules in an instant, without having to resort to chemical agents. Simply pour 2 tablespoons of coffee grounds into the container, pour hot water over it, shake well and let it steep for 1 to 2 hours. Spreading your work shoes after sweaty gardening an unpleasant smell, coffee grounds provides a remedy. Sprinkle a handful of the powder in your shoes and leave it overnight. The next day the shoes knock out and you can go back to work without any odor nuisance.

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