There are many ways to reuse coffee grounds, and one of the most sustainable is undoubtedly to use coffee as fertilizer for plants. Users, who consider recycling in this way always come to the first question: is coffee good for plants? What are the advantages of using coffee as a plant fertilizer?
In this article, we will try to clarify some aspects of the relationship between coffee and plants, and we will also review some ideas to reuse those coffee grounds or that coffee used for your plants.
Is coffee good for plants?
Plant coffee fertilizer has been used since time immemorial, mainly because it is a natural element and therefore susceptible to mixing with soil nutrients. Its properties are transmitted to the soil, and the plants we grow there can benefit from them. Everything depends on the type of plant and the state of the coffee.
Coffee for fertilizing plants can be used in four main ways:
- Ground coffee for plants (unused).
- Plant coffee grounds (ground coffee but used).
- Liquid coffee (same as the one we drink).
- Manual mixing of coffee with compost.
Advantages of coffee fertilizer for plants
Coffee for fertilizing plants has the following proven benefits for an organic garden or potting soil:
- It’s suitable for your garden friends: worms. But always in small quantities.
- It is terrible for the enemies of your garden: snails, slugs, worms and other invertebrates that can devour your plants.
- Coffee’s natural nutrients and minerals enrich the soil by mixing with it — mainly nitrogen, an essential element for growth.
Ground coffee for plants
Ground coffee as a plant fertilizer is an ideal solution, as it contains all the beneficial properties of plant coffee that we have reviewed before and is also very easy to disperse without creating lumps or thick layers. The only problem lies in the price and unnaturalness of using in your garden a product designed and manufactured for human consumption.
For this reason, it is more practical and sustainable to use the remains of the extractions (or coffee grounds) as fertilizer for your plants.
Coffee grounds for plants
The essential difference between ground coffee and coffee grounds is that the latter has gone through the process of infusion, filtration or processing of coffee. The advantages of using coffee used for plants are mainly two: nitrogen and minerals. Coffee grounds for plants have up to 10% nitrogen – essential for growth – in their composition.
If you manage to collect a large number of coffee grounds, you will have great natural compost for your garden, and you will avoid the need to buy and add conventional fertilizer.
The way to use it is straightforward: pour the coffee grounds around the plants, taking care to always maintain a thin layer (never a too thick layer). If you form a very thick layer of coffee, it could compact and then not let water or nutrients pass to the roots of the plants.
Finally, if you want to make a practical liquid coffee fertilizer, take the coffee grounds and dilute them in water overnight. Then you use it the next day like any other fertilizer: by watering it directly onto the plant. This solution, although more difficult, is less acidic (therefore less aggressive) than using liquid coffee directly.
Generally speaking, coffee grounds are good for plants. Something slightly different from what happens if we use the liquid coffee (as we drink it), and we do not use the excess coffee grounds from the extraction.
Liquid coffee for plants
Is liquid coffee good for all plants? No, it’s not. Some tolerate it, but in others, it can be harmful. We suggest that if you are going to use liquid coffee in the plants, you first inform yourself if your species are going to tolerate it, and of course in case of doubt do nothing.
We can only use liquid coffee on acidophilous plants: that is, those that need acidic soils to grow.
How to use: a small cup of coffee a week is more than enough. If you go too far, the damage can be irreparable.
The big problem with liquid coffee in plants is that the infusion process notably increases their acidity. There is no fixed rule since different types of coffee infusion result in various degrees of acidity. Still, in general, it is always advisable to dilute it in water (the more, the better) if you want to use liquid coffee as fertilizer for your plants.
Making compost with coffee
Finally, another way to use coffee residues to fertilize plants is to use them as a mixture of natural compost. If you already make your compost, you can enrich it by pouring the excess coffee grounds into it. You will enhance its qualities and improve the compost in the same way that you supplement the soil if you pour it directly into the ground.
However, if you use coffee for compost, you must follow a simple rule: coffee should never exceed 20% of the total compost.