Coffee grounds are a popular home remedy for fertilizing orchids, roses. We show why coffee is good for your plants and how to use it. Many of us can’t really get on the road without our morning coffee. But have you ever thought that you could use the coffee grounds to give your plants a burst of energy? We will show you what else is in your coffee grounds and how it can support us in the garden.
Every US citizen drinks an average of 685 cups of coffee a year – there is plenty of coffee grounds. The coffee grounds are the substance that remains in the filter after the coffee preparation. There are a wide variety of uses for coffee grounds, but most simply throw it in the trash and thus miss a lot. Coffee grounds can be used to control pests such as mourning mosquitoes or can be used as a compost additive.
Characteristics of coffee grounds
Coffee grounds have many different ingredients that we can use. In addition to nitrogen, phosphorus, and potassium, it also contains tannic acids, antioxidants, and traces of caffeine. In principle, the coffee filter is left with an average of 2% nitrogen, 0.4% phosphorus, and 0.8% potassium.
Since the coffee grounds are slightly acidic (its pH is around 6.5), it is particularly suitable for plants that prefer acidic soils. These include, for example, citrus. Learn more about fertilizing citrus plants such as lemon trees here.
Benefits of coffee grounds as fertilizer
Of course, one of the biggest advantages of coffee grounds as a fertilizer is that it is almost by itself in every household and does not have to be purchased separately. This saves you the way to the hardware store and you can reuse a waste product in this way. Coffee grounds also have an attractive effect on earthworms. This is a great advantage because earthworms loosen up the soil and provide a crumbly structure of the soil. They also help decompose organic materials in the soil.
However, coffee grounds have a repulsive effect on pests such as snails or ants. These small plague spirits cannot suffer the coffee smell and caffeine and will therefore avoid the areas that are fertilized with it.
The advantages of coffee grounds as fertilizer are therefore the following:
- Falls in the household
- Is (principally) free
- Slightly acidic pH
- Attracts earthworms
- Repulsive to snails and ants
For which plants are coffee grounds suitable as fertilizer?
Especially note when using coffee grounds as fertilizer is that it does not become moldy. So dry the coffee grounds thoroughly. There is a risk of mold, especially in the case of coffee machines, where the coffee grounds are collected in a container for a long time. But no matter what coffee machine you own, basically dry the coffee grounds before using them as a fertilizer to reduce the risk of mold. To do this, simply spread out the moist coffee grounds flat – for example on a baking sheet – and let it dry there.
For use, however, you not only sprinkle the dried coffee grounds over the earth but rather work it into the earth. In this way, it can be better decomposed and release the nutrients where they are needed. But don’t overdo it with a coffee grounds fertilization.
Fertilize garden plants with coffee grounds
Outdoors, you can fertilize up to four times a year with coffee grounds. Overfertilization with coffee grounds is practically impossible. It is best to work the substance into the earth a little. You can also simply mix the dried coffee grounds with potting soil and put your plants in this soil. For this, it is enough to mix the contents of a coffee filter (approximately 1.05 oz coffee grounds) with the potting soil in a 2.6 gal bag.
Thus, the earth is not soured too much. You can also simply put the coffee grounds on the compost and let them rot there. There, it has a positive effect on composting and also provides nutrients. This method is extremely effective because the coffee grounds attract earthworms that help with composting. In this way, you get optimal organic fertilizer.
Fertilize houseplants with coffee grounds
For houseplants, it is sufficient to fertilize with them once in winter and once in spring. One to two full teaspoons per plant are sufficient, which corresponds to about 0.14 to 28 oz of coffee grounds per plant. But be careful, because the pH in the pot decreases due to this administration, and some of our houseplants might resent this. Don’t forget to repot your houseplants regularly afterward and provide them with fresh substrate.
You can continue to mix the coffee grounds or leftover coffee with water and pour your houseplants with it. For example, mix old coffee and water in a 1:1 ratio and water your plants. However, be careful not to water the leaves, but simply around the plant base. This allows you to do the watering and fertilization in one step.
Coffee grounds as flower fertilizer
When talking about flowers, one-year-old summer flowers are usually meant. These bloom abundantly and usually have a high nutrient requirement. Because coffee grounds contain only small amounts of nutrients, the fertilization of the flowers is not harmful, but in no case sufficient. A large amount of organic material and the tannic acids contained also inhibit a rapid release of the nutrients contained. For example, our hungry summer flowers could even slip into malnutrition if we have too generous a coffee set.
Nevertheless, the beauties can benefit from the coffee grounds: Together with a strong flower fertilizer soil organisms implement the hard-to-digest coffee grounds. This can produce valuable humus. This improves the soil characteristics, which is very convenient for the often somewhat pampered summer flowers. To do this, mix coffee grounds and flower fertilizer in a ratio of 3:1. A good alternative to this process is composting the coffee grounds together with more nutritious waste. You can then use the compost to fertilize your summer flowers.
Coffee grounds as fertilizer for orchids
The beautiful orchids (Orchidaceae) also benefit from coffee grounds as fertilizer – but only if they are planted in the orchid substrate. Unfortunately, if your orchids grow in a hydroculture, fertilization with coffee grounds is not possible. The coffee grounds are applied to orchids quite simply: they distribute the coffee grounds on the surface and then simply pour the orchids.
Another possibility is to mix some coffee grounds with the earth. Be careful not to use too much coffee grounds, because orchids are extremely sensitive indoor plants. Here you should first try and see what happens. Just add a small number of coffee grounds to the orchids and keep an eye on the plant. If the plant eventually changes negatively, then better leave the fingers of this fertilizer for your orchids. Learn more about the proper care of orchids here.
Coffee grounds as fertilizer for roses
Roses delight our eyes with their wonderful flowers. But the Queen of Flowers needs many nutrients, after all, she is one of the strong-eaters. To give your roses a burst of energy, you can spread about half a cup of coffee grounds around your roses once a month and easily work into the ground. You can do this until the end of June, but after that roses should no longer be fertilized. You can use coffee grounds as an alternative or as a supplement to your usual rose fertilization and then enjoy the great effect. However, the coffee grounds usually contain too little nutrients to fertilize your roses exclusively with it.
Coffee grounds as fertilizer for hydrangeas
Hydrangea should ideally bloom bushy and abundant. However, this only works if they are properly supplied with nutrients. After all, they place high demands on the ground. Therefore, coffee grounds are ideal as complementary fertilization for hydrangeas, because they prefer an acidic soil – coffee grounds are slightly acidic.
Coffee grounds as an organic fertilizer supplement
Coffee grounds contain important nutrients and provide an optimal fertilizer supplement to provide your plants with nutrients. However, the content of nutrients in the coffee grounds is too low to fertilize alone with coffee grounds. Another possibility is the use of coffee grounds as a supplement to another fertilizer. This gives you an optimal, rounded nutrient supply in your garden.
More and more hobby gardeners rely on vegan products in your garden – including fertilizers. Here you can find out all about the advantages of vegan fertilizers.