Coffee grounds as fertilizer: uses & benefits

Coffee grounds are a popular home remedy for fertilizing orchids, roses and the like. We show why coffee is good for your plants and how to use it.

Many of us don't really get going without our morning coffee. But have you ever thought that you could also use the coffee grounds to give your plants a boost of energy? We'll show you what's left in your coffee grounds and how it can support us in the garden.

Every German drinks an average of 165 liters of coffee a year - there are plenty of coffee grounds. The coffee grounds are the substance that remains in the filter after coffee has been prepared. There are many different uses for coffee grounds, but most of them just throw it in the trash and miss out on a lot. Coffee grounds can be used to combat pests such as fungus gnats or as a compost additive.

Properties 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. Basically, an average of 2% nitrogen, 0.4% phosphorus and 0.8% potassium remain in the coffee filter.

Since the coffee grounds are slightly acidic (its pH value is around 6.5), it is particularly suitable for plants that prefer acidic soils. These include, for example, citrus plants (Citrus). More about Fertilization of citrus plants such as lemon trees you can find out here.

Benefits of using coffee grounds as a fertilizer

Of course, one of the greatest advantages of coffee grounds as a fertilizer is that it occurs almost by itself in every household and does not have to be bought separately. This saves you the trip to the hardware store and in this way you can reuse a waste product. Coffee grounds are also attractive to earthworms. This is a great advantage, because earthworms loosen the soil and create a crumbly structure of the soil. They also help break down organic matter in the soil.

However, coffee grounds have a repellent effect on pests such as Snails or Ants. These little pests don't like the smell of coffee or the caffeine and will therefore avoid the areas that are fertilized with it.

So the benefits of using coffee grounds as a fertilizer are as follows:

• Occurs in the household
• Is (in principle) free
• Slightly acidic pH
• Attracts earthworms
• Repulsive to snails and ants

For which plants is coffee grounds suitable as a fertilizer?

When using coffee grounds as fertilizer, it is particularly important to ensure that it does not become moldy. So dry the coffee grounds thoroughly. There is a risk of mold in particular with fully automatic coffee machines in which the coffee grounds are collected in a container for a long time. But no matter what kind of coffee machine you have, always dry the coffee grounds before using them as fertilizer to reduce the risk of mold. To do this, simply spread the damp coffee grounds flat - for example on a baking sheet - and let them dry there.

To use it, you should not just sprinkle the dried coffee grounds over the ground, but rather work it into the ground. This allows it to be broken down better and release the nutrients where they are needed. However, you should not overdo it with fertilizing the coffee grounds.

Fertilize garden plants with coffee grounds

In the field you can fertilize with coffee grounds up to four times a year. Over-fertilization with coffee grounds is practically impossible. The best thing to do is to work the substance a little bit into the soil. You can also simply mix the dried coffee grounds with potting soil and place your plants in this soil. All you have to do is mix the contents of a coffee filter (around 30 g of coffee grounds) with the potting soil in a 10 liter sack. That way the earth doesn't become too acidic. You can also simply put the coffee grounds on the compost and let it 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, which help with composting. That way you get an optimal one organic fertilizer.

When it comes to dosing, it is of course an advantage if you try it yourself and start with small amounts at the beginning. The needs of the plants and their sensitivity are often very different.

Fertilize indoor plants with coffee grounds

In the case of indoor plants, it is sufficient to fertilize it once in winter and once in spring. One to two full teaspoons per plant are sufficient for this, which corresponds to about 4 to 8 g of coffee grounds per plant. Be careful, however, because this dose will lower the pH value in the pot and some of our indoor plants could resent this. Don't forget to repot your houseplants regularly afterwards and provide them with fresh substrate.

You can still mix the coffee grounds or leftover coffee with water and water your houseplants with it. To do this, for example, mix old coffee and the irrigation water in a ratio of 1: 1 and use it to water your plants. Make sure not to water the leaves, but simply all around the plant base. You can do the watering and fertilizing in one step.

Coffee grounds as flower fertilizer

When we talk about flowers, we usually mean annual summer flowers. These bloom profusely and usually have a high need for nutrients. Because coffee grounds contain only small amounts of nutrients, fertilizing the flowers with it is not harmful, but it is by no means sufficient. The large amount of organic material and the tannic acids it contains also inhibit the rapid release of the nutrients it contains. Our hungry summer flowers could even slide into malnutrition if they were given too generous coffee grounds.

Nevertheless, the beauties can benefit from the coffee grounds: Together with a strong flower fertilizer - such as ours Plantura organic flower fertilizer - soil organisms convert the hard-to-digest coffee grounds. This can produce valuable humus. This improves the soil properties, which is very useful for the often spoiled summer flowers. To do this, mix coffee grounds and flower fertilizer in a ratio of 3: 1. A good alternative to this process is to compost the coffee grounds along with more nutrient-rich 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 orchid substrate. If your orchids are hydroponically grown, fertilizing with coffee grounds is unfortunately not possible. The coffee grounds are very easy to use with orchids: you distribute the coffee grounds on the surface and then simply water the orchids. Another possibility is to mix some coffee grounds with the earth. Be careful not to use too much coffee grounds, however, as orchids are extremely delicate houseplants. Here you should try it first and see what happens. Just add a small amount of coffee grounds to the orchids and keep an eye on the plant. If the plant finally changes negatively, then you had better stay away from this fertilizer for your orchids. More about the right one Care of orchids find out here.

Coffee grounds as fertilizer for roses

Roses (pink) delight our eyes with their wonderful flowers. But the queen of flowers needs a lot of nutrients, after all, she is one of the heavy 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 work them lightly into the soil. You can do this until the end of June, but after that, roses should no longer be fertilized. You can safely use coffee grounds as an alternative or as a supplement to your usual one Rose fertilization use and then enjoy the great effect. However, there are usually too few nutrients in the coffee grounds to only fertilize your roses with them.

Coffee grounds as fertilizer for hydrangeas

Hydrangeas (Hydrangea) should ideally bloom bushily and abundantly. But this only works if they are properly supplied with nutrients. After all, they place high demands on the floor. Coffee grounds are therefore ideally suited as supplementary fertilization for hydrangeas, because they prefer an acidic soil - coffee grounds are slightly acidic.

It also contains many minerals and optimally supports the hydrangeas in their growth. Coffee grounds alone are not enough to fertilize hydrangeas because the nutrient levels are ultimately too low for that. However, it is an ideal complement to your conventional hydrangea fertilization. Don't just sprinkle the coffee grounds around the hydrangeas on the ground, but work them into the soil so that they can develop their full potential. A thick layer of coffee grounds can quickly form a water-impermeable layer on the surface, which of course is not desirable. If you want to know more about the Fertilizing and caring for hydrangeas you can find more information in our special article.

Coffee grounds as fertilizer for tomatoes

Also tomatoes (Solanum lycopersicum) can be fertilized with coffee grounds. However, they are very consuming vegetables and therefore need a lot of nutrients. Coffee grounds are certainly an effective fertilizer for tomatoes, but unfortunately not enough. You should therefore only use the coffee grounds in addition to an optimal one Tomato fertilizer use. Our Plantura, for example, is suitable for this Organic tomato fertilizer Perfect. This supplies your tomato plants with the necessary nutrients and consists of purely vegetable components. For tomatoes in the pot, however, is the liquid one Plantura organic tomato & vegetable fertilizer better suited, as the incorporation of a granular fertilizer would put the plants under stress.

Coffee grounds as an organic fertilizer supplement

Coffee grounds contain important nutrients and are an ideal fertilizer supplement to provide your plants with nutrients. However, the content of nutrients in the coffee grounds is too low to be able to fertilize with coffee grounds alone. Another possibility is the use of coffee grounds as a supplement to another fertilizer - such as our Plantura Organic fertilizer. This gives you an optimal, well-rounded supply of nutrients in your garden.

More and more hobby gardeners are relying on vegan products in their garden - including fertilizers. Here you can find out everything about the advantages of vegan fertilizers.