Orchids are one of the most beautiful houseplants of all, which are often given as gifts for various occasions. Especially Phalaenopsis is one of the species that can be found in almost every home. However, it often happens that after flowering, the plants no longer bloom and look lifeless. This can be due to various reasons, but often the right fertilizer can help the orchid to thrive and bloom again. Today we take a closer look at a popular home remedy and explain whether coffee or coffee grounds are good for orchids.
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Ground coffee beans have a reputation for being an excellent addition to your plant fertilizer, but are the benefits the same for orchids? Is coffee grounds really the miracle cure for healthy growth and lush blooms?
What coffee grounds do for plants
Surely, while browsing the internet, you have at least once come across the information that orchids benefit from the addition of coffee grounds. After all, the benefits of coffee for plants are well known – it contains a high concentration of important minerals and trace elements such as nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. These minerals contribute to the healthy growth of many plants by supporting root development and promoting photosynthesis. In addition, the slightly acidic nature of coffee grounds helps improve the physical structure of the soil, increase organic content, improve drainage and create a more favorable environment for some crops. Some, but certainly not all.
Are coffee grounds suitable as fertilizer for orchids?
Coffee grounds are useful for plants, but only for those that live in soil.
For many garden and houseplants, coffee grounds have their purpose and are fine. It is not useful for orchids, and we explain why.
In soil, various beneficial bacteria break down elements and present them in a form that plants can absorb. The goal in using coffee grounds is to get the coffee into a form that can be taken up by plants, essentially the ammonia and nitrate. The easiest way to do this is through nitrifying bacteria (also called nitrifiers, nitrificans or nitric bacteria) that are present in the soil.
But orchids do not live in soil. In short, the bacteria necessary to convert coffee grounds into something the orchid can take up are simply not present in orchid bark (or at least not in sufficient quantity to make a difference). In regular soil, things are a little different.
However, this is the main reason why coffee beans (either fresh beans or ground and brewed) will have no effect on your orchid. The orchid roots simply cannot absorb the coffee in the form it is in and need bacteria or even earthworms to do so. Once the coffee is digested by the earthworms and converted to ammonia and nitrate, the orchid can absorb the nitrogen, potassium, calcium and all the other minerals contained in the coffee. However, since these are not contained in the orchid substrate, the orchid cannot benefit from them.
In its natural form, coffee merely turns the orchid roots brown. Coffee does not make it past the velamen (covering of aerial roots), and even if it did, the roots would not know what to do with it.
Coffee beans can help against pests in orchids
However, coffee is not completely useless in terms of orchid care. The main benefit of coffee beans for orchids is that they repel pests. If you scatter the beans around your orchid display, the strong coffee scent will repel most insects and pests that attack orchids.
In summary about orchids and coffee grounds.
Although coffee and coffee grounds are touted as a miracle cure for many plants, including orchids, its use is not as beneficial as it is claimed to be.
Even as a mulch, adding leftover coffee grounds to your orchid’s pot will not help your orchid because, first, coffee in its natural form without nitrifiers cannot be absorbed by orchid roots and, second, the nitrogen released is caused by the presence of bacteria and earthworms, not the coffee grounds.
The only benefit of adding coffee to your orchid would be that it serves as a pest control agent, although the high concentration of caffeine inhibits plant growth instead of promoting it.
Although coffee beans contain a lot of nitrogen, they are not a suitable fertilizer for orchids because unlike potted houseplants, certain microbes (nitrifiers) must be present in the soil to break down the coffee beans. Since orchids are epiphytes, the microbes around their roots are not the same as in soil. The coffee grounds will remain on the pot and cannot be absorbed by the plant.
If you are looking for a good home remedy to fertilize your orchids after all, you can resort to tea. In this article, we list 3 proven methods of using tea bags as orchid fertilizer.