Do Coffee Grounds KEEP BUGS AWAY? Yes! It’s Cheap and Eco-Friendly

Last updated on January 15th, 2024 at 06:10 pm

Can coffee grounds keep bugs away?

The answer is YES!

What are coffee grounds?

Coffee grounds are the leftover residue from brewing coffee. They are made up of ground coffee beans, much like flour is made of wheat, and maize is made of corn.

Coffee grounds still contain caffeine, antioxidants, and dietary fiber, though in smaller amounts than before they were brewed.

Ground coffee is used like a tea bag: add hot water to it, let it steep for a few minutes, then strain and drink. The resulting brew is what we all know as the coffee drink.

Coffee grounds can be used around the home and garden for many practical purposes. For example, they can be used as plant fertilizer or scrubbing agents, in skin care products and the coffee grounds keep bugs away if you know how to apply them.

This photo is about a handheld coffee grinder. It sits on a rough timber slate table top and has its lower draw opened that holds coffee beans. in front of the open draw, that are bunch of coffee beans on the table. This handheld coffee grinder looks like a quite old piece. Before the invention of electrical coffee grinder, this is used to be how people grinded their coffee beans to make coffee drinks in the old days. Can coffee grounds keep bugs away? Yes they can, here is why.
An Old Handheld Coffee Grinder

How coffee grounds are made?

Coffee grounds are made from ground coffee beans. The process of making coffee grounds starts with the harvesting of coffee cherries.

The cherries can either be machine harvested or hand-picked following one of two methods: strip picking, where all the cherries are collected off the branches; selective picking, where only the ripe ones are picked.

Once the cherries are picked, the coffee processing phase can be carried out in two ways: the traditional dry method (unwashed or natural) takes longer but is still popular in smaller farms or regions with water scarcity.

The cherries are spread out and left to dry in direct sunlight for 15-20 days, regularly moved and raked, and covered at night until the now brittle outer layer can be removed easily.

The relatively more modern wet method relies on water to move the cherries, which then go through a pulping machine that removes the skin. Afterward, they can either be sun- or machine-dried.

The coffee beans are then hulled by removing their dried husk, polished (for higher quality beans) to remove any leftover silver skin, and sorted and graded based on their size and weight.

The next step is to roast the beans. Roasting is the process of heating green coffee beans to a high temperature to bring out their flavor and aroma. Once the beans are roasted, they are ground into small particles to make coffee grounds.

There are different ways to make coffee grounds at home. One way is to mix water and ground coffee in a saucepan, boil the mixture, stir it with a spoon, let it settle, and then serve or drink it.

Other methods to grind coffee at home include using a blender, mortar, and pestle, or bag and hammer (not very precise).

In a word, coffee grounds are made from coffee beans that have been roasted and ground into small particles.

How do coffee grounds keep bugs away?

How coffee grounds deter pests:

Coffee grounds deter pests because they contain chemicals that harm or kill many insects and animals such as ants, mosquitoes, flies, snails, cats, and deer.

Animals and insects have sensitive noses, which help them stay away from strong smells and things that might harm them.

Coffee smells dangerous to many insects and animals, so they stay away from it. Coffee grounds keep bugs away!

What kinds of chemicals are in coffee grounds that deter pests?

Coffee contains many chemical compounds, but there are two that play a significant role in deterring pests: caffeine and diterpenes.

Caffeine is toxic to animals and insects. If animals or insects take in or are exposed to too much coffee, they could experience higher blood pressure, an irregular heartbeat, muscle spasms loss of muscle control, shaking, and even seizures.

A caffeine overdose kills insects and animals. This is one of the reasons coffee grounds keep bugs away!

Diterpenes occur naturally in plants as a form of self-protection: plants use diterpenes to stop animals and insects from eating them.

Diterpenes are chemical compounds that are designed to disrupt an insect’s hormones so they don’t grow properly.

And diterpenes make animals restless, bloated, and weak, and can even kill them.

That is the second reason that coffee grounds keep bugs away!

What pests do coffee grounds repel?

Coffee grounds can be used on many insects and animals as a pest deterrent. Below is a list of what coffee grounds repel:

How to use coffee grounds as a pest repellent?

To use coffee grounds as a pest repellent, simply sprinkle them onto the soil surrounding your plants or in areas where you want to keep pests away.

You can also use coffee grounds as a natural pesticide by mixing them with water and spraying the mixture onto plants.

Coffee grounds make an eco-friendly and effective pest repellent. Coffee grounds keep bugs away in an eco-friendly way.


In conclusion, coffee grounds are an effective way to keep pests away from your home and garden.

They contain chemicals that harm or kill many insects and animals such as ants, mosquitoes, flies, snails, cats, and deer.

These insects and animals stay away from coffee because they know it’s dangerous.


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