A female sitting next to a fire with a dog and a male in the background.

Can Coffee Grounds Prevent Pests?

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Burn Coffee Grounds to Prevent Mosquitoes

Nothing kills the relaxing, outdoor vibe more than those annoying, blood-sucking creatures that come uninvited to concerts, barbecues and camping getaways. While witnessing someone (else) swat around for hours can be entertaining, watching the sunset and enjoying some coffee brownies sounds better than dealing with pesky mosquitoes. 

A male and female sitting around a campfire with two large dogs.

But how can we enjoy the great outdoors when we’re worrying about those little jerks biting our feet, causing allergic reactions (and distress), and carrying a potential virus? Repellents on the market aren’t doing the trick, nor are they doing anything for the spritz of perfume we danced in before heading outside.

What’s the solution? Burn coffee grounds to repel mosquitoes.Besides coffee’s great taste, health benefits and energetic jolt after downing a morning cup of bliss, burning coffee is about to turn into your favorite new hobby.  

The Culprit 

Mosquitoes love standing, stagnant water. Think of all the opportunities your backyard offers to make a breeding ground for mosquitoes. You might have bird feeders, buckets and wheelbarrows, children’s pools, neglected plant pots—all are major sources of the problem areas around your yard.  

The Solution 

Addressing some of the standing water will help you minimize the problem—but likely not obliterate the problem completely. And while store-bought repellents can be expensive—and toxic, looking for a natural alternative to getting rid of those pests makes sense. 

You can control them with coffee grounds, a safe and effective way to keep pests away. Not only do they repel mosquitoes, but also other insects such as wasps and bees. Coffee grounds are the bee’s knees when it comes to staying bug bite free.  

Most bugs have a very strong sense of smell. Coffee grounds are very potent and even more potent once they are burned. The strong scent and “smoldering effect” will fight off pests and keep them away. Additionally, smoke is generally associated with danger, so bugs will look elsewhere for shelter. So, it works, but where do I start? 

How Do You Burn Coffee Grounds?

  • Start with DRY, used coffee grounds. Instead of sacrificing the fresh grounds, you can remove the used grounds right from the coffeemaker and put them in an aluminum foil pie plate or frying pan. Then find a cool, dry area and wait for them to completely dry.
  • Place the grounds in a bowl or on a flat surface outside. Double check that the area is free of animals or children.
  • Burn the grounds like you would incense. You can add just a few drops of lighter fluid to the dried coffee grounds—but be sure not to totally soak them. You don’t want them to burn too quickly. *Adding fresh bay leaves will amplify the results of your repellent! 
  • Choose a spot upwind for best results to get that scent moving!
  • Smoldering, smoking coffee grounds is also an option. If you want to help the coffee grounds smolder, then cover the fire on the plate with a damp towel. The grounds should continue to smoke and smolder.

Reaper’s Pro Tip: 

For some preventative action, water with coffee or used coffee grounds will slow down adult mosquitoes from laying eggs, can kill mosquito larvae—and offer beneficial nitrogen and other nutrients to your garden plants. Unfortunately, it doesn’t always prevent the mosquitoes from generally being in your space. 

How Do You Apply Leftover Coffee Grounds Directly to Plants?  

  1. Collect leftover coffee grounds in a jar for about 25 days. Aged coffee is more effective at killing larvae than fresh coffee. 
  2. Sprinkle coffee grounds around garden plants and trees where water pools. This will help prevent mosquito larvae from taking over. 
  3. For those places around the yard with standing, stagnant water, add 3 tablespoons of coffee grounds per 1 cup of standing water. This will target the larvae. Just don’t add the coffee to ponds or water that animals need to survive. 
  4. Don’t just sprinkle coffee grounds in your yard—it isn’t an effective way to create coffee mosquito repellent. 

We’re all coffee drinkers, here. Unfortunately, drinking the coffee won’t repel the insects—they have to smell the caffeine on and around you. So make sure you have coffee grounds on hand after you finish that favorite brew cup. Doing so will annoy those pests, be good for the wallet, and the best part? It’s all natural.  

RELATED: Your Guide to Watering Plants With Coffee