As you spend time outside enjoying a beautiful day, nothing cramps your style quite like being bombarded by mosquitoes. While there are plenty of commercial products that keep mosquitoes at bay, there’s a growing interest in natural alternatives.
One that’s picking up steam — burn coffee grounds to repel (but not kill) mosquitoes.
But does it work?
According to many people, it does — though scientific research on the method is limited.
This guide takes a closer look at whether coffee grounds keep mosquitoes away, how to properly prepare the grounds, how to safely burn them, and how to ensure this method is as successful as possible.
Burning Coffee Grounds As a Mosquito Repellant: The Evidence
Research is limited, but some findings suggest coffee grounds may help deter mosquitoes.
Burning them creates smoke, which studies show is effective at reducing mosquito activity in general [2].
Just as with people, thick smoke makes it harder for insects to breathe and fly.
Coffee itself may add extra protection. Caffeine has been shown to lower mosquito larval survival and shorten adult lifespan [3], while diterpenes in coffee act as natural pest deterrents [4].
However, for these compounds to work, insects need direct contact with the grounds — which makes them more effective against crawling pests like ants than flying mosquitoes.
Beyond lab results, there’s also anecdotal support: many campers and homeowners report success using burned or scattered coffee grounds to keep bugs at bay [1].
Still, the scientific evidence remains sparse, so this method should be seen as a low-cost experiment rather than a guaranteed solution.
Expert & Professional Insight
In addition to the scientific and anecdotal evidence, experts like Entomologists and pest control professionals have also spoken about this method at times.
For example, research published in the Journal of Medical Entomology found that caffeine had an impact on the blood-feeding behavior and survival of mosquitoes. [5]
How to Effectively Burn Coffee Grounds as a Mosquito Repellent
Before you rush to burn coffee grounds to get rid of mosquitoes, make sure you’re doing it safely.
Use the following steps to safely and efficiently burn coffee grounds:
Step 1: Prepare Your Coffee
Start with pre-ground coffee or use whole bean and grind it yourself
If you have old coffee grounds saved, you can use them, as well. If you use old coffee grounds, dry them completely before burning.
If you don’t dry them enough, they may not catch fire well and may not burn efficiently even if they do catch fire.
Step 2: Choose Your Burn Container
You can choose from commercial burners, metal cans, tinfoil, bowls, or even plates. Whatever you choose, make sure your burning surface can take plenty of heat. Also, you shouldn’t use a container you don’t want to see get damaged, as burning the grounds may stain the bowl and leave it discolored.
Step 3: Add the Grounds to the Container
Form a small mound, around an inch and a half to two inches. Next, make a small divot in the mound and either add in a wick or a small bit of lighter fluid.
Step 4: Move the Container(s) to the Burn Location
This should be outside — the exact spot depends on where you don’t want mosquitoes. You can place the containers near your home, beside your patio, by the garden, or anywhere else. However, if you have children or pets, keep the grounds away from them, such as on a table or other elevated surface.
Also, consider the wind; make sure it’s blowing in the direction you want it to, and not into an area you don’t (such as your house).
Step 5: Light the Grounds
Soon they’ll begin to smolder and smoke will bellow out just like an incense burner.
Step 6: Check the Grounds Often
Check to see if they’re still going, or if they need to be relit. Never leave the burning grounds unattended.
Step 7: Put the Grounds out by Smothering them with a Damp Towel
While they’ll eventually go out on their own, this method is suitable for stopping the burning immediately if you need to.
Alternative Natural Mosquito Repellent Methods
Coffee grounds aren’t your only option. Here are a few other natural methods that can help you keep mosquitoes at bay:
1. Citronella
Citronella is one of the most well-known natural repellents. Studies show it’s highly effective and even rivals synthetic options when used properly [6]. It’s commonly found in candles, sprays, and oils.
2. Neem Oil
Neem oil is another plant-based repellent that works against a wide range of mosquito species [7]. It can be applied to the skin when diluted or used in oil burners.
3. Environmental Changes
Controlling your surroundings is just as important as what you apply to your skin. A few effective strategies include:
- Eliminating standing water (bird baths, plant saucers, etc.)
- Trimming tall grass and overgrown plants
- Installing window and door screens
- Attracting natural predators like dragonflies, birds, and bats
Together, these changes can drastically reduce mosquito populations around your home.
When to Call in the Pros
If your mosquito problem is overwhelming despite your best efforts, it might be time to call in professional pest control.
Large infestations may require more targeted treatments than DIY methods can offer.
FAQs: Coffee Grounds & Mosquito Control
If you’re still curious about using burnt coffee grounds for mosquito control, check out these FAQs to learn more.
1. Does Burning Coffee Grounds Actually Repel Mosquitoes?
Yes, burning coffee grounds can be effective in repelling mosquitoes. This is largely due to them being sensitive to the smoke from the burning grounds, but they also may find the pungent odor unpleasant. Also, the burning coffee grounds may mask some of the scents that attract mosquitoes to humans, as well.
2. How Do I Effectively Burn Coffee Grounds to Repel Mosquitoes?
The process includes drying the grounds, choosing a safe burning surface (such as an old bowl, a plate, a metal tray, or aluminum foil), finding the proper location, and then lighting them. Choose a location that’s away from pets and children, won’t blow smoke through your doors or windows, and is close to where the mosquitoes are being the most problematic.
3. How Long Does Burning Coffee Grounds Repel Mosquitoes?
Burning coffee grounds can often repel mosquitoes for a few hours. However, the exact duration depends on how much grounds you burn (and how many containers you use), how ventilated the area is, and how much wind there is. For continuous protection, you may need to replace the burnt coffee grounds every couple of hours.
4. Is Burning Coffee Grounds Toxic for Humans & Pets?
Burning coffee grounds may potentially be hazardous and harmful for both humans and pets, especially for children and those with respiratory conditions. To safely burn coffee grounds and minimize safety risks, do it in a well-ventilated area or outside, and use proper precautions when burning to eliminate the chances of starting a house or yard fire.
5. How Does Burning Coffee Grounds Compare to Commercial Mosquito Repellents?
Burning coffee grounds works for repelling mosquitoes, but it isn’t quite as effective or long-lasting as commercial mosquito repellents like DEET. Commercial products are better when you need long-term protection; however, coffee grounds are readily available, budget-friendly, and awesome for camping or other situations when you only need short-term protection.
6. What Other Insects Do Coffee Grounds Repel Besides Mosquitoes?
In addition to mosquitoes, coffee grounds can also repel snails, ants, spiders, fruit flies, and other pests. They also may be effective against slugs and certain beetles, though the results may vary on a case-by-case basis.
7. Can Coffee Ground Smoke Stain Outdoor Furniture or Surfaces?
Yes, coffee grounds may stain outdoor furniture or surfaces, especially if they’re lighter in color or porous. As a result, consider covering the furniture or surfaces to protect them, and if staining occurs, use a cleaning solution made of mild dish soap and warm water to try and clean the area.
8. What Can I Combine with Coffee Grounds for Better Results?
Boost the mosquito-repelling efforts with chili, pine, lavender, citrus, or mint, as these are scents mosquitoes generally don’t like. Many of these are quite pungent, so you shouldn’t need to add much to the mixture for them to be effective.
9. What are the Best Alternatives if Burning Coffee Grounds Doesn't Work?
If burning coffee grounds doesn’t help, other natural repellent methods include essential oils, citronella, and certain plants like lemongrass and marigolds. You can also manage your environment to become less mosquito-friendly by eliminating standing water, using screens, or encouraging the presence of natural mosquito predators.
10. Can Used Coffee Grounds Work as a Mosquito Repellent Without Burning Them?
Yes, while burning coffee grounds may be an effective mosquito repellent, you can also simply spread them around your garden or create a barrier around somewhere that you don’t mosquitoes to go. However, while these other methods may be effective, burning the grounds is generally the most effective option, as it creates the most pungent and fragrant odor.
References
- Satho, T., Dieng, H., Ahmad, M. H. I., Ellias, S. B., Hassan, A. A., Abang, F., Ghani, I. A., Miake, F., Ahmad, H., Fukumitsu, Y., Zuharah, W. F., Majid, A. H. A., Kassim, N. F. A., Hashim, N. A., Ajibola, O. O., Al-Khayyat, F. A., & Nolasco-Hipolito, C. (2015). Coffee and its waste repel gravid Aedes albopictus females and inhibit the development of their embryos. Parasites & Vectors, 8(1).
- Meer, R. (2022). Smoke as a form of personal protection against mosquitoes, a field study in Papua New Guinea. The Southeast Asian Journal of Tropical Medicine and Public Health, 25(4).
- Miranda, F. R., Fernandes, K. M., Bernardes, R. C., & Martins, G. F. (2021). Biological, histological, and immunohistochemical studies on the toxicity of spent coffee grounds and caffeine on the larvae of Aedes aegypti (Diptera: Culicidae). Environmental Pollution, 271, 116307.
- Antoine, G., Virginie Vaissayre, Meile, J.-C., Payet, J., Geneviève Conéjéro, Laurent Costet, Fock-Bastide, I., Thierry Joët, & Stéphane Dussert. (2023). Diterpenes of Coffea seeds show antifungal and anti-insect activities and are transferred from the endosperm to the seedling after germination. Plant Physiology and Biochemistry, 194, 627–637.
- Abernathy, H. A., Boyce, R. M., & Reiskind, M. H. (2023). Exploring the effects of caffeine on Aedes albopictus (Diptera: Culicidae) survival and fecundity. Journal of Medical Entomology, 60(4), 837–841.
- Iovinella, I., Caputo, B., Cobre, P., Manica, M., Mandoli, A., & Dani, F. R. (2022). Advances in mosquito repellents: effectiveness of citronellal derivatives in laboratory and field trials. Pest Management Science, 78(12), 5106–5112.
- Sharma, S. K., Dua, V. K., & Sharma, V. P. (1995). Field studies on the mosquito repellent action of neem oil. The Southeast Asian Journal of Tropical Medicine and Public Health, 26(1), 180–182.
