Will Coffee Grounds Kill Ants & Repel Insects? We Tested!

No matter where we live, we’ve all spotted an unwelcome insect of one species or another invading our homes.

Although most of us may have the instinct to smash said insects under our shoe, or whatever tool is closest at the time, there might be an easy solution to repelling them before they enter our domain.

Coffee grounds are an extremely potent substance for different species of insects making it a perfect solution to use as a natural repellent for your home. Not only is coffee a great deterrent for many common pests, but it’s also especially useful when defending your home or food from ants!

Before you attempt to sprinkle coffee grounds over everything in your house, first learn what insects are repelled the most.

Here are some tips and tricks for making the coffee ground repellent method work better and where the best places are to sprinkle this magic solution.


What Insects do Coffee Grounds Repel?

In general, some insects are repelled by coffee grounds like ants, mosquitos, and more. However, it’s essential to keep in mind that some are attracted to them. One such pest is the roach. Keep this in mind depending on where you live and what may be lurking before attempting this natural solution.

What Insects are Repelled by Coffee Grounds?

  • Ants
  • Mosquitos
  • Wasps
  • Bees
  • Snails & slugs
  • Fleas
  • Earwigs
  • Spiders
  • Gnats
  • Beetles

What Insects are Attracted to Coffee Grounds?

  • Cockroaches
  • Fruit flies
  • Worms

Will Coffee Grounds Kill Ants?

Photo by Tyler Nix on Unsplash

Overall, laying out coffee grounds will not kill ants, however, it’s a great tool to repel them. Many insects are susceptible to odors as this is a means for navigation. Additionally, coffee compounds like caffeine are believed to be contributing deterrents as they can be highly toxic to insects.

It has been tested that pouring boiling hot coffee down an actual anthill has been known to kill many of the ants. However, it’s believed that the boiling factor plays a bigger role in that victory than the actual coffee itself.

Regardless, studies show that coffee can be used as an effective repellent. Another study shows how compounds in coffee emulsions can prove to be a successful pest eliminator. The integration of coffee in the boiling method helps with the after effect of deterring any residual survivors from repopulating colonies in the area.

Top 6 Methods to Get Rid of Ants & Insects with Coffee Grounds

There are various methods to keep ants and other pests away from your kitchen, home, and the garden. Coffee ground methods are natural, easy to prepare, and effortless to execute. It must be noted that used, soaked coffee grounds are more effective than unused, fresh grounds.

1. Lay Out Coffee Grounds

Used coffee grounds have a strong odor and can be laid out in small plant pots and containers to keep pests away. This is a better option for outdoor ant control versus inside the home as random bowls of coffee may attract small children, can clutter space, and can be the cause of accidental messes.

Unlike hosting a coffee party for friends, simply offer a cup of used coffee grounds to pests. You can lay out bowls of used coffee grounds around garage, back, and porch doors, the patio, and other outside areas to keep ants, mosquitos, bugs, and wasps away.

2. Sprinkle Coffee Grounds

In total, the simplest way to disperse coffee grounds as a natural repellent for insects and bugs is to sprinkle them around in the affected area. This is a great option for outside problem areas like backyards with anthills.

Simply sprinkle grounds right into the ant hill and surrounding areas. You can also sprinkle coffee grounds along garden edges, where the patio meets the grass, and where known ant trails lead to doors and windows.

Pro Tip: For infestations, place a heap of soaked coffee grounds directly into the ant mound. To beat it fast, it’s best to go big and heavy handed.

While this method will not kill ants, it does disrupt their scent trails. Some ants will prove to be more opportunistic than others and will carry off grinds to their food storage hoards. Add a spritz of vinegar or lemon juice to the grounds every few days to further enhance your repellent efforts.

3. Use Coffee Grounds in a Garden

Coffee grounds can be harmful for many plants. The acidity can cause a weakened state that may inadvertently attract pests. Rather than sprinkling coffee grounds directly to the soil, create a mix with compost to keep ants, earwigs, slugs, and snails away from your garden beds.

You will want to research what plants, flowers, and vegetables do well with coffee grounds. The acidity in coffee can make for a mulch that do well with it such as azaleas, hydrangeas, carrots, and radishes. Try layering coffee grounds, grass clippings, leaves, or bark mulch. You can add small amounts directly to the soil and make sure to lightly rake it for even distribution.

4. Age the Coffee Grounds

Aging coffee grounds simply means to let it sit in a jar for at least 25 days. It’s said to be stronger in killing off pests like mosquitoes and their larvae. The odor also deters other pests like ants and spiders.

Aged coffee grinds can be applied directly to areas where there is standing and stagnant water. You can also use 3 Tbsp of coffee to 1 cup of water in vessels around the home to keep the mosquito population and their larvae at bay.

5. Burn Coffee Grounds

Overall, the odor of burning coffee grounds is a warning signal to mosquitos and other insects to stay away. This is an outdoor method and is not safe for indoor pest control.

Simply allow the used grounds to completely dry out. Distribute grinds to foil plates such as aluminum foil pie plates. Apply to a small amount of lighter fluid and light. Dampen out the flames with a large cloth but allow the grounds to continue smoldering.

Pro Tip: Add bay leaves to the coffee ground fire to boost its repellent effects!

You will need to ensure this method is being done in a controlled environment, no small children are around, and you have fire extinguisher devices or a water supply ready for emergencies.

6. Add Other Elements

To kill or further enhance your repellent efforts, add other elements or ingredients to your soaked coffee grounds for a stronger, potent, and odorous solution. Ingredients such as lemon juice, peppermint oil, cinnamon oil, and vinegar can intensify the repellent effects.

Other products that are can be mixed with coffee grounds include Borax, dish soap, crushed red pepper, baking soda, baby powder (talcum powder), and sugar. These can be used together, alone, in water spray solutions as DIY ant killers and deterrents.

How to Use Coffee Grounds as Insect Repellent? We Tested!

Test #1: Burning Coffee Grounds

As a general rule, coffee grounds are even more potent to insects when it is burned, as this increases the strong smell that acts as the repellent to these annoying pests. One way you can burn coffee grounds is to burn them the same as you would burn incense.

Just place them in a bowl or even in a ball of aluminum foil and light. Note: they must be dry grounds!

The smoke caused by burned coffee grinds is an amplified method to deter pests. The smoke itself repels many insects as it triggers their survival instinct, and they know to seek another place or perish.

Test #2: Coffee Ground Trails

When using coffee grounds to repel insects, simply lay a small layer under exterior doors as well as along the bottom of windowsills.

In fact, anywhere you notice that can be an entrance to pests, layer small amounts. Keep in mind to avoid high traffic areas to prevent a mess. When the coffee odor is no longer effective, simply sweep or vacuum it up. Reapply as necessary. This is an easy and safe method to build up a natural barrier!

Will Ants & Insects Stay Away from Coffee Grounds?

Coffee ground barriers can deter ants and insects either by odor or physically as they don’t like to tread on the grounds. However, keep in mind that due to the natural decrease in smell over time, it is important to periodically re-apply your coffee ground barriers to help keep insects away for good.

Some maintenance methods include:

  • Add fresh coffee grounds to old grounds
  • Spritzing old coffee ground traps with water
  • Spritz old grounds with vinegar or other homemade solutions
  • Remove old grounds and replace with fresh, used grounds
  • Add other ingredients such as essential oils, strong-smelling herbs, or Borax
  • Keep areas clean to avoid attracting other pests

Pesticides VS Natural Methods

There are so many “proven” methods to repelling and even killing nasty pests that are bound to enter our homes one way or another. But, when it comes to using common pesticides and other means of harsher repellents, you may unwittingly be choosing nasty side effects.

Because pesticides are inherently toxic, the risks to your health, pets, and garden-friendly animals may prove to outweigh the benefits of using them. Fortunately, there are some awesome points to consider when choosing what natural remedy to use to get rid of pesky pests!

Coffee grounds and other natural solutions are:

  • Environmentally friendly
  • Plant-based
  • Low or zero risk to health
  • Readily available in most households
  • Often used in recyclable forms
  • Cost-effective

Coffee: Natural DIY Insect Repellent!

With this information on hand, you might find yourself tempted to test a couple methods for yourself.

Some are cheap alternatives to pesticides and others are a great use of used coffee grounds.

Let’s face it, you’re bound to find some ants lurking around somewhere, so put your coffee grounds to use instead of chucking them out.

You might just find that it helps with other lurking insects too!