Natural Ant Killer: DIY with Safe Organic Ingredients


When you see ants in your home you don’t stop to identify what species they are, you just want them gone, NOW. Nobody wants dangerous pesticides in their kitchen or bathroom so we did the research to find the best natural ant killers made from safe organic ingredients you can use around children and pets.

The best homemade natural ant killer spray is an 8:1 solution of distilled white vinegar and liquid dish soap that kills ants in seconds. The best homemade natural ant killer bait is a 3:1 mixture of sugar and borax dissolved in water. Individual ants die in 48 hours giving the workers time to feed it to the queen and most colonies die within a week.

Here at Homeowner Answers we did more than 18 hours of research and spoke with experts to find the best natural ant insecticide solutions. We only make our recommendations after confirming effective results with our own testing. Search for natural ant killer and most of the information you find online is actually for ant repellents – we list these at the end of the post in case you have any questions.

If you are interested in identifying the species of your ant problem, a great source of information is your local Cooperative Extension Service. Every county in the United States has an extension office, follow this link to find yours.

Natural Ant Killer Spray

When ants are crawling in house you want to kill them quickly and discourage them from returning – a 8:1 solution of distilled white vinegar and liquid dish soap does both. We like the original blue Dawn, but you can also use plant-based biodegradeable soaps like Dapple Dish Soap (buy on Amazon) for a completely eco-friendly solution.

Put approximately 2 cups (500 mL) of distilled white vinegar in a spray bottle and add 1/4-cup (60 mL) of dish soap. Shake until well mixed and spray directly onto the ants.

You don’t need precise measurements to get results with this recipe – feel free to use more or less soap to get the right consistency to spray from your bottle.

How it Works: Ants don’t have lungs – they exchange oxygen and carbon dioxide through valves in their body called spiracles. The soapy water forms a film that clings to the ant’s body and interferes with the spiracle valves so the ant suffocates.

White vinegar can kill ants by itself but it is not nearly as effective because takes about an hour for the acetic acid to make its way through the exoskeleton. We also tested using dish soap mixed in water instead of white vinegar, this would kill the ants after we sprayed them but we noticed more ants kept coming back to the same area.

Ants communicate using pheromones, sounds, and touch. With their two antennae ants can detect the direction and intensity of scents, similar to how we use our ears to determine where a sound is coming from. Ants use scents to communicate where food is located and even their role in the colony – for example worker ants may be foragers, nest maintenance, or brood care. When a scout ant finds a food source they pick up a piece and put down a pheromone trail on their way back to the nest. Other ants follow the scent trail back to the food and they move quickly before the food source disappears.

Ants do not like strong odors because they interfere with the ant’s communication. Ants are repelled by many aromatic herbs & spices, essential oils, and vinegar. In addition to vinegar interfering with ants communication in general, white vinegar is a mild acid and very effective cleaner, especially when combined with dish soap. Spraying the ants to kill them and then wiping the area clean removes the pheromone trail the ants are following.

The combination of white vinegar and dish soap together gave the best results in our testing. It makes a quick killing spray and removes the scent trail so fewer ants return to the area.

Dish soap and water is an effective insecticide for many insects, including ants, wasps, and cockroaches. Although ants die almost instantly, wasps and cockroaches take longer to die and they need to be fully covered with spray. We use commercial sprays for stinging insect control, here is our favorite for a great price on Amazon.

Why its Safe: Both ingredients are probably already in your kitchen and used around food. You already use dish soap on your tablewear and distilled white vinegar is used for cooking (usually in sauces and marinades) and pickling vegetables. Avoid spraying it in your eyes and don’t ingest large amounts.

The easiest place to find distilled white vinegar is the grocery store and table vinegar is usually 5% concentration. Cleaning vinegar is also available and it is normally 6-8% concentration. These seem like small numbers but cleaning vinegar is much stronger than table vinegar – always read the label and know what you are working with.

Vinegar is an acid and should always be tested on a small inconspicuous area first. Do not use vinegar on natural stone, tile grout, aluminum, cast iron, or wood.

NEVER MIX VINEGAR WITH BLEACH: Mixing chlorine bleach with an acid, like vinegar, can produce chlorine gas that will irritate your eyes, nose and throat even and low levels. Higher levels of exposure can cause breathing problems, chest pain, and even death.

NEVER MIX VINEGAR WITH HYDROGEN PEROXIDE: Mixing vinegar and hydrogen peroxide together can create peracetic acid, a strong oxidizer and severe irritant to the skin, eyes, and respiratory system.

Natural Ant Killer Bait Recipes

Ants form social colonies of a few hundred ants up to several million individuals. Spraying a few ants crawling around your house won’t clear the problem until you eliminate the colony and the queen. This bait recipe uses sugar or protein to attract the ants and borax (buy on Amazon) to kill them.

Sugar Recipe: Combine 3-tablespoons (40 g) sugar with 1-tablespoon (25 g) borax and 1/2-cup (125 mL) hot water, then stir until everything is dissolved. Allow to cool.

Protein Recipe: Create a 2:1 mixture of peanut butter and borax. For example, mix together 2-tablespoons of peanut butter with 1-tablespoon of borax.

If the ants don’t feed on the bait, they are not bringing the borax back to the colony so it is best to use both types of baits. Sugar is usually the best bait for ants in your home but sometimes ants are looking for protein. Ants need liquid carbohydrates (sugar water) to feed all of the adults in the colony, but their young larvae and queen also need protein to grow. It really depends on what the colony needs at that moment. They are not common, but some ants are meat-eaters that don’t feed on sugar at all.

After ingesting the bait, individual ants will die in about 48 hours and most colonies will die in 7-10 days. Use multiple baits for large, established ant colonies and they may take additional weeks so make sure to refresh the baits after a week or two.

Natural Ant Killer Bait Containers and Placement

Put the bait into small containers and place them where you see ants. When possible, track the ants back to their nest or where they are entering the area. Put the bait at those locations makes it easy to access for the ants and they have even less reason to come into your house.

Bottle caps work great to hold the bait but they are prone to tip over, use double stick tape, rubber cement, or even a small dot of hot glue to hold them in place. Our favorite is to recycle the plastic condiment containers from our carryout and delivery food orders; just rinse them out, add the bait, and make a couple holes so the ants can get in.

Remember ants don’t like vinegar, so recycling container that held vinegar-based items like pickles or ketchup will be less effective. You can also purchase small containers with lids (buy on Amazon) for just a few dollars and always have them when you need them – they even have compostable options.

Here’s a great tip to get the baits into cracks and other small spaces where you see ants. Cut a drinking straw into 2-inch lengths and fill the straw with bait. This works great for the protein baits and with some modification you can also use sugar bait. Use only enough water to dissolve the borax and then add sugar until you get a syrupy gel consistency that will hold itself in the straw.

If the ants seem to ignore your baits then you need to adjust. The best way is to follow the ant trail to see what is attracting them and change your bait. In place of sugar you can try honey, syrup, fruit juice and even fruit slices. Try replacing peanut butter with bacon grease or cheese. When in doubt, mix borax with whatever the ants are already feeding on.

Sometimes ants will not feed on the bait if it has too much borax or too much/too little water. The ratios given are general starting points that work well in most situations but adjust to get the best results for your ant problem. Keep reducing the amount of borax until the ants take the bait – it will just take a bit longer to kill them because they get less with each bite.

How Borax Kills Ants

Borax kills ants in two ways. The primary mechanism happens when ants ingest the liquid bait. Borax disrupts the ant’s digestive system and they die from starvation after about 1 or 2 days. Ants share liquid food with the colony using a process called trophallaxis, each time they regurgitate the bait spreads to other ants, larvae, and the queen. Most colonies will die in 5-7 days but large colonies may take a few weeks.

Borax can also kill ants even if it isn’t ingested. When ants crawl through borax the powder scratches the ant’s exoskeleton causing them to lose body fluids and die. Sprinkling dry borax powder on ant trails and access points can also be effective to kill individual ants and keep them out of your home but baits work much better to kill the colony.

Fun Fact: most species of adult ants can’t eat solid food, their waist is so thin they can only consume liquid. Solid food is fed to their larvae who partially digest it and then regurgitate a liquid rich in nutrients for adults to eat. Ant larvae need protein to grow and workers provide protein and carbohydrates to the queen to lay more eggs.

Why Borax Ant Killer is Safe

Borax is a naturally occurring mineral that is commonly used in detergents, cleaners, cosmetics, teeth whiteners, fire retardants, and enamels. Borax powder is different from boric acid powder even though they look similar and have some similar properties. Both are found in nature but boric acid is commonly manufactured by reacting borax with a strong acid, such as hydrochloric acid.

BoraxBoric Acid
Chemical NameGenerally: sodium borate
Also: sodium tetraborate, disodium tetraborate
Generally: hydrogen borate
Also: boracic acid, orthoboric acid
Chemical FormulaNa₂[B₄O₅(OH)₄]·8H₂OH3BO3
AppearanceWhite, odorless, crystalline solidWhite, odorless, crystalline solid
Solubility in Water65.63 wt% at 100 °C27.53 wt% at 100 °C

You can find many people online making contradicting claims about just about everything so we researched the science and consulted the experts. Borax was commonly used as a food additive and preservative until 1961 when the World Health Organization issued NMRS 31/TRS 228-JECFA 6/37 with an acceptable daily intake (ADI) of zero for borax.

Based on its studies, the EPA concluded that borax present no hazard to the public health under 40 CFR 180: Pesticide Tolerance Exemptions.

EPA has determined that, because they are of low toxicity and occur naturally, boric acid and its sodium salts should be exempted from the requirement of a tolerance (maximum residue limit) for all raw agricultural commodities.

EPA

California does not list borax on their famous Proposition 65 list of chemicals known to cause cancer or birth defects or other reproductive harm. Borax was reviewed and not listed, but breathing the air in a parking garage, drinking coffee, visits to your dentist, taking aspirin, and even some peanut butter were danger enough to require warnings.

As Paracelsus wrote in 1538, “the dose makes the poison”. A basic principle of toxicology is that all chemicals – even water and oxygen that we need to live – can be toxic if too much is eaten, drunk, or absorbed. A daily vitamin supplement can be very beneficial, but eating the entire bottle in one sitting will cause ill effects.

Unintentional ingestion of small amounts of borax can cause nausea, vomiting, abdominal pain, and diarrhea.

National Capital Poison Center

Many people think that borax is a manufactured chemical but in reality it is 100% natural. Borax is a naturally occurring mineral that is simply mined and packaged.

Rio Tinto borax mine by Marcin Wichary

Natural Ant Killer Barrier

The best barrier treatments are safe, effective, low maintenance, and long lasting – food-grade diatomaceous earth (DE) checks all the boxes. Simply sprinkle DE powder in low traffic locations where it won’t be disturbed or wash away: crawlspaces, wall voids, weepholes, under appliances, garden sheds, basements and storage spaces. You don’t need to use a lot but it can get messy so take your time.

For precise application and to avoid the dust issue completely simply mix the diatomaceous earth with water and spray where you want it. Add 1-cup of DE to 1-quart of water (100-g of DE with 1-L of water) to create a slurry. The DE will settle to the bottom of the bottle during use because it does not dissolve in water so be sure to shake frequently while spraying to keep it suspended.

How Diatomaceous Earth Kills Ants

Diatomaceous earth is a naturally occurring soft rock that easily crumbles into a soft white powder. DE is not really earth soil, it is actually the fossilized shells of tiny marine algae from ancient bodies of water. They accumulated in sediment layers and are mined today. The shells are made of silica in the form of silicon dioxide, and the tiny skeletons and shells have sharp jagged edges as they break.

Diatomaceous earth is not a poison or a chemical, it works by mechanical action. All of those microscopic shells have sharp edges that cut and abrade the ants as they move through. The diatoms cut through the ant’s waxy outer layer and disrupting their internal water balance – the ant dries out and dies. DE is effective on many other unwelcome pests like termites, spiders, cockroaches and even scorpions.

Diatomaceous earth will not kill bugs while it is wet. Because of the surface tension of water, the sharp edges of DE are inside the water droplets and bugs can walk through unharmed. Even high humidity and damp locations reduce DE effectiveness so it is best used indoors. After diatomaceous earth dries out it recovers its bug killing properties.

Low Maintenance and Long Lasting: Once you put the diatomaceous earth barrier in place you don’t need to do much. Check it 2-3 times per year and replenish any disturbed areas but as long as DE is present and dry it will continue working.

Why Diatomaceous Earth is Safe

Food-grade diatomaceous earth is safe for humans and pets to ingest and approved by the EPA, FDA, and USDA. DE is even registered as an external flea control for cats and dogs. DE dust is an irritant so try not to get it on your skin and avoid getting it in your eyes or breathing the dust.

Use food-grade diatomaceous earth. Even though you don’t plan to eat it you still want to get food-grade diatomaceous earth because it has less than 1% crystalline silica. Filter grade DE (or pool grade) has been heat treated and activated through a process called calcination that hardens the diatom exoskeletons and converts silicon dioxide to crystalline silica. Calcination make filter grade DE perform better in filters but crystalline silica is hazardous and requires additional safety precautions.

What is the Fastest Way to Get Rid of Ants?

Natural ant killer spray works on contact and diatomaceous earth works great as a barrier, but neither will kill the colony because the queen is safe in her nest making more ants. Using natural ant killer bait is the best long-term solution to control ants. Worker ants bring the bait back to the colony where it gets fed to the larvae, other workers, and eventually the queen. The process takes time, 7-14 days for most colonies, and longer for large colonies or if the ants don’t take much bait.

The quickest way to get rid of ants is to use all three methods together, but first you have homework to do. Spend some time watching where the ants come and go, you need to find their trails and where they lead. What food/water sources are they using? Where do they travel? If they disappear into a wall or ceiling, look on the other side (including outside) and continue following them. Use a flashlight to peer into dark areas like cracks and corners and mark their holes with blue painter’s tape.

  1. Remove whatever is attracting the ants. You need to make it clean and dry so the ants don’t have any reason to come back. Use drain cleaners and close the drain stopper after you are finished. Spray your counters to degrease and clean them. Vacuum crumbs out of your drawers and shelves. Put food into airtight containers or the refrigerator/freezer. Sweep and vacuum the floors.
  2. Spray the ant trails with natural ant killer spray. Spray and wipe clean any and all surfaces where you saw the ants traveling. You want to wipe out their highways of pheromone trails.
  3. Place natural ant killer baits right next to all holes or cracks the ants are using. Even if you think they are just going in one side and out the other put a bait on both sides so you get them coming and going. Ants can form splinter colonies when stressed and don’t need much room at all.
  4. Put diatomaceous earth in a circle around the ant hole and your bait. You want a little cul de sac so the ant can come and get to the natural ant killer bait but that’s all – to get anywhere else they would need to cross the diatomaceous earth…and die.
  5. Walk the perimeter of your house outside and look for ant activity. Many indoor ants come from outdoor colonies, so be thorough. Look on the ground and in landscaping next to your house. Go slow and check your foundation weepholes, exterior walls, windows and doors. You can use natural ant killer spray and bait outside as well as DE, but we prefer to use a longer lasting contact insecticide – here is our favorite barrier spray for a great price on Amazon.

Follow this comprehensive plan of attack to keep the ants under control until the borax bait has time to get into the colony and take out the queen.

Other Natural Ant Killers and Repellents

MaterialEffectivenessDetails
Baking SodaWeak effectBaking soda showed only slightly higher mortality than control group
Cinnamon Oil
(Cinnamon Leaf Oil and Cinnamon Bark Oil)
Kills and repels ants
Not safe for cats or dogs
Cinnamon extracts kill and repel ants but effectiveness fades quickly. Extracts contain eugenol and trans-cinnamaldehyde, both studied on fire ants.
Child safe and leaves no oily residue; dilute to 1% or less to avoid skin irritation.
Cinnamon SpiceRepels antsSprinking cinnamon directly onto an anthill may kill ants if they inhale the powder but the colony will survive.
Strong smell can deter and confuse ants. Child safe and pet friendly.
Citronella OilKills and repels ants
Not safe for cats or dogs
Strong smell can deter and confuse ants, citronella oil can kill ants with prolonged (24 hr) exposure. Child safe and pet friendly.
Clove OilKills and repels ants
Not safe for cats
Clove oil contains eugenol compound that kills and repels ants.
Coffee GroundsWeak effectStrong smell may deter ants while they are wet and fresh, replace grounds daily.
CornstarchWeak effectCornstarch can suffocate ants if they are covered.
Lemon OilRepels antsDoes not kill ants, strong smell can deter and confuse ants. Child safe and pet friendly.
Lemon Eucalyptus Oil
not the same as oil of lemon eucalyptus
Repels ants
Not safe for cats or dogs
Lemon eucalyptus oil contains citronella, strong smell can deter and confuse ants.
Neem OilWeak effectA study by Texas A&M University showed no statistical difference in the number fire ant mounts in plots treated with neem oil. Neem products may inhibit feeding and disrupt growth.
Oil of Lemon Eucalyptus (OLE)
not the same as lemon eucalyptus oil
Repels ants
Not safe for cats or dogs
OLE contains up to 70% p-Menthane-3,8-diol (PMD) that is comparable to DEET as an insect repellent and is registered with the EPA with no expected health risks.
Pepper
(Black Pepper and Cayenne Pepper)
Repels antsDoes not kill ants, strong smell can deter and confuse ants. Child safe and pet friendly, but can cause a burning sensation.
Peppermint OilRepels antsStrong smell can deter and confuse ants, peppermint oil may kill ants with prolonged (24 hr) exposure. Child safe and pet friendly.
Tea Tree OilRepels ants
Not safe for cats or dogs
Strong smell can deter and confuse ants, tea tree oil may kill ants with prolonged (24 hr) exposure. Child safe.

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