Diatomaceous Earth vs Borax for Ants: Which One Should Canadians Use?

What Is the Difference Between Diatomaceous Earth and Borax?

Diatomaceous earth and borax differ in how they kill: diatomaceous earth dries ants out on contact, while borax poisons ants that eat it. That single difference explains almost everything else, from how fast they work to whether they reach the colony.

What Is Diatomaceous Earth?

Diatomaceous earth is a powder made of crushed microscopic marine fossils, according to Health Canada. The National Pesticide Information Center (NPIC) explains that these fossils are the remains of tiny aquatic organisms called diatoms, and the Government of British Columbia describes the powder as silicon dioxide. It is not a poison.

How Diatomaceous Earth Kills Ants

Diatomaceous earth kills ants physically. When an ant crawls through it, the powder absorbs the oils and fats from the ant's waxy outer layer, and its sharp edges scratch that layer, so the ant dries out and dies (NPIC, Health Canada). The ant does not need to eat it. The catch, as Health Canada notes, is that it stays active only while it is kept dry, and it only works on the ants that actually touch it.

What Is Borax?

Borax is a boron compound, one of the sodium borate salts, according to NPIC, and UC IPM lists it among borate bait ingredients. It is the active ingredient in many ant baits. In ant bait stations, it appears on the label as sodium tetraborate decahydrate.

How Borax Kills Ants

Borax kills ants as a slow stomach poison. Ants usually ignore plain borax, so it goes in sweet baits, as Penn State Extension advises for sweet-loving ants. Worker ants drink the bait, carry it back to the nest and share it with the other ants, including the queen. According to NPIC and the Government of British Columbia, boron compounds such as boric acid work as a stomach poison in insects that eat them. The effect is slow, so the workers live long enough to spread it through the colony.

Borax vs Boric Acid

Borax and boric acid are not the same product, but they are close relatives. Both are boron compounds, and NPIC notes that their toxicity depends on how much boron they contain. Health Canada even groups them together in its rules, noting that boric acid is "sometimes also called boron or borax", and UC IPM lists both among borate products. For the acid form, see our guide to boric acid for ants.

Diatomaceous Earth or Borax for Ants: Which Works Better?

Diatomaceous earth or borax for ants comes down to your goal: borax bait can reach the queen and the colony, while diatomaceous earth only kills the ants that touch it. Here is how they compare on the points that matter at home.

Killing the Colony

Borax wins on colony control. UC IPM explains that a slow-acting bait can kill the entire colony, including the queens, because workers feed it to the nest. Diatomaceous earth does not do this: Health Canada says it scratches ants so they dehydrate and die, and pest control companies such as Terminix and Dodson Bros point out that only the ants that contact it die, so it will not eradicate a colony on its own. The City of Calgary also describes ant baits as a highly effective way of eliminating nests, and UC IPM notes they attract worker ants looking for food.

Speed

Diatomaceous earth is faster on individual ants, and borax is faster at ending the problem. Orkin reports that diatomaceous earth takes a few hours to a few days to kill an insect, depending on conditions. Borax bait is slower to show results: UC IPM says it can take 5 to 10 days to see fewer ants, and complete control may take longer. TERRO says complete control with its borax stations may take up to two weeks, and 2 to 3 weeks for larger colonies; Penn State Extension notes it may take two weeks or longer. Expect more ants on the bait at first: UC IPM notes they recruit other workers to it, a sign it is usually working.

Moisture

Moisture favours borax. Health Canada says diatomaceous earth stays active only as long as it is kept dry, and the Harris diatomaceous earth label says it is less effective when relative humidity is above 65%. That matters in damp basements, bathrooms and humid Canadian summers. Borax bait stations are closed, so the bait stays usable whatever the weather, although you still need to replace them when they empty.

Which Ants Each One Works On

Neither product suits every ant. The Harris diatomaceous earth label covers ants but excludes fire, harvester, carpenter and pharaoh ants. TERRO's borax bait is made for sweet-eating ants such as odorous house ants, little black ants and pavement ants, and it is not effective on fire ants or meant for carpenter or pharaoh ants. Health Canada lists carpenter, little black, odorous house, thief and pharaoh ants among the species that invade Canadian homes, so it is worth identifying yours first. If you see large black ants and sawdust, read our guide on how to get rid of carpenter ants. Tiny yellowish ants indoors may be pharaoh ants, which UC IPM says to control with bait, because sprays can make their colonies split.

Ease of Use

Both are easy, in different ways. A ready-made borax bait station is open, place and wait, with nothing to measure. Diatomaceous earth needs a little skill: a thin, light coat, since Orkin notes that ants avoid thick layers, applied with a duster and gloves so you do not breathe the dust.

How Long Each One Lasts

Diatomaceous earth stays active as long as it is kept dry (Health Canada), but it needs reapplying after it gets wet or is cleaned up, according to Bug Out Service. Borax bait stations last until the ants drain them or the bait dries out. Once the ants are gone, TERRO suggests replacing stations every 3 months to catch new arrivals.

In short:

• Choose borax bait for an active trail of small sweet-eating ants coming from a nest you cannot reach.
• Choose diatomaceous earth for a dry, low-toxicity barrier in cracks, wall gaps and entry points.
• Choose neither alone for carpenter ants or pharaoh ants.

Borax for Ants in Canada: What Is Still Allowed?

Borax for ants in Canada now means sealed bait stations or localized gels, because Health Canada cancelled domestic borax dusts and loose borax liquids. If an older guide tells you to sprinkle borax powder around your house, that advice no longer fits Canadian rules.

Cancelled Borax Dusts and Powders

Health Canada re-evaluated boron pesticides, including boric acid and borax, and found that overexposure could cause developmental and reproductive health effects. As a result, domestic boron pesticides in dust or granular form, and products in solution other than sealed bait stations or localized gels, were cancelled. Their sale was prohibited as of July 22, 2018, and they were cancelled as of July 22, 2019. In its 2016 announcement, Health Canada said 25 of the 112 registered boric acid products would be cancelled, and the other 87 would get stronger labels.

Borax Bait Stations and Gels

Borax bait stations and gels remain on Canadian shelves. Health Canada advises looking for a Pest Control Products (PCP) number on the label, which shows the product is approved for use in Canada. Health Canada also advises placing bait stations out of the reach of children and pets. For a step-by-step method, see our guide on using borax to kill ants, and for tested products, our best ant killer roundup.

Homemade Borax Bait

Homemade borax bait is something Health Canada advises against: it recommends not making homemade pesticides with boric acid, and it notes that borax can produce boric acid. The concern is combined exposure in the home, especially for children. A store-bought sealed station keeps the bait away from little hands and paws.

Bait Strength

Bait strength decides whether borax reaches the colony. UC IPM notes that prepackaged stations usually contain 5.4% borate, while liquid borate at 0.5 to 1.0% in sugar water has more impact on the colony, because ants that eat a weak bait live longer and share it more. A bait that is too strong kills the workers before they get home. This is one more reason the old "equal parts borax and sugar" recipe does not work well.

Is Diatomaceous Earth or Borax Safer Around Children and Pets?

Diatomaceous earth and borax are both low in toxicity, but each has its own risk: diatomaceous earth is a dust you should not breathe, and borax is a poison children and pets should never eat. Health Canada calls diatomaceous earth non-toxic to humans and pets, and says baits containing boric acid are generally of low toxicity to other animals. Placement and handling make the difference.

Breathing Diatomaceous Earth Dust

Diatomaceous earth can irritate your nose and nasal passages if you breathe it in, and very large amounts may cause coughing and shortness of breath (NPIC). Use only food grade diatomaceous earth or a registered ant dust, never pool grade. Pool filter powder is heat-treated, and the New Jersey Department of Health reports it can contain crystalline silica, which NPIC links to silicosis with long-term inhalation. For example, Wilson Ant Out Ant Killer Dust, made by Premier Tech in Quebec, carries PCP number 21936. Our guide to diatomaceous earth for ants covers safe application and cleanup.

Borax Exposure

Borax is mainly a risk if swallowed or splashed in the eyes. NPIC reports that borax can be corrosive to the eye and irritating to the skin, and that people who swallowed boric acid had nausea, vomiting, stomach pain and diarrhea. Wear gloves when handling bait, keep it in its closed station, and if someone swallows bait, call your local poison centre with the label in hand.

Pets

Pets are safer with sealed stations and dry, out-of-reach dust. NPIC notes that in animals, signs of boron poisoning can start within hours of eating it, so place borax stations where your dog or cat cannot reach them, as Health Canada advises. Diatomaceous earth is not poisonous, but keep pets out of the area while the dust settles. If your pet does eat bait, call your veterinarian. For more options, see our list of pet-safe ant killers.

Garden Use

Neither product is harmless in the garden. The Government of British Columbia notes that diatomaceous earth kills insects by causing them to dehydrate, and that can include bees, ladybugs and other beneficial insects, so keep it away from flowers. NPIC notes that borax can kill plants by drying them out and that boric acid can move through soil with water, so do not sprinkle it on beds or lawns.

When Should You Use Diatomaceous Earth, Borax or Both?

Diatomaceous earth suits dry cracks and entry points, and borax bait suits an active trail coming from a nest you cannot reach. Many homes benefit from using each one in its own place.

When to Use Diatomaceous Earth

Use diatomaceous earth when ants come in through dry gaps you can reach: cracks along baseboards, behind and under appliances, window frames and wall voids. The City of Calgary describes it as a non-chemical option for cracks, crevices and colony locations, and Health Canada notes it can be placed in cracks and crevices and that nests in wall voids may be treated with dusts puffed into the area. Apply a thin coat, keep it dry, and reapply if it gets wet.

When to Use Borax Bait

Use borax bait when you see a steady trail of small ants on a counter or floor. Place the station directly on the trail, out of reach of children and pets, remove other food sources, and leave the ants alone while they feed. Health Canada warns not to use chemical sprays while baiting, and UC IPM notes that sprays can disperse pharaoh ant colonies to new locations.

Using Both Together

Using both together works if you keep them apart. Put borax stations on the trails and keep diatomaceous earth off those trails, so the workers survive long enough to carry the bait home. Use the dust at entry points and in voids away from the bait. Once the trail is gone, sealing those entry points is the longer-term fix.

Other Natural Ant Remedies

Other natural remedies such as dish soap sprays and essential oils kill or repel the ants they touch, but like diatomaceous earth, they do not reach the nest. If you want to try one, our guide to dish soap for ants explains what it can and cannot do.

When to Call a Pest Control Professional

A licensed pest control professional is worth calling when you see carpenter ants or sawdust near wood, when ants keep coming back after several weeks of baiting, or when they show up in several rooms at once. A professional can identify the species and treat nests inside walls. You can get a quote from a recommended local exterminator through Pest Agent's referral form, or browse all our ant guides first.