Borax and boric acid are both boron-based compounds used in pest control, but they are NOT the same thing. Boric acid (H3BO3) is a refined, purified chemical. Borax (sodium tetraborate, Na2B4O7) is a naturally mined mineral. Both kill insects, but boric acid is more potent and is the standard in professional pest control.
Both target the same pests: cockroaches (especially German cockroaches), ants, silverfish, firebrats, carpenter ants. Boric acid is also used for wood treatment (Boracare) against termites and wood-boring beetles. Borax is the base for many DIY ant bait recipes.
Boric acid products: Harris Boric Acid Roach Powder, InTice Thiquid Ant Bait, Niban Granular Bait, Boracare (wood treatment), Terro Ant Baits (borax-based), homemade sugar + borax ant bait. 20 Mule Team Borax (laundry product used in many DIY pest control recipes).
Both are low-moderate toxicity to mammals. Keep away from children and pets. Toxic if ingested in quantity - roughly 1-2 teaspoons of boric acid can be dangerous to a small child. Borax has similar toxicity.
The key differences:
| Property | Boric Acid | Borax |
|---|---|---|
| Chemical formula | H3BO3 | Na2B4O7 · 10H2O |
| Boron content | 17.5% | 11.3% |
| Pest kill potency | Higher (more boron per gram) | Lower (needs more product) |
| EPA registered as pesticide | Yes - many products | Not as a standalone pesticide |
| Best use | Professional dust, commercial baits | DIY liquid ant baits |
| Cost | $5-10 per bottle | $5-8 per box |
For cockroaches: Use boric acid powder (Harris or equivalent). Apply a THIN film in cracks, crevices, behind appliances, and inside wall voids. The number one mistake is applying too much - if you can see piles or lines of powder, insects will walk around it. A barely visible film is ideal.
For ants (DIY bait): Mix 1 tablespoon 20 Mule Team Borax + 1/2 cup sugar + 1.5 cups warm water. Soak cotton balls and place along ant trails. The low borax concentration (about 5%) allows ants to feed and carry bait back to the colony before dying. Higher concentrations kill too fast for colony transfer.
Professional recommendation: For serious pest control, use EPA-registered boric acid products rather than DIY borax recipes. The commercial products have been formulated and tested for optimal particle size, concentration, and bait attractiveness.