Killing Household Pests Using Boric Acid – Don’t Make These Mistakes

Boric acid is an odorless acid found in crystal or water soluble powder form has been known for many decades for its insecticidal properties. Thus, they are one of the most common and effective ways of killing household pests such as cockroaches, ants, fleas, and thermites while at the same time being mostly harmless to humans (unless in super large doses). Step into the storeroom of most households and there’s a good chance you’ll find a bottle of boric acid or products that contain boric acid, for this very purpose. Boric acid is typically applied to surfaces that pests travel on and the poison is transmitted to them when they walk over the powder. That said, there are three common mistakes that most people make when applying boric acid that is limiting its effectiveness. They are:

Mistake #1: Excessive Application

overuse-of-boric-acidMuch like that one lady at the nightclub, the most common mistake that people make is putting too much boric acid on a given surface. Remember, you want the pests to walk over the acid, meaning that the ideal application is a very thin and fine coat of boric acid. Excessive application leads to less of a fine coat and more of a toxic pile, and while insects are not known for their intelligence, a pile of boric acid in their path just causes them to walk around it instead of over it, defeating the purpose entirely.

So how do you determine what is a fine coat? A good rule of thumb is that you should barely, and I do mean barely, be able to see the boric acid coating with your naked eye. You can use a duster bulb or a good dustblower to achieve this; if you are using boric acid that comes preloaded in one of those plastic squeeze bottles, one neat trick is to partially cover the opening with your finger to ensure a smaller opening before squeezing out the powder. Make sure you shake the bottle first to avoid any clumps.

Mistake #2: Bad Location

Just like property investment, boric acid does no good if applied in the wrong location. Don’t just dust your house willy-nilly, we need to be more tactical in our application. This is a war after all, a war against household pests. You have to first understand your enemy and the most pervasive and dangerous enemy is the cockroach. The cockroach favors damp and dark places such as in cracks in the walls, under your fridge, stove, and washing machine. Another common area that many people miss is the void space underneath cabinets. You may have to drill small holes in the floors and backs of your cabinets in order to apply the boric acid. If you are not sure where exactly the roaches in your place are coming from, then it’s time to do a little reconnaissance: leave the lights off at night in the affected area for a few hours to lure them out. Then, enter the room and switch on the lights to see where they scurry off to. You now have your target locations.

Mistake #3: Overreliance

Boric acid is great, and more effective against insects than Charizard’s flamethrower attack against Venusaur. That said, many people become overly enamored with its effectiveness and neglect to use other pest control methods. Just like good investing, good pest management also requires diversification. However, you shouldn’t just simply mix and match like a colorblind woman at the Salvation Army clothing store; there are combinations that will enhance the overall effectiveness, and combinations that will reduce the overall effectiveness. Time to know which is which.

dead-roachLet’s begin with the no-nos. First, no glue traps. You see, boric acid poisoning can spread through a roach nest because roaches eat their dead. Hence, a roach killed by boric acid will poison its compatriots which feast on its corpse. That means you want a poisoned roach to make it back to its nest, not to get stuck in a glue trap. This is precisely how I eliminated my roach infestation using roach poison.

glue-trapWhat enhances overall effectiveness?  Roach baits are one such method. Now instead of depending on just applying the boric acid in the right locations, you can actively lure your enemy into your trap, making them even more effective. The opposite of luring also works; flushing them out. This can be done using various electronic pest repellents, however instead of merely using them to hopefully keep the roaches away (more likely it will just drive them into different hiding spots), you can use them to force them into a particular area of your house, such as the kitchen, where your numerous acid traps lie ready and waiting.


We would like to end this post with one final note: be patient. Rome wasn’t built in a day, and getting rid of pests such as roaches (which will be around long after the human race is extinct), takes time. You should allow at least two months for the treatments to take full effect, although you should see significant differences in roach numbers after the first month. Good luck, and happy hunting, and remember that an ounce of prevention is worth a pound of cure.