How to Use Borax in the Dishwasher to Get Rid of Roaches

An old adage has it that if a nuclear war were to destroy all life on the planet, there would still be cockroaches. Whether that's true or not, and hopefully we'll never know, there's no doubt that roaches are hardy and turn up in all sorts of places around the house. They especially like the dishwasher because it's a dark, moist and warm environment, so if you're doing the nightly dishes and you open the dishwasher door only to find a roach scurrying for cover, you won't be the first person to whom that has happened.

You might think you could discourage roaches from entering the dishwasher by keeping the door open, but they'll probably just go underneath or into the control panel, which are two favorite hiding places, and stay there until you finally give up and close the door. Nothing short of an attack strategy will solve the problem, but what can you use to get rid of roaches in the dishwasher control panel? Borax may just be the weapon you need.

You definitely don't want to use a conventional insecticide, such as Raid, because spraying Raid in a dishwasher is dangerous, and pest control experts caution against it. You also won't have much luck getting rid of roaches in the dishwasher with bleach. Borax is effective and safe to use, though, and it's deadly to roaches that eat it, so you just have to find a way to encourage them to do that.

Borax and boric acid both contain boron, but they're two different compounds, and boric acid is the one most used as an insecticide. One of the main reasons for this is that boric acid granules are small and therefore easier for ants and other small insects to ingest. Cockroaches aren't small, though, and they can handle larger borax granules, so the laundry detergent additive is often used for roach control, although boric acid is better.

Neither boric acid nor borax kill by contact. For either to work, the roaches must ingest the powder. When they do, the compounds interfere with their digestive processes and kill them.

You can trick the roaches in the dishwasher front panel into eating borax in one of two ways. One is to spread a thin film of the powder in their path and force them to walk through it and ingest it when they groom themselves. The other is to make a bait by mixing it with something sweet.

If you're serious about getting rid of the roaches in your dishwasher, you need to invest some time because it takes time for the roaches to fall into the trap and it takes even more time for them to die. Dusting the inside of the dishwasher can work only if the dust stays dry. This is possible only if you can avoid using the dishwasher for perhaps a week or two and wash your dishes by hand.

Start by opening the dishwasher door and leaving it open for a few hours to allow the inside to dry out. Once it's dry, dust a very thin film of borax or boric acid powder on the bottom and all horizontal surfaces. This dusting should be almost imperceptibly thin because if it's too thick, the insects will simply walk around it or avoid the dishwasher altogether.

While you're at it, remove the base plates from the dishwasher, refrigerator and stove and dust underneath them. It's also a good idea to clear out the kitchen cabinets and dust all the horizontal surfaces inside. Make sure each place you dust stays dry for the treatment period, which should be at least a week.

Borax and boric acid baits are known to be effective, and many over-the-counter roach bait traps include one or the other — usually boric acid — as the lethal ingredient. The problem with this approach is that you can't put bait inside the dishwasher if you plan to use it, but since the roaches are likely living all around the dishwasher as well as inside it, you probably don't have to.

Make the bait by mixing boric acid or borax powder (preferably boric acid) with a dough made with flour, milk, salt and some chopped onion. Then, roll the mixture into balls. Place these balls under the dishwasher, inside the kitchen cabinets, under the stove and refrigerator and any other dark place where pets and children can't get them. Borax is about as toxic as laundry detergent and probably won't make anyone sick, but it's better to play it safe.

It will take time for the roaches to find the bait, eat it and die, so you'll want to replace the bait balls every week or so to keep them fresh. Keep the bait stations dark because roaches prefer dark spaces and will probably stay away if there's any light. It's also fine if the areas are damp because the moisture will help attract the roaches to the bait.

By themselves, borax and boric acid dustings and baits may not kill all the roaches in your dishwasher. You may want to increase your chances of success by using an additional control method. However, if the borax strategy is successful, the ones that are poisoned will probably return to nests in places such as the dishwasher control panel and kill the ones hiding out there. They do this by dying and becoming food for the others in the nest.

To make sure this happens, it's important to avoid combining borax with insecticide sprays that kill on contact. If the bugs die on the spot, they won't go back to the nest, and they may even prevent other roaches from approaching the dust or bait. Avoid deploying sticky traps for the same reason.

However, a roach gel that contains boric acid is a great supplement to a baiting or dusting regimen. The advantage of a gel is that you can apply it to walls, especially near holes where pipes pass. Moreover, gels usually contain attractants that roaches can't resist, and when used in conjunction with bait, they make the bait more attractive.