Do baking soda, peppermint or borax kill cockroaches?

Mostly no. It makes sense to want something cheap that feels safe. But baking soda and peppermint do very little against cockroaches. Borax is a real insecticide, yet homemade borax mixes can do more harm to a child or pet than to the cockroaches. The options that do work are not expensive either, and they are made to be used safely.

Baking soda

The story goes that cockroaches eat it and burst. There is no good evidence that baking soda clears an infestation. In a home with crumbs, grease and pet food around, a cockroach has better things to eat than a dusty powder. Meanwhile the ones in the walls keep breeding while you wait for it to work.

Peppermint and other oils

A strong smell may make a cockroach take a different route for a while. It does not kill the ones already hiding, it does not touch egg cases, and it fades. Surrounding moving boxes with peppermint and lemon oil will not stop a cockroach that is already inside a box or tucked into an appliance.

For a move, what helps is checking things as you pack, leaving cardboard behind where you can, and putting traps down in the new place. Our page on moving without bringing cockroaches has the steps.

Borax and boric acid

Boric acid is a real insecticide, and it is used in some registered cockroach products. The problem is the homemade version. A mix of borax and sugar has no label, no tested strength and no instructions. It looks and smells like food to a toddler or a dog, and loose powder on the floor gets walked through and licked off paws.

If you want to use boric acid, buy a product registered for cockroaches where you live, put it only where the label says, and follow the label exactly.

A cat

Cats catch the odd one, and some are proud of it. But a cat cannot reach the cockroaches living inside walls, hinges and appliances, which is where most of them are. It might bring down the number you see without touching the number you have.

What works, without spending much

1. Take away water and food. Dry the sink at night, fix drips, clear grease behind the cooker, store food in sealed containers.
2. Close gaps around pipes and behind kickboards. See sealing gaps.
3. Put out monitor traps to see where they are and how many.
4. Use gel bait in small dots or closed bait stations where they hide.
5. Add an insect growth regulator so the young cannot become breeding adults.
6. Count weekly and do not spray over the bait.

The German cockroach guide has the full plan. These are regulated products: follow the label, and check each one is allowed where you live.

Kids and pets: closed bait stations are harder for little hands to get into than loose powder or gel. Still put them behind appliances and inside high cupboards, and leave out any product whose label warns against use around children or pets. Our safety page has more.

Is my setup working?

A baby cockroach every few days, a few weeks in, can be normal while eggs hatch. What matters is the trend in your trap counts. Falling means keep going. Flat or rising after a month means it is time to change the plan or get help. Our page on DIY or a professional helps you decide.

One note if the bug turned up on a second-hand bed. Small bugs on a headboard at night can be bed bugs as easily as cockroaches. Do not spray the bed. Catch one on clear tape, compare it with our bed bug guide, and see how to check second-hand furniture.