The cockroach myths that keep infestations going

Most people with cockroaches have already tried something. Usually several things. A spray, a fogger, a plug-in, a sprinkle of baking soda behind the fridge. When none of it holds, it is easy to conclude that cockroaches cannot be beaten. They can. But a handful of myths keep sending people down the wrong road, and while they do, the cockroaches in the walls keep breeding.

Here are the ones we see most, why each one sounds right, what really happens, and what works instead. No judgement for having believed any of them. They are everywhere.

“Clean homes don’t get cockroaches”

Why it sticks: crumbs and grease do feed them, so dirt feels like the cause. What happens: people scrub harder, feel ashamed, and tell nobody, which delays the plan. Cockroaches arrive in deliveries, shopping, second-hand things and through pipes from next door. They come for warmth and water as much as food, and they turn up in spotless flats and new buildings.

What works: cleaning helps, because it takes food away from them and makes bait more attractive. But it is one step of the plan, not a test you failed. Why do I have cockroaches when my home is clean? covers how they get in.

“Raid will sort it”

Why it sticks: spray kills the cockroach in front of you, instantly. That feels like progress. What happens: most of them are hidden in cracks, hinges and behind appliances, where spray does not reach. Spray near bait can also put them off the bait, so the thing that would reach the hidden ones stops working.

What works: stop spraying near bait, put gel in the hiding spots, and count with traps. Why doesn’t Raid get rid of my cockroaches? explains the switch.

“A fogger clears the whole flat”

Why it sticks: one can, one afternoon out, every room covered. What happens: the mist settles on open surfaces and rarely reaches the cracks where cockroaches live. In a block of flats it can push them next door, and back again later. It also leaves residue on everything.

What works: bait, a growth regulator and traps, which go where the cockroaches are. Do cockroach foggers work? covers the label and safety points if you have already used one.

“It was just one”

Why it sticks: you saw one, then nothing, and maybe a pest controller found nothing either. What happens: sometimes it really was a stray. Sometimes it was the one you happened to see from a group hiding nearby. A single visit or a single sighting is a snapshot.

What works: monitor traps, checked weekly for a few weeks. Empty traps and no droppings mean a visitor. Young ones on a trap mean breeding nearby. I saw one cockroach walks through it, and baby cockroaches, what now? covers the next step.

“Baking soda kills them, peppermint keeps them away”

Why it sticks: both are cheap, already in the cupboard, and feel safe. What happens: there is no good evidence that baking soda clears an infestation, and a cockroach in a kitchen has better things to eat. Peppermint may make one take a different route for a while. It does not kill the ones hiding, does not touch egg cases, and fades.

What works: the same cheap basics, done in order. Do baking soda, peppermint or borax kill cockroaches? also explains why homemade borax mixes are a risk around children and pets.

“An ultrasonic plug keeps them out”

Why it sticks: the box is convincing, the reviews are glowing, and you cannot hear it, so you cannot tell it is not working. What happens: the cockroaches carry on. Reviews tend to be written in the first days, and any quiet spell gets credited to the plug.

What works: nothing that plugs into a socket. Do ultrasonic pest repellers work? has the detail. Shoo does not make, sell or recommend them.

“The cat will deal with them”

Why it sticks: cats do catch the odd one, and sometimes bring it to you. What happens: the cat cannot reach the cockroaches living inside walls, hinges and appliances, which is where most of them are. You see fewer without having fewer.

What works: the plan below, with bait placed where the cat cannot get to it. Is pest control safe for my cats and dogs? covers the pet side.

“Throw out the microwave and they’re gone”

Why it sticks: you saw them come out of it, so it feels like the nest. What happens: cockroaches like the warmth of microwaves, printers and routers, but they live all around the kitchen too. People replace the appliance and find them in the new one within weeks. Binning a cupboard’s worth of things goes the same way.

What works: unplug it, never spray inside electronics, and bait around the appliance rather than in it. Cockroaches in my microwave has the steps.

“We’re too high up to get them”

Why it sticks: cockroaches seem like a ground-floor, drains-and-cellars problem. What happens: in a block of flats, they travel through pipe runs, shared walls and service gaps, and they ride up in bags and boxes like everyone else. A high floor makes no difference to the German cockroach, which lives indoors.

What works: seal around pipes, bait along the walls you share, track with traps, and ask the building in writing to treat the source. Cockroaches keep coming from next door covers the plan, and our page for renters covers what to send. Who has to act varies by country: in the UK, council environmental health can advise, and elsewhere the local housing authority or a tenants’ union.

What works, in order

For the small indoor German cockroach, the established approach is short, and every myth above is a detour from it.

1. Take away water and food. Dry the sink at night, fix drips, clear grease behind the cooker, seal food away.
2. Close the gaps around pipes and behind kickboards. See sealing gaps.
3. Put out monitor traps to see where they are and how many.
4. 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. What is a growth regulator? explains it.
6. Count weekly, and do not spray over the bait.

What do I need for German cockroaches, and in what order? covers where each one goes. Big dark ones coming up the drain are usually a different story: see big dark cockroach at night.

Kids and pets: bait and growth regulators are regulated products. Follow the label, put them behind appliances and inside high cupboards, and leave out anything whose label warns against use around children or pets. Our safety page has more.

Falling trap counts mean keep going. Flat or rising after a month means change the plan or get help. DIY or a professional? helps you decide, and seeing more since I treated explains why a short rise can be normal.