You sprayed. You scrubbed the counters. For a few days the kitchen was quiet. Then you switched on the light late one night and there they were again, running for the gap behind the cooker.
If you’re wondering why cockroaches keep coming back, it’s probably not something you’re doing wrong. Cockroaches are very good at surviving the things most people try first. Once you understand how they live, it’s much easier to see why the problem returns, and what it takes to end it.
Which cockroach do you have?
It helps to know what you’re dealing with, because the two common kitchen cockroaches behave differently.
The small one is usually the German cockroach. Adults are about 13 to 16 mm long, light to dark brown, with two dark stripes running down behind the head. These live indoors, close to food and water: in kitchen cabinets, behind the fridge and cooker, under the sink and inside appliances. If your cockroaches are small and you see them in the kitchen, this is almost certainly the one. It’s also the one that keeps coming back.
The big one is the American cockroach. It’s much larger, reddish-brown, and often comes up from drains, sewers and outside areas, especially at night or after rain. Seeing the odd big one doesn’t always mean an infestation inside, but it does mean there’s a way in.
Why cockroaches keep coming back
1. The eggs survive the spray
This is the big one. A German cockroach female doesn’t lay eggs loose. She carries them in a hard brown capsule at the tip of her body until they’re about to hatch. Each capsule holds around 40 eggs, and one female can produce five to eight capsules in her lifetime.
That capsule protects the eggs from a lot of what you spray. So you kill the adults you can see, the house goes quiet, and a few weeks later a new batch hatches. It looks like they came back, but they were there the whole time.
2. Most of them are hiding where you can’t see
For every cockroach you see running across the floor, there are many more in the cracks, behind the cabinets and under the appliances. They gather in groups close to food and water, and the young ones stay hidden. A spray on the floor or counter barely touches them.
3. Shop sprays can scatter them
Many household sprays repel cockroaches as well as killing the ones they hit directly. The survivors move away, deeper into the walls, into the next room, or into the flat next door. Spraying the same product over and over can also help them build resistance. And total-release “bug bombs” don’t reach the hiding places at all, and can be a fire risk near a gas cooker.
4. They have food and water
Cockroaches don’t need much. Crumbs under the cooker, a greasy film behind the microwave, an open bin, a dripping tap or a wet sink overnight is enough to keep a colony going. As long as that supply is there, any survivors have what they need to build back up.
5. They’re coming in from next door
In flats and shared buildings, cockroaches move between units through shared walls, pipes, drains and corridors. You can clear your own kitchen completely and still get new ones from a neighbour’s. This is why treating a whole block, or at least the units next to yours, works much better than treating one flat at a time.
6. You’re bringing them in
Cockroaches and their egg capsules travel in cardboard boxes, grocery bags, crates of soda and second-hand appliances. A box from the shop or market that has been sitting in a storeroom can carry a whole new start into your kitchen.
What actually works
Getting rid of cockroaches for good usually takes a combination of things, done properly and repeated.
- Baits instead of sprays. Cockroach gel baits are placed in small dots in the places they hide. Cockroaches eat the bait, go back to their hiding place, and die there, and others that feed on them can die too. This reaches the ones you never see.
- Treating the hiding places, not the open floor: hinges, cabinet corners, under the sink, behind and under appliances, and cracks along the counters and skirting boards.
- Repeat treatment. Because eggs hatch weeks later, one visit is rarely enough. Expect follow-up treatment every few weeks until you’ve gone about a month without seeing any.
- Monitoring. Sticky traps placed under the sink and behind the fridge show whether the numbers are dropping, and where the remaining ones are.
This is where a professional pest control company makes the difference. When you’re comparing companies, ask what they’ll use, where they’ll treat, and whether follow-up visits are included.
How to keep cockroaches from coming back
Treatment clears them. These habits stop the next lot from settling in:
- Clean up every night. Wipe the counters and cooker, sweep the floor and don’t leave dirty dishes in the sink overnight.
- Clean behind and under the cooker, fridge and microwave every few weeks. That’s where grease and crumbs build up.
- Store food in sealed containers, including sugar, flour, unga, rice and pet food.
- Take the rubbish out daily and keep a lid on the bin.
- Fix leaking taps and pipes, and dry the sink at night.
- Seal cracks along counters, skirting boards and around pipes with silicone.
- Cover drains at night if large cockroaches are coming up from them.
- Unpack shopping and deliveries outside the kitchen, check the boxes, and get rid of cardboard quickly.
Are cockroaches a health risk?
Yes, mainly in two ways. Cockroach droppings, shed skins and dead bodies contain allergens that can trigger asthma, which matters a lot in homes with young children. They can also contaminate food and surfaces as they move between drains, bins and your kitchen counters. That’s reason enough not to just live with them.
Done with cockroaches?
AVA Fumigation & Pest Control treats cockroaches in homes, restaurants, offices and hospitals across Nairobi and the rest of Kenya. We find where they’re hiding before we treat, and our pest control treatments come with a 3-month warranty. The consultation is free.
Call or WhatsApp us on +254 728 296239, or request a free quote.