German cockroaches are one of the most resilient pests found in homes across the UK. Thankfully they are not that common here, but if you have an infestation it can be very difficult to resolve. Their rapid reproduction and ability to hide in the tiniest of spaces make them particularly troublesome. If you’ve spotted these dirty, unwelcome visitors in your home, it’s essential to take immediate action to prevent a full-blown infestation.
In this guide, we’ll walk you through how to identify German cockroaches, understand how they enter your home, and effectively get rid of them using a range of DIY methods.
What Does a German Cockroach Look Like?
Before you can tackle a cockroach problem, it’s important to know what you’re up against. German cockroaches are small, typically between 12-15mm in length, with a light brown or tan colour. One of their most distinguishing features is the two dark parallel stripes running from the back of their heads down to their wings. Unlike some other species, German cockroaches are not strong flyers, although they do have wings.
Below is an image of German cockroaches – an adult and a young nymph cockroach. As you can see, they vary in appearance depending on their age.
These pests are usually found in warm, humid environments near food, making kitchens and bathrooms prime locations. They tend to be nocturnal, so if you spot one during the day, it could indicate that you have a significant infestation. They only appear during the day when their population is very large and resources such as food and shelter are becoming more scarce.
How Do German Cockroaches Get into Your House?
German cockroaches are experts at sneaking into homes. They typically enter via cracks and crevices around doors, windows, and plumbing fixtures. These cockroaches can also hitch a ride in grocery bags, boxes, or even second-hand appliances.
Once inside, they gravitate towards areas with food and moisture, making kitchens, bathrooms, and laundry rooms ideal habitats.
A clean home is no guarantee against these pests, as they can survive on the smallest crumbs or even by eating paper. If they don’t have food, they will happily eat each other, or each other’s faeces. Because of this, it’s pretty much impossible to starve out German cockroaches, and heavy-handed action is always needed to control them.
How to Get Rid of German Cockroaches
If you’ve confirmed the presence of German cockroaches in your home or business, swift and decisive action is necessary. Here are several DIY methods to use in combination to help you beat the infestation:
Blocking entry
You should take steps to prevent German cockroaches entering your home. This means ensuring that doors all have good seals around them. If you live in an apartment they can travel from one unit to the next through the common area, slipping under doors that are not sealed very well. You might choose to buy a new door and door frame with good seals if you think this is how they are getting in.
They also travel through shared cavity walls, using holes for pipes and cables as their corridor. Seal up all such holes. Many holes like these will be behind kitchen units, so it could mean a major piece of work to reach these for sealing. It might be prudent to ensure adjoining units in the same building get treated at the same time, if that’s easier.
Since the UK is quite cold, they don’t normally come in from outside. They are an indoor pest, so they’ll invade from another indoor location, such as neighbouring dwelling, or if they are carried into the property accidentally.
Pesticide Sprays
Pesticide sprays are a common and effective method for killing cockroaches. These sprays are available in most hardware stores and are easy to apply. Aerosol sprays, like this Rentokill one, are excellent for killing visible cockroaches, and they can be used to gas those hidden deep in cracks or crevices. For best results, spray directly onto roaches when you see them to kill them stone dead instantly.
Never be tempted to just squash cockroaches because they have all sorts of bacteria that you’ll end up spreading through the house on the sole of your shoe.
In addition you should use a bottle of this Entopest or other long lasting hand-pump spray to treat all the skirting boards, architraves and door frames in the property. Cockroaches like living in cracks in wood so the pesticide will kill them or at least force them to evacuate so you can spray them directly.
Be sure to treat the building’s common areas if you live in an apartment, so as to discourage them from coming near your door.
It’s best to treat all around doors, skirting boards, and architraves once every couple of months with NOPE. This limits the cockroaches’ ease of travelling around your home as they won’t enjoy walking on sprayed areas.
Insecticidal floor cleaner
To further limit cockroaches’ ability to spread, you can start using insecticidal floor cleaners when you mop the floor. This leaves a residue, which cockroaches hate. Here’s a product you can use.
Using this floor cleaner in combination with spray, you will severely limit the cockroaches ability to move around, isolating them which makes the next steps of treatment easier….
Growth inhibitors
Growth inhibitors don’t kill the cockroaches but they stop the pest from developing and maturing. If they can’t mature, they can’t multiply, and will die out eventually. This is important because the cockroach’s main defence against hostility is rapid reproduction.
Unfortunately, it’s not easy to get pure IGR products over the counter in the UK, but the recommended Entopest spray contains IGR in its formula.
Spray this on all non-porous surfaces such as inside kitchen cabinets, on bins, painted skirting boards etc to put your cockroaches on a course of birth control. Always make sure to read product instructions and safety info, and to keep all pesticides well away from food, pets, children etc.
If you’ve been following along, you’ve now restricted the cockroaches’ ability to enter the property, and move around the home. You’ve also limited their ability to multiply using growth inhibitors. Now, it’s time to pick off the living population using baits and spray.
Morning hunting
As discussed earlier, you should spray them directly when you see them with Rentokill or Raid aerosol insecticide for ants and cockroaches. Be sure to keep a lookout for cockroaches first thing in the morning as they are often active then. Once they realise that you are awake they will often go into hiding. So, first thing in the morning you can catch them off guard by immediately going on a cockroach hunt nice and early, checking all the usual places in the kitchen and bathroom:
- Floors
- Walls
- Counter tops, including under electronics
- Cupboards
- Drawers
Poison Baits
Poison baits are an effective method for targeting cockroaches that remain hidden. The bait is usually mixed with a food source that attracts cockroaches. Once consumed, the poison works slowly, allowing the cockroach to return to its nest and spread the poison to others. This domino effect can significantly reduce the cockroach population over time. Place baits in areas where you’ve seen cockroach activity, but keep them out of reach of pets and children. Baits are best located along corners.
Key places for baits include:
- Corners of the inside of all kitchen/bathroom units
- Under kitchen/bathroom units (behind the kitchen kickboard)
- Under or behind the oven, fridge and other white goods
If you have kids or pets, then you can use poison that comes in a protective encasement to help prevent contact.
If using poison bait, never use a spray in the same place as the bait, because it will deter cockroaches from going near the bait!
Cockroach Sticky Traps
Sticky traps can be another powerful tool in your cockroach-fighting arsenal if you choose the right traps. The way they work is, the traps capture cockroaches as they walk over the sticky surface trying to reach the bait. The sticky surface prevents them from escaping.
The best sticky trap to use is the Hoy Hoy trap. This trap uses bone meal bait. German Cockroaches go absolutely bonkers for it. We’ve previously caught over a 100 German cockroaches in a single Hoy Hoy trap. Since traps are non-toxic it makes them ideal for homes with kids or pets and can be used as an alternative to poisons.
If using traps, never use a spray in the same place as the spray will deter cockroaches from going near the trap.
The best places to put traps are the same locations you would put poison bait as discussed above.
When to Seek Professional Help
While DIY methods can be effective in eradicating the population, German cockroaches are notoriously difficult to get rid completely, especially if this is your first time going to war with these critters .
If you’ve already tried these methods and are still seeing signs of cockroaches, it may be time to call in professional pest control services. Professionals have tried and tested methods and processes which are likely to be more effective than a first-time DIY strategy.
If you have a cockroach problem in a business, then reach out to Merlin as we specialise in discreet commercial pest control, and we understand the nuances around the use of chemicals by each industry, to ensure your business remains compliant with industry regs. We can also work at night so as not to alert staff of customers.
