Does Soap Kill Cockroaches?

Cockroaches are one of the difficult pests to get rid of completely. A larger infestation of roaches in your home can be overwhelming and expensive to get rid of especially if you seek the service of an exterminator. But you can kill roaches with inexpensive DIY home remedies such as soap and water.

Also Read: Do Cockroaches Drown In Water?

Does soap kill roaches? Soap and water can be used to get rid of roaches at home. How does soap and water kill roaches? If you mix soap and water and spray it on the roaches, it kills them by blocking the outer protective layer of the roaches and also blocking their spiracles. This makes it difficult for the roaches to breathe leading to their death.

Soap alone may not kill the roaches but a mixture of soap and water does. Cockroaches tend to eat the soap since it contains fat which implies soap is not toxic to them. You have to mix water and soap and put in a spray bottle.

Does Soap Attract Roaches?

Yes soap attract roaches. Cockroaches eat soap since it has fat. This means soap can be food to the roaches especially when there is no food source. Soap is not toxic to the roaches. Bar soap in particular is made from ingredients such as oils and fats. Cockroaches will derive nutrients such as proteins and carbohydrates from soap. This forms the diet of a cockroach. It is probably the reason why roaches are in some cases found in the bathroom.

Do cockroaches Like Soap?

It is obvious from previous articles, that roaches will eat anything if there is no food available. Soap is no exception. The ordinary bar soap can be food to roaches when they are faced with starvation. Soap is made from items like fat and oil. This gives the soap a moisturizing effect on the skin, pleasant smell and other medicinal benefits.

Obviously, anything that has protein and carbohydrates becomes food to roaches. Soap has carbs which forms the desirable menu of a cockroach’s diet. Carbs helps the roaches to retain nutrients and boost male pheromone release for attracting mates.

When cockroaches are faced with starvation, the will turn on the soap usually in your bathroom or kitchen to survive.  Eating soap doesn’t cause any harm to the roaches.

Does Soap and Water Kill Cockroaches?

Yes, soap and water will kill cockroaches. But this is not 100% effective method to eliminate roaches in your home. But you can still achieve best results if you mix soap with water. Put the mixture in spray bottle and spray over a wider surface area where the roaches are likely to be seen crawling. Give it time for the water and soap to get into the cockroach’s spiracles.

According to a study published in Advances in Biological Science Research, when American cockroaches were sprayed with up to 5 sprays of soapy water from a bottle at 32% concentration, in just 24 hours more than half of the roaches were dead. This was more 50% of the roaches exposed to soapy in just 24 hours. A higher concentration of soapy water still produced this similar results. Liquid dish soap was also used and the results was equally effective.

Does Soap Kill Male Roaches Better Than Females?

The death rate in males and female roaches tend to differ from each other. For instance in a journal published by the Journal of Economic Entomology found out that a female German cockroach appear to be difficult to kill with soapy water solution in comparison to the male.

From scientific research, it has been proven that on average male roaches have shorter lifespans the female roaches –International Journal of Scientific Research

Do Cockroaches Die in Soap?

Laundry soap be it bar soap or liquid can kill roaches. Although soap in itself cannot get rid of the cockroaches. But you can use soap to get rid of the roaches. A mixture of soap and water can destroy the roaches’ protective outer coating and block their airwaves or spiracles. When cockroaches are unable to breathe after being exposed to soap, they will eventually die.

What Type of Soap Kills Roaches?

The two common types of soap that can kill roaches include both the liquid and bar soaps. The only difference between the two is their ingredients or additives.

A bar soap for instance has additives that are meant to soften the skin and at the same time give a pleasant smell. Here’s how to kill roaches with bar soap:

  • mix 1 cup of water
  • add ¼ cup of melted bar soap.
  • Shake well
  • put the mixture in a spray bottle
  • spray a wider surface area covered by the roaches

Note: the mixture of soapy water should be at 32% or more in concentration. This is to increase the intensity and effectiveness such that sprayed roaches will die within 24 hours.

While a bar soap is effective against roaches, the liquid soap may be the best. The additives in liquid soap tend to cut through heavy grease, kill bacteria and for this reason it is considered harsher.

Liquid soap is easy to use since you can easily mix with water and put in a spray bottle. Liquid soap has lesser fats or oils since it more chemically manufactured. Here’s how to use liquid soap:

  • 1 cup of water
  • 1 -2 teaspoon of liquid dish sap
  • Shake well
  • Put the mixture in a spray bottle
  • Use it generously on the areas infested with roaches.

Does Laundry Detergent Kill Cockroaches?

Laundry detergent works well against roaches. Powdered laundry detergent mixed with borax is one of the DIY home remedy to kill roaches. You can mix the laundry detergent with water to make a spray. Shake well and spray on the roaches directly. The detergent when sprayed on the roaches it penetrates into the spiracles preventing air from entering in and out of the roaches’ respiratory system.

If you roaches are sprayed with liquid detergent or soapy water, the grease that protects the cuticle of the cockroaches is washed off. This also have an adverse effect on their body since the roaches will lose body water and desiccate.

Does Soapy Water Kill Cockroaches Instantly?

Soapy water doesn’t kill cockroaches instantly. If you spray cockroaches to let’s say 5 sprays of soapy water from a spray bottle of 32% concentration, more than 50% of cockroaches sprayed will die within 24 hours.

Although the mortality rate for male and female tend to differ slightly from each other but within 24 hours nearly more than half of the roaches sprayed will be dead. Soapy water tend to harm a cockroach’s protective outer coating making it hard for the cockroach to maintain hydration and remove water off its body.

Soapy water is harsh such that it suffocates the cockroaches to death. Remember roaches have a unique respiratory system. Instead of lungs, they have spiracles. When cockroaches are sprayed with soapy solution, it blocks the breathing airwaves of the roaches. This means that the roaches will have a difficulty in opening and closing of their spiracle. In the end, the cockroaches will suffocate to death.  

How Does Soap Kill Roaches?

Soap and water mixture is a proven method to kill roaches, it is no longer a myth but a fact. But how does a soap kill cockroaches? Here’s how soap work against roaches:

 Soap Suffocates Cockroaches

This is one of the reason why soap is effective in killing roaches. When roaches are sprayed with soapy water, it blocks their breathing passages. Unlike most creatures that use lungs to breath, roaches have spiracles or respiratory system along their bodies. Soap blocks air to be taken in and out of their bodies since the spiracles are blocked.

Soap solution tend to coat and block the air passages making it difficult for the roaches to open or close their spiracles. They will instead breathe in soap which chock them to death.

Soap Destroys Cockroaches’ Protective Coating

Cockroaches like most insects tend to produce an oily and waxy outer coating. This is to cover and protect them against bodily harm. It also helps the roaches to repel water of their body and maintain hydration.

Soapy water is harsh to this protective waxy layer. If you spray roaches with soapy water, it removes their outer protective coating making them roaches vulnerable and in danger of dying due to excessive water loss and damage to their body.

How To Kill A Roach With Soap

It is now obvious soap is effective in killing roaches. You only need to make the soapy water highly concentrated to work against the cockroaches. Here’s how to kill a roach with soap.

  • Mix 1 cup of water with 1-2 teaspoon of liquid soap
  • Put the mixture in a spray bottle
  • Shake well the mixture
  • Spray the mixture generously on the roaches
  • Make sure to cover a wider surface area to kill as many roaches as possible
  • Spread regularly to achieve best results.

Is Soap A Good Roach Killer Method?

Soap and water is one of the simple DIY home remedy to get rid of roaches. It is inexpensive but it doesn’t work instantly.

Why is soap a good way to get rid of roaches in your home. Here are the reasons:

  • It is non-toxic– soap in small quantities is not harmful to animals and people. It is safe if you have pets or kids.
  • Cheap – using soap and water is an inexpensive method to kill roaches. Soap is readily available. You will have to spend less probably less than a dollar compared to buying insecticides or hiring an exterminator.

While soap may have advantages discussed above, but it also has its limitations or demerits. Here are some of them:

  • Not 100% effective

Although soap and water can help get rid of roaches, it has been shown that different cockroaches species react to the soap differently. Compared to commercial pesticides, soap and water is less effective.

  • Soap only Handles a Small Infestation

Soap and water is only effective when dealing with a few roaches. But dealing with a cockroach requires a more effective method.

  • Soap Requires Your Presence

To effectively get rid of roaches with soap and water, you may be forced to be there in person. This means you have to wait when the roaches come out at night. This means you may not kill the roaches the way you expect. You cannot also leave the soap overnight, since the roaches will eat the soap if they don’t find any food available at that particular moment.


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