Pesky Little Critters

The Science Behind Soapy Water’s Effectiveness in Killing Earwigs

Updated: March 30, 2023

Earwigs are a common garden pest that can cause significant damage to plants. One of the most effective and natural ways to get rid of them is by using soapy water. But how does soapy water kill earwigs? In this article, we will explore the science behind it.

How Does Soapy Water Work?

Soapy water works by disrupting the surface tension of water. Water molecules are attracted to each other, creating a surface tension that allows insects such as earwigs to walk on water without sinking. However, when soap is added to water, it reduces the surface tension, making it difficult for insects to stay afloat.

When earwigs come into contact with soapy water, they get coated in the solution, which clogs their respiratory system. Earwigs breathe through small tubes called spiracles, which they use to take in air. The soap in the water covers these spiracles and suffocates the earwig.

Why Is Soapy Water Effective Against Earwigs?

Earwigs have a waxy coating on their exoskeleton that helps them retain moisture. However, this same coating also makes it difficult for them to absorb water. Soapy water breaks down this waxy coating, making it easier for the earwig to absorb water and leading to dehydration.

In addition, soap has a drying effect on insects. When an earwig comes into contact with soapy water, it loses moisture rapidly, leading to death.

How to Use Soapy Water Against Earwigs

To use soapy water against earwigs, follow these steps:

  1. Fill a spray bottle with warm water and add a few drops of dish soap.
  2. Shake the bottle well to mix the soap and water.
  3. Spray the solution directly onto the earwigs or onto areas where they are likely to hide, such as under rocks or in crevices.
  4. Repeat the process as needed until the earwigs are gone.


Is soapy water safe for plants?

Soapy water is generally safe for plants, but it’s important to use it in moderation. Too much soap can harm plants by stripping away their natural oils and interfering with photosynthesis. Use a mild dish soap and dilute it with plenty of water to avoid damaging your plants.

Will soapy water harm beneficial insects?

Soapy water can harm beneficial insects, so it’s important to use it sparingly and only on areas where earwigs are a problem. Be sure to avoid spraying the solution directly on bees, ladybugs, and other beneficial insects.

How often should I use soapy water against earwigs?

You should use soapy water as often as needed to get rid of earwigs. If you have a severe infestation, you may need to spray every few days until the problem is under control. Once the earwigs are gone, you can reduce the frequency of sprays.

Are there any other natural ways to get rid of earwigs?

Yes, there are several natural ways to get rid of earwigs. You can use diatomaceous earth, which is a powdery substance that dehydrates insects. You can also set up traps using rolled-up newspapers or cardboard tubes filled with straw or hay. Earwigs will crawl into the tubes to hide, and you can dispose of them in the morning.


Soapy water is an effective and natural way to get rid of earwigs. By disrupting the surface tension of water and suffocating the earwig, it provides a simple and safe solution for gardeners who want to protect their plants from these pests. Remember to use soapy water in moderation and avoid harming beneficial insects.