How much peppermint oil to water ratio for spider spray?

A common peppermint oil to water ratio for a spider repellent spray is 1 teaspoon of peppermint oil per cup of water. You can also add a few drops of dish soap to help emulsify the oil in the water. Shake the mixture well before use and spray in areas where Spiders are likely to enter or hide. Always test a small area first to ensure the mixture doesn’t damage surfaces.