To make your own insecticidal soap, you need dish soap or detergent, warm water and peppermint oil. Measure out 2 cups of warm water, 1 teaspoon of dish soap and a few drops of peppermint oil into a container. Mix the solution thoroughly. You can use castile soap or detergent instead of dish soap. If you use detergent, limit the amount used to prevent harming any plants. Although peppermint oil is not essential to the soap mixture, ants dislike the smell, and it tends to repel them.
Pour the soap and peppermint solution into a container for easy dispersal. A spray bottle works well.
Apply the soap and peppermint solution to any area where you have ant problems. Spray the infested areas as soon as possible so that the solution is still warm at the time of application. These infestation sites can be indoors or outdoors. Repeat application on a daily basis until the ant infestation is eradicated.