Homemade roach spray can be made with liquid soap, water, and cypress or peppermint essential oil. Borax and baking soda may also be added to kill roaches in the nest.
Homemade roach spray typically contains 1 teaspoon of liquid dish detergent and 1 cup of water. Spray consisting only of dish detergent and water is effective only when sprayed directly on roaches. Borax or baking soda may be added to the spray to create a mixture that effectively kills roaches where they live, in the nest.
To make a spray containing borax, mix 1 part borax to 10 parts hot water, then add 1/2 teaspoon of liquid dish detergent. Mix the borax and hot water thoroughly to ensure the borax has dissolved, and spray as needed in areas where roaches are present. Alternatively, use baking soda instead of borax. The proportions remain the same.
Essential oils may be added to borax, soap or baking soda sprays to help deter roaches in homes with adjoining units, such as apartments or condos, or the essential oil may be mixed with water and used alone. Add 15 to 20 drops of therapeutic-grade cypress or peppermint essential oil per cup of homemade spray to repel roaches.