A great alternative to chemical repellents and pesticides are eucalyptus oils. This essential oil has a strong and unfamiliar smell, which ants and gnats will try to avoid, thinking it's a sign of danger. SF Gate suggests making a repellent spray by adding 1/4 teaspoon of eucalyptus oil to one cup of water, shaking the solution, then spraying it on plants you want to protect from insects. Reapply every three days. To eradicate scale insects like aphids and mites, combine 1 teaspoon of eucalyptus oil, 1/2 teaspoon of liquid hand dish detergent and 2 cups of water instead.
RELATED: 5 Homemade Hand Sanitizers