Avoid this by using home remedies that will not damage your plants or your garden’s air quality.
Rubbing Alcohol and Cinnamon
Cinnamon is a fungicide that attacks the powdery mildew in your garden without damaging your plants. You can also use it inside your home to remove mild powdery mildew growth. Add 2 tsp. of ground cinnamon to a pint of rubbing alcohol in as spray bottle. Shake the mixture to combine and let it stand overnight. Filter the solution through a coffee filter or cheesecloth to take out any lumps of cinnamon that might clog the spray bottle. Spray the solution directly on powdery mildew as needed.
Milk
Milk is a natural fungicide that will attack powdery mildew growth on plants. The milk will also make your plant's leaves shine. To use milk, mix no more than 3 parts milk with 9 parts water and spray it on the plants leaves to cover the powdery mildew growth as needed.
Dishwashing Detergent
Mild liquid dishwashing detergent will kill powdery mildew inside your home as well as in your garden. Mix 1 tbsp. of the detergent with 3 tbsp. of cooking oil. Add 1 tbsp. of baking soda. Pour the concentrated solution into 1 gallon of water and spray it on the powdery mildew every three days. Do not spray more often as you run the risk of damaging your plants as well. Use detergent that does not contain bleach or fragrances.