This simple spray is useful for fighting black spot on roses and other fungal diseases on all sorts of plants. It will also discourage many insects.

  • 1 teaspoon baking soda
  • 1 teaspoon vegetable oil
  • 1 teaspoon natural dish soap or liquid soap
  • 1 teaspoon vinegar

Dissolve the baking soda in about a cup of warm water, put it and the rest of the ingredients into a one-quart spray bottle, and top off with water. Remove badly damaged leaves first then spray lightly on all plant surfaces. Repeat once a week or after every rain. This spray will keep indefinitely at room temperature.