| Here's a simple formula for a safe spray to control mildew, once it gets started, developed by chemist and rose expert and author Thomas Cairns: Baking Soda Cure To make a spray to cure powdery mildew, add the following to a cup of water: 1 ½ tablespoons baking soda 1 tablespoon canola oil 1 tablespoon insecticidal soap After all these ingredients have been added to the cup of water, add 1 tablespoon vinegar, then enough additional water to make 1 gallon of solution that can be sprayed on foliage. Do not use when daytime temperatures go over 85 degrees; it may burn foliage. |