Does anyone have a recipe using Potassium bicarbonate (KHCO3) for control of sooty blotch and other garden fungus?
Recipe Using Potassium Bicarbonate (KHCO3) for Sooty Blotch Control
The following article addresses powdery mildew on roses, but the author's view on recipes is well stated: https://www.gardeningknowhow.com/ornamental/flowers/roses/roses-powdery-mildew.htm
There are hundreds, if not thousands of recipes online. As with all products, test a small area first before applying to an entire group of plants.