GreenCure is a potassium bicarbonate-based fungicide used to control powdery mildew, black spot and other common plant diseases. GreenCure is recommended as a foliar treatment for more than 85 different plant varieties including vegetables, trees, ornamentals and houseplants. One tablespoon of powdered GreenCure to one gallon of water will cover approximately 450 square feet. GreenCure is also registered "for organic production" by the USDA's National Organic Program (NOP).