Using Baking Soda to Combat Powdery Mildew
I heard you could use baking soda to control powdery mildew. Is this true? If so, do you have the recommended rate?
Cornell University discovered baking soda was an effective control against powdery mildew. It has been used by gardeners on vine crops, roses, perennials and other edible and ornamental plants. Start by mixing 1 tablespoon of baking soda in a gallon of water. Add a teaspoon of insecticidal soap OR lightweight horticulture oil to act as a spread sticker for the solution. Spray the plants at first sign of the disease. Repeat every 7 to 10 days throughout the season.
Related
Upcoming Live Events
& Webinars
Jan. 28, 2026
FREE WEBINAR:
Past, Present & Future of Mitchell Park and its Conservatory, the Domes
Register here
Feb. 13 - 15, 2026
PBS Wisconsin
Garden & Green Living EXPO
Madison, WI
More information
Feb. 18, 2026
FREE WEBINAR:
Plants that Go the Distance
Register here
Feb. 25, 2026
FREE WEBINAR:
Flowering Houseplants
Register here
Mar. 5, 2026
FREE WEBINAR:
Start New Plants from Seeds, Cuttings and More
Register here
Mar. 11, 2026
FREE WEBINAR:
Save Money & Boost Your Growing Success with Bare Root Plants
Register here
Mar. 18, 2026
FREE WEBINAR:
Patio, Deck and Balcony Gardens
Register here
March 26, 2026
FREE WEBINAR:
Getting Started Growing Vegetable and Flower Gardens
Register here
WATCH ON-DEMAND WEBINARS
Learn More


