Q: My overwintering chard has started to show a "white powdery" substance covering both front and backsidesΒ on some of the leaves. Photos are attached comparing normal and white powdery leaves on the chard plants. Any idea what this substance is and are the chard leaves still edible?
A: It looks like powdery mildew. Β Left alone it can kill the leaves. Β The organic solution is to spray it with a baking soda and water mixture. Β There are also conventional fungicides labeled for use on vegetables available if you are okay with that. The mildew washes off and cooking will take care of the fungus so the leaves should still be edible. Β Make sure your plants have enough room for air circulation to prevent this in the future.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Β Questions may be emailed to tucsongardensage@gmail.com
