We’ve had it every year, but I never knew exactly what it was. I just called it the end of the season. So I am very disturbed that it hit us hard in the third week of August. The zucchini plants are covered with it and the spaghetti squash looks pretty unhappy too. Time for some serious research.
It turns out that powdery mildew loves hot, sunny weather, especially if you have happened to spray water on the leaves. Heavy dew doesn’t help either. Since our dry spell meant lots of hand watering, and the nights were dewishly cold, we have an epidemic on our hands.
I’m a believer in letting nature take its course, to a degree. If you have aphids, the ladybugs will show up. If you have voles, eventually a heron or a hawk will arrive. I’m also a big supporter of our organic gardening policy. However, losing our zucchini production in August is not acceptable. I had to find an organic solution, and I did – 1 teaspoon baking soda dissolved in 1 quart of water. We spent an hour cutting away the worst of the diseased leaves and spraying the mixture on the healthy ones. Baking soda doesn’t cure powdery mildew, but is supposed to create an inhospitable environment for the fungus, preventing it from spreading.
I hope we saved our squash crop.