| Sulfur is the natural enemy of powdery mildew. Garlic contains sulfur, and lots of it. In fact, a common home remedy for powdery mildew is to crush a few cloves of garlic in a gallon of water to make a spray for the affected plants. I don't believe your garlic will be bothered by powdery mildew. |
Here is a link that might be useful: Keeping ahead of powdery mildew