Powdery mildew can make a perfectly respectable garden plant look as though someone dusted it with flour. The good news: gardeners do not automatically need to ban every mildew-spotted leaf from the compost pile, but the answer depends heavily on how hot and active that pile gets.
A casual backyard heap that slowly decomposes presents a different situation from a well-managed hot compost pile. Knowing that distinction can keep a gardener from either wasting perfectly compostable plant material or accidentally giving plant disease a cozy little vacation in the garden.
