Boom times for gourmet mushroom growers. In recent years, demand for gourmet mushrooms has skyrocketed, creating opportunity for new growers. The most profitable culinary mushrooms are shiitake and oyster mushrooms. Both oyster and shiitake are easy to grow and can be produced on "waste" products like sawdust or straw. They are quick to grow to maturity - about 6-8 weeks from start to harvest. Best of...