Lawn mushrooms are a sign that your yard is too wet. If these fungi appear after a heavy rain, they will usually go away on their own. However, you see them regularly, you'll need to find a way to dry out your lawn. The first step is to cut back your watering routine. If that doesn't help, try improving drainage with the use of a lawn aerator. Toadstools still haunting your lawn? Consider trimming overhead tree branches to let in sunlight and banish mushrooms.