In 1952, Mountain Meadow Mushroom Farms, Inc. started as a white button mushroom grower with only 6 growing houses. In 1996, 27 growing houses were built making MMM Farms the largest white mushroom grower in Southern California. By 2021, the farm added exotic mushroom varieties like crimini, portabello, shiitake, oyster, lion's mane, king trumpet, maitake, beech, pioppino, reishi, turkey tail, and cordycep.