Mushroom Soil is the soil that is a byproduct of Mushroom Soil of the Mushroom factories, a dark nitrogen-rich soil used in a garden, planting beds, and new lawn development. Mushroom soil is typically used as a natural fertilizer that replenishes all the nutrients that crops, flowers, and grass require. FS Bulk Materials provides Mushroom Soil for customers and is available for Pick-up or Delivery.