Minecraft wiki entry for Mushroom_farming, associated text: The basic of huge mushroom farming involves a 7x7x8 space and suitable ground. If you are outdoors, you can plant the mushroom using podzol, mycelium, or nylium. In the overworld, podzol is more easily available. To make podzol, plant a giant spruce tree with four saplings, and wait for it to grow. When it grows up, chop the tree down and use the newly formed podzol to plant a mushroom and bone meal it up. Planting consumes the underlying block, so you will need to occasionally regenerate by planting giant spruce again. (Mycelium can spread to the dirt, so no manual work is required.)