How to Grow Mushrooms on an Outside Log


In the wild, mushrooms grow in moist, shady environments, often in leaf mold or around the roots of a tree. Some mushrooms grow on logs. You can replicate this wild environment by planting mushroom spore in logs in your backyard. The mushrooms draw nutrition from the cellulose in the wood. According to the United States Forest Services, you can grow shiitake (Lintinula edodis), maitake (Grifola frondosa), oyster (Pleurotus sp) and lion's mane (Hericium erinaceus) by this method.

Step 1

Spread the logs flat on the ground in the area where you will keep them while your mushrooms are growing. The US Forest Service recommends logs 2 to 4 feet long, as these will be easiest to handle.

Step 2

Drill holes 6 inches apart in the logs and 1 inch deep, in rows 2 inches apart. Stagger the holes in the rows, so that they're arranged in a diamond pattern. Your rows of holes should encircle the log.

Step 3

Hammer the mushroom spawn dowels into the holes with the wooden mallet. Tap gently until the dowel is securely seated. If you purchased loose sawdust inoculated with mushroom spawn, pack the spawn in the holes by hand. You can also use an injector designed specially for inoculating spawn in logs.

Step 4

Melt the wax in the pot on the camping stove. Fill the turkey baster with the wax, and cover each hole with the wax. Don't worry if wax drips down the log. Your aim is to seal the end of the hole.

Step 5

Stack the logs to allow for air circulation. You can lay a row of logs 6 inches apart on the ground and add rows of logs on top, alternating the direction of each row, or you can lean the logs on end, tepee style.

Step 6

Monitor the ends of the logs for moisture content. You can use a special probe to measure the moisture level, or cut a section from the end of the log and weigh it, then dry this section in the oven and weigh again. The difference between the wet and dried section indicates the moisture content. The optimum moisture level for mushroom production is 35 to 45 percent, according to the University of Missouri Center for Agroforestry. If the moisture level falls too low, wet the logs by pouring or sprinkling water over them to soak them thoroughly.

Step 7

Allow the logs to rest for a year, in order for the mushroom spawn to fully inoculate the logs.

Step 8

Immerse the logs in cool water for 20 hours after the inoculation period. You can carry the logs to a nearby stream or soak them in a water trough or even a child's wading pool. This water immersion encourages fruiting.

Step 9

Harvest mushrooms when the caps are about 70 percent open. The University of Missouri Center for Agroforestry recommends grasping the mushroom and twisting it from the log.

Step 10

Rest the log for 12 weeks, then submerge again to encourage a second harvest. You can repeat this process until the log falls apart or no longer produces satisfactorily.

Tips and Warnings

  • Avoid burning yourself with the hot wax.

Things You'll Need

  • Freshly cut hardwood logs, 3 to 8 inches diameter
  • Cordless drill
  • Drill bit the same diameter as the mushroom spawn
  • Mushroom spawn
  • Wooden mallet
  • Wax
  • Pot for melting wax
  • Camp stove
  • Metal turkey baster


  • USDA Forest Service: Farming Exotic Mushrooms
  • University of Missouri: Growing Shiitake Mushrooms

Who Can Help

  • Marin County Cooperative Extension: Growing Mushrooms in the Garden
Keywords: growing mushrooms, raising shiitakes, mushrooms in logs

About this Author

Cynthia Myers is the author of more than 40 novels and her nonfiction work has appeared in publications ranging from "Historic Traveler" to "Texas Highways" to "Medical Practice Management." She has a degree in economics from Sam Houston State University. Before turning to freelancing full time, Myers worked as a newspaper reporter, travel agent and medical clinic manager.