How Do I Grow Shiitake Mushrooms on Logs or Blocks?

Shiitake is one of the most popular culinary mushrooms in the world, and growing your own delivers a flavour that store-bought versions simply cannot match. The process takes more patience than oyster mushrooms, but the rewards, both in taste and in multiple years of harvests from a single log, make it well worthwhile.

Log vs. Sawdust Block: Which Method Is Right for You?

Log cultivation is the traditional approach and produces the highest-quality mushrooms, with thick, firm caps and deep umami flavour. Use freshly cut hardwood logs, ideally oak, maple, or beech, between 10 and 15 cm in diameter and about 1 metre long. Logs take 6 to 12 months to colonise fully before fruiting begins, but once established they produce for four to seven years. Sawdust blocks colonise in eight to twelve weeks and fruit much sooner, making them better for growers who want quicker results. Block mushrooms are excellent but slightly less dense than log-grown ones.

Inoculation and Colonisation

For logs, drill holes in a diamond pattern every 15 cm along the log and hammer in plug spawn or inject grain spawn, then seal holes with wax to prevent drying out and keep competitors out. Store logs in a shaded, humid spot, such as a forest floor or a covered area with regular watering. For sawdust blocks, mix sterilised hardwood sawdust with wheat bran, add spawn, seal the bag, and store at 18 to 24 °C. The block is ready when it has turned uniformly white and firm.

Cold Shocking to Trigger Fruiting

Shiitake needs a temperature shock to begin producing mushrooms. For logs, this means soaking in cold water for 12 to 24 hours, then returning to a warm location. For blocks, a drop in ambient temperature combined with increased airflow is usually sufficient. After shocking, expect pins to emerge within seven to fourteen days. Repeat the soaking process every eight to twelve weeks for logs, and after each flush for blocks.

Harvest Timing and Yield Expectations

Harvest shiitake just before or as the veil beneath the cap breaks. The caps should still be slightly curled under at the edges. Fully open caps are still edible but have shorter shelf life. Twist and pull individual mushrooms cleanly. A mature log can produce 500 g to 1 kg of mushrooms per flush across multiple flushes each year. Yields decline gradually after year four and the log eventually breaks down into rich compost.