How to Grow Shiitake Mushrooms
Full Cultivation Guide

Phase 1: Arrival & Assessment

Upon arrival, handle the substrate blocks with care to avoid damaging the mycelial structure.

• Inspection
  Blocks should be firm with a popcorn-like surface texture (browning).
  If blocks are delivered only colonized, an extra incubation period of minimum 10 weeks is required
• Storage
  If not inducing immediately, store blocks in a cool area (2-4°C) to pause development.

Phase 2: Induction (Shocking)

Shiitake requires a specific trigger to shift from vegetative growth to fruiting.

• Remove Packaging
  Carefully strip the plastic bag entirely from the block.
• Cold Shock (Optional but Recommended)
  Submerge the blocks in cold water (approx. 10-12°C) for 6-12 hours.
  This mimics a natural rainfall event and heavy temperature drop.
  Note: If blocks are fresh and moist, a simple temperature drop in the growing room (to 12-15°C for 24 hours) may suffice.
• Placement
  Arranging blocks on shelving with adequate spacing (approx. 10 cm between blocks) to allow airflow.

Phase 3: Fruiting Development

Once pins (primordia) appear, climate control is paramount.

• Humidity
  Maintain RH at 90-93% during pinning.
  As the caps expand, gradually lower RH to 85%.
  This prevents bacterial blotch and ensures a firm cap texture.
• Ventilation (CO₂₎
  Shiitake is sensitive to high CO2.
  Keep levels below 900 ppm. “Leggy” mushrooms (long stems, small caps) indicate insufficient fresh air.
• Watering
  Mist lightly if the block surface appears dry.
  Avoid direct heavy watering on the mushroom caps, especially near harvest.

Phase 4: Harvest

Harvest timing determines the shelf-life and grade of your product.

• The “Veil” Rule
  Harvest when the veil beneath the cap has broken, but the cap margin is still slightly curled under (approx. 70-80% open).
• Technique
  Shiitake mushrooms are generally harvested with a knife instead of twisting.
  Avoid tearing the substrate, as this can damage the mycelium needed for the second flush.
• Post-Harvest
  Clean any broken stem fragments from the block surface immediately to prevent contamination.

Phase 5: Second Flush Management

CNC substrates are designed to yield multiple flushes if sufficient growing space is available.

• Resting Period
  After the first harvest, allow the blocks to “rest” for 14-21 days.
  Lower humidity to 60-70% to let the skin of the block harden slightly.
• Re-Hydration
  After 14-21 days slightly water the blocks and reduce temperature to generate a cold shock.
  This will start second flush
• Restart
  Return the blocks to the fruiting room and resume Phase 3 conditions.

Disclaimer
These instructions are general guidelines for CNC substrates.
Optimal parameters may drastically vary depending on your specific growing facility design and environment.