How to Grow Mini Oyster Mushrooms
Full Fruiting Guide

Phase 1: Preparation & Opening

For Mini Oysters, the goal is to trigger a high density of pins so the energy of the block is distributed across many small caps rather than a few large ones.

• Placement
  Place blocks on shelves vertically or horizontally.
• The “Precision Slit” Method
  Fold the excess plastic top down tightly and tape it to the block to eliminate air pockets.
  Make 3 to 5 smaller horizontal slits (approx. 3 cm) distributed around the sides of the block.

Why? More frequent, smaller openings encourage the block to produce several smaller clusters.
By restricting the air to smaller slits, we increase the internal pressure, leading to a “thicker” pin set which is easier to manage for mini-scale harvesting.

Phase 2: Induction & Pinning

Mini Oysters prefer cooler, stable conditions compared to their tropical Pink and Yellow cousins.

• Temperature
  Maintain a fruiting room temperature between 15°C and 18°C.
  This cooler range slows down the metabolism just enough to allow the pins to develop deep, rich colors (blue-grey to charcoal) and firm flesh.
• Humidity
  Maintain RH at 95% during the pinning stage.
• The “Pin Blanket”
  Within 3–5 days, a dense “carpet” of dark pins will emerge from the slits.
  It is vital at this stage to avoid high-velocity air directly hitting the pins, which can cause “capping”—where the pins dry out and stop growing.

Phase 3: Development (The “Shape Control” Phase)

Because we want “Mini” caps, the development phase is much shorter than standard Oyster production.

• CO2 Management
  Keep CO2 levels between 600 and 900 ppm.
  Note:
  If CO2 is too low, the caps will expand too quickly.
  If CO2  is too high, you will get long, “spaghetti” stems.
• The Goal
  You are looking for a short, thick stem with a cap that is just beginning to transition from a button to a shelf.
• Light
  Provide 1000 lux of light.
  Blue/Grey pigments in Mini Oysters are highly light-dependent; low light will result in pale, unappealing beige mushrooms.

Phase 4: Harvest (The “Petite” Timing)

The harvest timing is the most critical step in defining a “Mini” Oyster.

• When to Harvest
  Harvest when the caps are roughly the size of a thumb-nail (1–2 cm in diameter).
  The caps should still be “down-turned” and thick.
  If the cap begins to flatten out or thin at the edges, it is no longer a “Mini” Oyster and has transitioned into a standard Oyster.
• Technique
  Use a sharp knife to cut the entire cluster cleanly away from the block.
• Plating Aesthetic
  Chefs prefer Mini Oysters in clusters or as individual “buttons.”
  If harvesting for individual caps, use small scissors to snip the caps away from the central core.
• Storage
  Mini Oysters are remarkably resilient. Cool to 2–4°C immediately.
  Because of their small size and lower surface area relative to their density, they hold their quality in the cold chain longer than Pink or Yellow Oysters.

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