Mycelium Crust

Avoiding Mycelium Crust: Tips for Healthier Mushroom Yields 🍄

One of the most common issues faced by mushroom growers is the formation of a mycelium crust, which forms in the lower part of the casing soil (touching the compost) overly run with very fine mycelium between the compost and the casing layer. This crust acts as a barrier, blocking nutrient and water movement, which ultimately affects mushroom yield and quality. It can occur in the second or third flush and is usually linked to the compost quality, casing soil structure, and irrigation practices.

🛑 Why does this crust form?

• Poor casing soil structure

• Uneven or delayed watering

• The soil touching the compost ,too dry

• Entering the "venting" phase too early

• Extended dry periods within the casing layer

💡 How to prevent mycelium crust:

1. 💧 Do not delay watering. Regular, timely watering prevents dryness that leads to crusting.

2. 🪨 Ensure good casing soil structure. A porous, friable mix allows air and water to move freely.

3. 🌫️ Maintain constant moisture. The casing should stay evenly moist — not too dry, not too wet.

4. ⏳ Avoid early transition to the venting phase. Let the mycelium colonize gradually and evenly.

5. ♟️ Aim for “chessboard” mycelium growth. A healthy casing shows patches of white mycelium over dark casing soil, not a solid white layer.

🔎 Sometimes, the crust forms inside the casing layer — especially when it's left untattered for too long. This leads to weak pinning and poor mushroom formation.