Mycelium Growth in Casing Soil ( back to basics)

We are observing that the amount of mycelium in the casing soil often leaves much to be desired. Ideally, thick mycelium strands should grow from the bottom to the top of the casing soil, while leaving enough casing soil not yet overgrown with mycelium. This remaining casing soil serves as a water buffer for the compost and mushrooms.

It's crucial to remember that this water buffer also determines how long and how much you can evaporate in the growing room before the casing soil dries out. If the casing soil dries out, you will need to water, even if it's not ideal for the mushroom quality. Therefore, it is important to pay close attention to the mycelium growth in the casing soil.

If there is structurally too much mycelium in the casing soil, a few adjustments can improve the situation. One option is to start ventilating earlier, although this means the mycelium may not reach the surface as much as usual. You can also adjust the watering schedule.

Once the mycelium starts growing from the top layer of compost and the casing material, it is essential to keep the casing soil well-moisturized. Each watering essentially stops the mycelium; weak mycelium struggles with this and can barely continue developing, whereas strong mycelium has fewer issues and continues to grow. In this way, you encourage more strong mycelium and reduce the amount of mycelium in the casing soil.

Our mushroom strains tend to form pins quite spontaneously, so many growers are ventilating extremely slowly. While this isn't necessarily a problem, it's important to realize that as long as the compost temperature is above 23°C, the mycelium will keep growing in the casing soil. Therefore, you should start ventilating earlier or increase circulation to bring the compost temperature below 23°C quickly. Once the compost temperature reaches 23°C, you can reduce circulation and control the number of pins by adjusting the air temperature.

I believe that with this method, you can control the amount of mycelium to some extent without leading to too many pins or a lack of distribution in the first flush. You might also consider using slightly heavier casing soil.

Slightly drier casing soil offers more certainty in terms of mycelium growth. Also, pay attention to covering. Avoid running the pinning axis and leveler too quickly to prevent structural damage. The mixing of the casing should be adequate, but more speed is unnecessary for the pinning axis.

Written by: Jeroen van Lier | Total Mushroom Service