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

A few years ago, it was standard practice to give a significant amount of water in the first few days after casing. It was common to see people aiming for maximum watering, with 35 liters per square meter being standard and 40 liters considered even better. The goal was to adjust the moisture in the phase 3 compost, with the aim of reaching a moisture level of 72% or more.

Today, clients around the world are seeking better-quality mushrooms. Every grower aspires to cultivate the perfect mushroom.

The Perfect Mushroom

The ideal mushroom looks the same everywhere in the world:

• It has a good color and shape
• It is heavy and dense
• It has a long shelf life
• For us as growers, it must be financially viable, producing a high yield with minimal costs

This type of mushroom grows only when all conditions are in balance:

• The compost contains all essential nutrients that are accessible to the mushrooms.
• The water content in the compost is available to the mushrooms, but not in excess. If the mushrooms have to work a little to access this water, it will produce a stronger mushroom.
• Compost activity should be low during picking. If the compost is too active, water may be forced into the mushroom during picking. This can be managed by adjusting the filling weight or compressing the compost.
• The climate in the growing room should be natural; this means avoiding extremes in air temperature, CO2 levels, or fan speed.
  
  

Compost Filling Weight

Many farms worldwide still prefer to fill a large amount of compost per square meter. It’s often believed that more compost produces more mushrooms, which is true. However, this added compost must also be managed carefully. Typically, if you increase compost volume, you’ll need to employ extreme climate controls to manage compost activity, such as high fan speed or low air temperature. During the first flush, this compost activity often makes it difficult to maintain a gentle climate. A gentle climate in the first flush is crucial for producing high-quality mushrooms. It doesn’t help to have an excellent third flush if the majority of your first-flush mushrooms are damaged due to extreme climate adjustments for compost activity. This increased activity dries out your compost and casing, causing issues for the second and third flushes.

Watering and Compost Activity

After filling phase 3 compost, the mycelium is damaged and needs time to recover. Adding too much water in the first two days after filling halts mycelium growth. The mycelium cannot spread over the compost because water sits on the outside of the compost. In these cases, high compost activity occurs because the mycelium is competing with the water. It is much better to allow the mycelium to regrow (recover) for two days after filling, only adding small amounts of water to keep the casing moist.

Watering on Different Types of Compost

A watering schedule depends on various factors:

• When the compost is not fully colonized with mycelium and remains active, wait before watering to allow mycelium to incubate. Once the mycelium starts growing into the casing, you can gradually increase watering.
• When the compost has a long or coarse structure, you can begin watering earlier. The loose structure allows excess water to drain to the bottom of the compost.
• When you have a short or soft compost, be especially careful with watering during the first two days. This type of compost acts like a sponge, absorbing water in its top layer. This prevents the mycelium from regrowing in the upper layer, creating a weak connection between the compost and casing.
• If you fill with warm or highly active compost, it’s better to minimize watering on the casing, adding just enough to keep it moist. Some growers add large amounts of water to cool down the compost, but this only halts mycelium regrowth and increases activity.