Scaling of Mushrooms

We all know the cause of scales! Too much air movement and/or too dry air. However, the wrong solution is often chosen. This decision is linked to knowledge of the Mollier Diagram. During the first flush, what decision do you make as a mushroom grower? Do you increase or decrease the fan speed to prevent scales during the first flush?

Many of my clients say they reduce the fan speed. So what happens when you reduce the speed? Fewer cubic metres of air flow into the growing room to control the air temperature in the room. This means using colder inlet air  to control the room air temperature. However, the colder the air, the more condensation on the cooling coil, and sometimes even on the air duct in the growing room. This means that far more moisture condenses from the air. (Remember the example of the sponge, if you don’t know about the ‘sponge example’, sign up for one of the courses😊). The result is much drier air in the growing room. And it is this dry, cold air that causes a lot of scaling where it comes into contact with the mushrooms.

What can you do to prevent scales?

• Make sure you start the first flush with a compost temperature of between 19 and 20° C.
• Never lower the air temperature when the compost temperature is rising.
• Gradually increase the air temperature on the day after the compost temperature starts to rise in the first flush.
• Ensure the air inlet temperature, i.e the air in the air duct, does not drop below 10^oC, (preferably a little higher).
• Increase the fan speed in good time.

In addition, it’s advisable to hang perforated plastic film along the lower two beds in the aisles below the air ducts. Otherwise, there will be too much air movement at this spot. Hanging up this film prevents scales on the mushrooms here.

If you take these measures before and during the first flush, you will notice fewer problems during the first flush.

Mark den Ouden| Mushroom Blog