Air exchange for oyster mushrooms

The relationship between flow speed, air humidity and substrate humidity

For oyster mushrooms, it is important not only to choose the right fan, depending on the tonnage of the substrate. It is much more important to properly organize air exchange.

Of course, this is not news. I talk about this every chance I get.

But I am faced with the fact that not all mushroom growers understand the relationship between air circulation and the condition of the mushroom.

Unfortunately, at a low air flow rate, the oyster mushroom suffocates and pulls its stem even with optimal humidity and ppm CO2 levels.

EVEN when the instruments show normal humidity and ppm values ​​right next to the mushroom itself.

The fact is that mushrooms do not have such a perfect evaporation system as plants.

They do not have stomata that can open and close.

Therefore, for each type of mushroom there are optimal air humidity parameters. In this case, the mushrooms can evaporate moisture from their bodies so that the surface of the fruiting body remains moist, but does not become wet or dry. If the air humidity is insufficient, the mushroom evaporates more moisture from the cap.

The mass of each mushroom is greatly reduced and the cap will be dry.

But if the air humidity is optimal, and the air flow that blows over the mushroom is weak, then the cap cannot evaporate a sufficient amount of moisture from its fruiting body.

That is, a flow of air at a low speed cannot carry away its own moisture from the oyster mushroom and it reduces evaporation. Because of this, the mushroom becomes wet, the cap may bend and have a bizarre shape.

That is why:

  1. It is important that the air duct has cone-shaped cups and does not just have holes. The cone of the cup swirls the air flow, increasing it.
  2. Air velocity from the duct is important. It must be at least 7.5 m/sec. And for single-zone growing chambers, at least 8.5-9 m/sec.
  3. If ventilation is without air ducts, with forced exhaust only, it is important to increase the speed in the passages. That is, the air should passively enter not over the entire surface of the wall, but through the openings opposite the passages. The smaller the hole, the higher the speed. The hole in the wall should be narrow, but high, so that the flow passes near all tiers of blocks in height.

If the humidity of the substrate is high (the figure can be from 69 to 74% - it depends on the method of preparing the raw materials and on the properties of the raw materials themselves) - the air humidity in the chamber should be kept 3-4% below optimal.

Since oyster mushrooms absorb an increased amount of moisture from the substrate and must be able to evaporate it. Here it is important to choose the correct % humidity depending on the room temperature.

You need to make sure that the mushroom does not dry out and at the same time is not too wet.

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