Structural Divisions of an Oyster Mushroom Production Farm

Larisa Teslenkova, consultant-technologist, author of the website and YouTube channel “Oyster mushroom expert”.
https://veshenka-expert.info/
https://youtube.com/@oystermushroom_expert-tech?si=WPFm7LUETjL0bDXn
https://veshenka-expert.info/en/oyster-mushroom-cultivation-technology/

In the previous article, I mentioned that before starting any work on equipping the premises, it is important to assess their suitability for growing oyster mushrooms and the costs of repairs, especially if you are renting these buildings.

In this series of articles, I will discuss the necessary production areas and how to determine if your structures are suitable for growing oyster mushrooms.

There will be three articles in total. In this one, I will provide an overview of the structural divisions of a mushroom farm. In the second article, I will describe the disadvantages and advantages of working with purchased substrate. In the third article, I will focus on describing the substrate section and substrate processing technologies in detail.

Structural Divisions of an Oyster Mushroom Production Farm

Spawn Production Laboratory

In farms producing less than 15 tons of mushrooms per month, ready-made spawn is usually purchased. However, some medium and, more often, large farms still prefer to produce their own mother spawn (first-generation spawn) from purchased liquid cultures. They then produce the second generation of spawnfor use on their own farm and for sale to other mushroom farms.

Economically, this is justified in most cases, but capital and monthly expenses should still be calculated mathematically.

It is important to note that on the farm, the spawn laboratory, substrate workshop, and mushroom cultivation are separate production units. This means they should have their own staff, a spawnproduction technologist, and a manager.

Any room can be adapted for a laboratory – high ceilings or special requirements are not needed. However, microbiological cleanliness is very important. Therefore, buildings where animals or birds were once kept are not suitable.

Required rooms:

• Grain storage warehouse
• Room for filling grain into bags
• Autoclaving room
• Clean zone where the autoclave unloading lid is located and inoculation of the mother grain with mushroom culture takes place
• Incubators for grain colonization with mycelium, accessible from the clean zone
• Changing room and bathroom for staff
• Refrigerated chambers for spawn storage

IMPORTANT: Spawn (produced on-site or purchased) must be stored in a separate refrigerated chamber!

In the clean zone of the laboratory, ventilation with high-quality phased air purification by industrial filters (coarse, fine, and high-efficiency filtration) is required – to remove large particles, dust, plant seeds, mold spores and bacteria, pollen.

The laboratory area depends on the volumes of spawn production and is calculated by a specialist. Spawn production is not my specialty, so I do not provide specific figures.

Substrate Workshop

I will discuss the areas of the substrate workshop in the third article of this series, as it depends not only on the amount of substrate produced but also on the farm’s work schedule and the raw material processing method (sterilization or pasteurization).

Oyster Mushroom Growing Rooms

This section is an essential attribute of any mushroom farm. Small farms use a two-zone growing system – where mycelium colonization takes place in one room, called an “incubator,” and mushroom growth occurs in another room – the growing room. In many countries, the term “growing room” is more familiar. In the two-zone system, the climate in the rooms does not change. In the incubator, a microclimate is created only for block colonization. In the growing room, the climate is set for mushroom growth, without considering the features of different growth stages. I believe that for production volumes of more than 6 tons of oyster mushrooms per month, the two-zone growing system is impractical. It is necessary to use a multi-room (single-zone) growing system – where the substrate is loaded into the room and the climate changes depending on the stage of mycelium development, and then – the fruiting body growth stage. In a separate article dedicated to climate, I will describe in more detail the advantages of the single-zone system for large farms.

The growing rooms should be at least 3.0-3.3 meters high, with concrete floors, insulated walls, and ceilings. Their area depends on the placement of the blocks, their weight, and partly on the chosen air circulation system. Also, consider how the harvested mushrooms will be delivered for trimming and packaging. In many cases, farms use a building structure adopted from mushroom complexes – a corridor from which you can access the growing rooms, where the ventilation system is located, empty boxes are stored, and carts or forklifts with harvested mushrooms are moved.

Processing and Cooling Area

At some farms, the clusters are plucked and immediately trimmed during the harvest. However, in most cases, this is done in a separate room. If you plan to package mushrooms, remember to allocate space for workers and packaging equipment. From the processing room, there should be a passage (or drive if boxes of mushrooms are transported on a cart or electric cart) to refrigerated chambers with industrial monoblocks maintaining the temperature inside the refrigerator from +3 to +5 degrees Celsius. The refrigerated chambers should have insulated doors, walls, floors, and ceilings. They can be constructed inside the building from sandwich panels.

Auxiliary and Utility Rooms

Plan where the changing rooms and utility rooms for workers, storage for chemical reagents, necessary inventory, and consumables will be located.

Additionally, it is important to note that the production site should have its own transformer substation, well, and sewage system. Their capacities should be calculated by profile specialists based on the data provided by the project technologist.