Production of Oyster Mushroom

Construction of the mushroom house is based on a simple basic design.

1. The dimensions depend on the number of substrate bags the grower can handle at any one time.
2. The walls are constructed out of farm bricks or poles and dagga or a wooden frame and thatch. Plastic or foam sheets may be used to line the walls to increase the relative humidity in the production house.
3. A roof thatched with grass or banana leaves.
4. Air vents and windows on the upper side of walls are required for ventilation and lighting to initiate fruiting. Light sufficient to read a  newspaper when in the house is adequate.
5. Wooden shelves for holding the bags or wooden racks for hanging spawned substrate bags.

The mushroom house should provide optimum conditions for fruiting. Temperatures should be maintained at 18 – 25°C and relative humidity should be  80–90%.
Incubation/Spawning room
• Spawned substrate bags are kept in this room for the mushroom mycelium to grow. Growers may construct a separate incubation room with shelves to hold the bags.
• Alternatively the spawned bags can be covered with black plastic in the mushroom house.
•If using the mushroom house for incubation the air vents and the windows should be closed to provide dark conditions required for spawning.
•Light is not required in the incubation room. Temperatures should be about 24°C

Mushroom Spawn
•Spawn referred to, as the mushroom seed is mushroom mycelium growing on sorghum, wheat or barley. It is used to seed substrate.
•High quality spawn should be obtained from reputable spawn laboratories.
• Good spawn is the key to successful mushroom production. Pleurotus ostreatus and Pleurotus sajor caju are the strains available locally for Oyster Mushroom production. Substrates or Substrate is the agricultural waste on which the mushroom grows.
Oyster mushroom can be  grown on several agricultural wastes;
•Finely chopped  rice or wheat straw
•Shredded maize cobs
•Cotton waste
•Finely chopped maize stalks
•Sawdust from broad-leaved trees like Banana leaves
The type to use depends on availability and accessibility.

Any of these substrates may be supplemented with rice or wheat bran at 15–20% and lime at 1–2%.
Any substrate used must be pasteurised to eliminate contaminants or undesirable organisms.

• A good substrate has the following properties;
•Easy availability
• High nutrient content for the mushrooms to grow
•Good aeration–not too compact and not too loose
•Good water holding capacity – not too dry and not too wet
•Wheat and rice straw are the most commonly used substrates in Oyster mushroom production.

Steriliser
The steriliser is required for pasteurising the substrate to eliminate pests and diseases.
The steriliser can be a huge pot, container or metal drum to hold large quantities of substrate for boiling in the water at 100°C.
Firewood or other local materials are used to provide the fire for heating the steriliser.
Other requirements Thermometer – used to check temperatures
Hygrometer – used for  monitoring relative humidity
Sprayer – for watering the  substrate during fruiting
• Watering can or bucket – for watering the floor in cooling the temperature and increasing the humidity
•Plastic bags – these are required for containing the substrate during the cultivation process.
•Bags should be 10 – 20kg capacity and preferably transparent. This makes it easy to check substrate colonisation and to detect contaminants.
•String – required for tying the mouths of bags and for hanging onto racks.

Production of Oyster
Mushroom production has four major steps.
1. Substrate preparation and  pasteurisation
2.Spawning
3.Incubation
4.Fruiting and Harvesting

Substrate Preparation and Pasteurisation

Pasteurisation aims at killing pests and diseases that can spoil the development of the mushroom.

Immersion in boiling water is a cheap but efficient way of pasteurising the substrate.
1. Prepare the substrate by chopping and shredding into small pieces.
2. Soak the substrate in water overnight.
3.Drain off the water and add the supplements
4. Pack the substrate into a  steriliser and fill with water – hot water is the best
5. Heat and pasteurise by boiling for 1hour.
6.Transfer the substrate onto a clean plastic sheet and cool to about 40°C just at the stage when you can hold it but not get burnt.
7. Pack the substrate into plastic bags taking care not to pack too tightly or too loosely.
8. Add the spawn whilst packing the substrate.

Spawning
This is the process of planting the mushroom.
1. Use about 0.5 kg or 300ml  of spawn to plant 10 kg of substrate.
2. Distribute the spawn evenly in alternating layers with the pasteurised substrate.
3. Tie the mouth of the bag  soon after spawning
•Substrate spawning is the most delicate operation in mushroom production.
• It must be done in a clean environment free of air movements
•Care should be taken not to contaminate the spawn itself and the substrate too.
•Workers must operate under strict hygienic conditions.

Incubation
•During incubation the mushroom mycelium grows to cover the whole substrate.
•Place spawned bags at 24°C in the dark incubation room or cover the bags with black plastic in the mushroom house.
•Bags are ready for mushroom formation when the substrate appears white.
•Full colonisation occurs in about 14–40 days.
•Transfer bags to the mushroom house or expose the bags by removing the black plastic.

Fruiting
Fruiting is the formation of the mushrooms in the mushroom house.
•Open the air vents or windows in the mushroom house to provide light and  to initiate fruiting
•After one day open the bags by making long cuts or holes at the top and at the bottom of the bags using clean sharp instruments.

Mushrooms will form through thee openings
•Mushrooms will begin to form in 3 to 4 days and will be ready for harvesting in the next 2 to 3 days.
•A temperature range of 20–  28°C and relative humidity of 80–95% is required in the mushroom house.
•Some measures have to be  taken during the process to ensure the development of good mushrooms:
1. To provide adequate moisture, water the substrate daily taking care not to overwater.
2.If temperatures rise to 30°C apply a light water mist to cool and to quicken fruiting.
3. The door and air vents or windows may be opened especially at night to allow cool air to enter.
4. Maintain high relative humidity by applying water on the floors and walls several times a day.

NB• Incomplete substrate colonisation delays fruiting.
Ensure that the substrate is well colonised.

Harvesting
Oyster mushrooms are harvested by gently twisting the stalk and pulling out.
•Harvest from the opened ends first.
•Make more long cuts or holes on the central portion of the bag so that more mushrooms develop
•Continue harvesting as long as the substrate appears white.
•The bags can be removed from the house when the substrate becomes colourless and soft to touch.
•A total weight of 10 to 20 kg of mushrooms can be harvested from 10 kg of dry substrate.
•The mushrooms will remain fresh for 3 to 6 days when kept in the refrigerator or in a cool area. They can also be dried using local methods of sun drying.

Problems in Mushroom Growing
The common problems are 1. Poor yields
2. Pests and diseases i.e. fungi, bacteria, insects and snail.

The best remedy as advised by #Afrostain #Farmtech is to prevent these problems by taking precautions in every stage of production.

1.Obtain high-quality spawn from reputable sources
2.Observe strict hygienic practices especially at  substrate preparation and spawning
3.Pasteurise the substrate  well
4. Sterilise all working instruments and equipment. Jik can be used for this  purpose.
5. Keep doors and window  closed or use a wire mesh for covering all openings to prevent insect from entering  the mushroom house
6. Keep the floors clean all the time
7. Do not touch any suspicious material during  harvesting
8. Throw used substrate a long distance away from the mushroom house.


Source

1.  Farm management handbook
2. #Afrostain #Farmtech
3. https://www.facebook.com/105416347635819/posts/140259104151543/?app=fbl