Cultivation technology of Oyster Mushroom

This mushroom is simple to grow and has excellent flavour and texture. It is very popular in many countries particularly in South-East Asia, where cultivation of button mushroom (Agaricus bisporus) is not possible under natural climatic conditions. Besides its delicious taste, it is known to be very nutritious and is recommended to control obesity and is reported to be beneficial for diabeties. Its low fat content makes it an ideal diet for the blood pressure patients.

The Pleurotus mushroom is generally referred to as `Oyster Mushroom' or `Dhingri' in India. It is a basidiomycete and belongs to the Genus `Pleurotus'. The fruit bodies of this mushroom are distinctly shell, fan or spatula shaped with different shades of white, cream, grey, yellow, pink or light brown depending upon the species. The oyster mushroom is one of the most suitable fungal organism for producing protein rich food from various agrowastes without composting.

Substrate preparation:

The popular methods of substrate preparation are as follows.

·         Steam pasteurization

·         Hot water treatment

 Steam pasteurization:

In this method pre-wetted straw is packed in wooden trays or boxes and then kept in a pasteurization room at 60-80C for few hours. Temperature of the pasteurization room is manipulated with the help of steam through a boiler. Substrate after cooling at room temperature is seeded with spawn. The entire process take 3-5 days.

Hot water treatment:

The substrate after chopping (5-10 cm) is soaked in hot water (65 to 70°C) for one hour or 60 to 120 minutes at 80C or in case of paddy straw at 85C for 30-45 minutes. After draining excess water spawn is added. The leached water contains a lot of soluble sugars and phenolic compounds. Hot water treatment makes the hard substrate like maize cobs, stems etc. soft so the growth of mycelial takes place very easily. This method is not suitable on large scale commercial cultivation.

Spawning:

Freshly prepared (20-30 days old) grain spawn is best for spawning. Old spawn (3-6 months) stored at room temperature (20-30C) forms very thick mat like structures due to mycelium aggregation and sometimes young pinheads and fruitbodies start developing in the spawn bottle itself. The spawning should be done in a pre-fumigated room (48 h with 2% formaldehyde). The spawn should be mixed @ 2 to 3% of the wet wt. of the substrate. One bottle of spawn of 300 g is sufficient for 10-12 kg of wet substrate or 2.8 to 3 kg of dry substrate wt. Spawn can be mixed thoroughly or mixed in layers. Spawned substrates can be filled in polythene bags (60 x 45 cm) of 125-150 gauze thickness. Ten to 15 small holes (0.5-1.0 cm dia) should be made on all sides especially two to four holes in the bottom to leach out excess water. Perforated bags give higher and early crop (4-6 days) than non-perforated bags because of accumulation of high CO2 which inhibits fruiting. One can use empty fruit packing cartons or wooden boxes for filling substrate. Polythene sheets of 200-300 gauze thickness of 1.25 x 1.25 m are spread in rectangular wooden or metal box. Spawned substrate is filled and the polythene sheet is folded from all the four sides to make a compact rectangular box. It is tightly pressed and tied with a nylon rope. The block is incubated as such and after mycelium growth polythene sheet is removed.

Cropping:

The spawned bags or blocks are kept in incubation room for mycelial growth. Spawn bags can be kept on a raised platform or shelves or can be hanged in cropping room for mycelial colonization of the substrate. During mycelial growth the bags are not to be opened or no ventilation is needed. Moreover, there is no need for any high relative humidity, so no water should be sprayed.

Once the mycelium has fully colonized the substrate and forms thick mycelial mat it is ready for fruiting. Contaminated bags with mould may be discarded while bags with patchy mycelial growth may be left for few more days to complete the mycelial growth. There is no need for casing the substrate. All the bundles, cubes or blocks are arranged on wooden platforms or shelves with a minimum distance of 15-20 cm between each bag in the tier.

Harvesting:

Pick the mushrooms while the edges of the caps are still curled down. If you leave the mushrooms to grow bigger, you will end up with poorer quality mushrooms and it also means fewer mushrooms later on. 

Pick all the mushrooms at the same time by twisting them off at the base. Be careful not to pull out the substrate. 

Don't cut the mushrooms off at the base, this is going to make the stump rot - a rotten stump means fewer mushrooms on your next flush. 

Once you have picked your first flush, keep on watering your Mushroom Factory. Your factory should produce between 2 and 4 flushes of mushrooms. Your most successful crops are usually the 1st and 2nd because this is when there are the most nutrients for the mushrooms to feed off.

From the time your mushrooms start growing, they should double in size every day. They will be ready to pick after about a week.

Medicinal and nutritional value of oyster mushroom:

There are 42 calories in one cup of oyster mushrooms, making them a low-calorie addition to any meal. Oyster mushrooms are also high in nutrients. According to a study published in "Food Chemistry," oyster mushrooms contain significant levels of zinc, iron, potassium, calcium, phosphorus, vitamin C, folic acid, niacin, and vitamins B-1 and B-2. The study concluded that consuming oyster mushrooms as part of a healthy diet contributes to recommended nutritional requirements.