Detailed Explanation of Key Techniques for Oyster Mushroom Cultivation in Greenhouses

Oyster mushrooms grow fast, have strong stress resistance, come from a wide range of substrate sources, are easy to cultivate and manage, and can be grown in all four seasons. In our province, greenhouse cultivation is the main method. Through extensive research, the author has compiled the cultivation techniques for greenhouse oyster mushrooms as a reference for fellow farmers.

1. Variety Selection

In early spring, medium-temperature varieties should be used; in late spring and early summer, medium- and high-temperature varieties should be used; in summer and autumn, high-temperature varieties should be used.

2. Production Season

For medium-temperature varieties, stock spawn is made in November-December, and production spawn is made in January-February; for high-temperature varieties, stock spawn is made in March-April, and production spawn is made in April-May.

3. Selection, Formulation and Treatment of Substrate

1. Selection of substrate: The substrate should be sourced locally. Cottonseed hulls, corn cobs, cotton stalk powder, bean stalk powder, sawdust (from broadleaf trees), rice straw, wheat straw, etc. can all be used, with cottonseed hulls being the best. Before use, all should be sun-dried for 1-2 days. Any that are moldy or deteriorated should not be used.

2. Substrate formulations: The following are commonly used in current production:

Rice straw substrate formulations: (1) Rice straw 50%, cottonseed hulls 30%, wheat bran 17%, sucrose 1%, superphosphate 1%, gypsum powder 1%; (2) Rice straw 76%, wheat bran 20%, sucrose 1%, superphosphate 2%, gypsum powder 1%; (3) Rice straw 74%, corn flour 25%, gypsum powder 1%, carbendazim 0.1%.

Cottonseed hull formulations: (1) Cottonseed hulls 98%, gypsum powder 2%, carbendazim 0.1-0.15%; (2) Cottonseed hulls 85%, wheat bran 12%, sucrose 1%, superphosphate 1%, gypsum powder 1%; (3) Cottonseed hulls 93%, superphosphate 2%, rapeseed cake 3%, gypsum powder 2%, lime water 0.5%.

3. Substrate treatment: Whether the substrate treatment method is correct or not determines the presence of contaminant organisms and the level of yield. Currently, substrate treatment for oyster mushroom production can be roughly divided into the following methods:

(1) Chemical treatment: In large-scale production, 0.2% carbendazim is mostly used to mix into the substrate, mainly utilizing the chemical to inhibit the germination and growth of contaminant spores. However, in high-temperature seasons, due to the high temperatures, the inhibitory effect of carbendazim is easily reduced, and contamination often still occurs, sometimes even severely.

(2) High-temperature treatment: Using high temperatures above 100°C for continuous steaming for 10-12 hours, then stopping the fire and leaving it sealed for 10-12 hours. However, this has the problems of long sterilization time, high energy consumption, and high cost. If sterilization is not thorough, it can also cause contamination.

(3) Pile fermentation treatment: Properly carrying out pile fermentation of the substrate is an effective measure to prevent contaminant contamination. If the substrate is further sterilized at high temperature for 2-3 hours after pile fermentation, the effect is even better.

4. Filling and Inoculation

1. Bed-style cultivation: Mostly used for raw material cultivation. Spread the already-treated substrate evenly on the mushroom bed to a thickness of about 12 cm. Use the layer-spawning method or the triangle hole-spawning method for inoculation, with a hole spacing of 10 cm. Finally, sprinkle a layer of spawn on the surface of the substrate to cover it, pat flat, then cover with plastic film and press down the edges.

2. Brick-style cultivation: Mushroom bricks are made using rectangular wooden molds with specifications of 90 x 50 x 12 (cm). When making them, first line the mold with plastic film, fill in the substrate, press flat, inoculate with spawn at a rate of 10-15% of the dry substrate weight, press firmly, then remove the wooden mold and wrap the brick tightly with plastic film.

3. Plastic bag-style cultivation: Plastic bags with openings at both ends are preferred. The size of plastic bags used for sterilized substrate depends on the type of substrate: for rice straw, the specification is 42 x 22.5 x 0.5 (cm); for cottonseed hulls, it is 49 x 15 x 0.5 (cm). For high-temperature sterilization, polypropylene plastic bags are used; for normal-temperature sterilization, polyethylene film is more economical.

5. Management

1. Mycelium running stage: Pay attention to changes in substrate temperature, which should be kept below 30°C. If the temperature exceeds 30°C, ventilation should be increased to cool down, and at the same time, shake the plastic film covering the mushroom bed or bricks, or turn over the mushroom bags to cool them down.

2. Fruiting stage: After oyster mushroom primordia appear, attention should be paid to ventilation and humidification management. For mushroom beds and bricks, remove the covering plastic film; for mushroom bags, open both ends; at the same time, increase humidity, maintaining relative humidity between 85%-90%.

6. Harvesting

Oyster mushrooms should be harvested promptly after maturing. The harvest standard is: the mushroom caps are fully expanded, the color has changed from dark to light, and spores have not yet been released; at this point, they can be harvested.