Detailed Explanation of Key Techniques for Off-Season Shiitake Mushroom Cultivation

1. Preparatory work. The raw materials are corn cobs, sawdust and cottonseed hulls; the auxiliary materials are fine rice bran or wheat bran. Before using the greenhouse, use 15 grams of sulfur per cubic meter; when ignited it produces sulfur dioxide, which has strong sterilizing power and is used to disinfect the greenhouse. When fumigating the greenhouse with sulfur, the doors and windows must be tightly closed and people must leave to avoid poisoning. A 3% Lysol solution and Bordeaux mixture can also be used to disinfect the greenhouse. Before fruiting, the greenhouse interior must be dry, with relative air humidity kept at around 70%; dampness easily causes contamination by foreign fungi. To make full use of the space, racks can be set up inside the greenhouse, with each layer 30 cm high, up to 5 layers, leaving walkways between the racks. Alternatively, no racks are needed, and the mushroom blocks can be stacked directly on the ground up to 1 m high.

2. Preparing the growing substrate. Formula: corn cobs or broadleaf wood sawdust; in cotton-producing areas, cottonseed hulls can also be used at 80%, fine rice bran or wheat bran at 18% (use only 1 kind), and sugar and gypsum at 1% each. To prevent mold infection, add 1 kg of carbendazim per 1000 kg of substrate. Crush the corn cobs to the size of beans. Weigh and mix the materials in proportion, add clean water so that the water content reaches 60%, that is, when the substrate is squeezed in the hand, water appears between the fingers but does not drip down; pH 5.5-6.0.

3. Filling the bags. The inoculation room should first be fumigated with sulfur or sprayed with Lysol for disinfection. Inoculation personnel should wear clean clothes, wash their hands thoroughly, and then wipe their hands with 75% alcohol cotton. All utensils must be sterilized by boiling or soaked in 0.5% potassium permanganate solution for disinfection. Prepare plastic bags 17-30 cm in diameter and 50 cm long. Mix the growing substrate in proportion, add water and stir evenly, and fill the bags immediately. Fill each bag with about 5 kg of substrate, move them into the inoculation room, or inoculate immediately while filling the bags.

4. Inoculation. During inoculation, pay attention to aseptic operation: wear a mask, wear a white hat, cover the hair, wash hands with soap, and then wipe hands with 75% alcohol cotton. There are two inoculation methods. One is layered inoculation, carried out at the same time as filling the bags. First tie off one end of the bag, pour in 1-2 bottles of spawn, then add substrate; when the bag is half filled, pour in 2 more bottles of spawn; when the bag is full, pour in another 1-2 bottles of spawn, then tie off the opening. Each bag uses 0.5-1 kg of spawn. The other inoculation method is hole inoculation, punching 6 holes in each bag. Make a small wooden stick 1.5 cm thick with a flat top; aim it at the filled plastic bag and press hard to punch 1 hole; pick up spawn with the hand and insert it into the hole, inoculating 100-200 grams per hole. The inoculated holes do not need to be sealed with adhesive tape and can be left exposed, which is beneficial for ventilation and oxygen supply.

5. Management during the mycelial growth stage. Stack the inoculated spawn bags together up to 1 m high, leaving walkways. Cover the bag stacks with a layer of kraft paper to block light and keep warm. In greenhouses with racks, the spawn bags can be placed individually on the racks, also covered with kraft paper. In the morning, promptly open the straw mats and paper quilts on the greenhouse roof, and cover them again at night. During the mycelial growth stage, keep the greenhouse temperature at 5-15°C and cultivate the mycelium at low temperature; it should not exceed 20°C, otherwise large amounts of foreign fungi will develop. Do not sprinkle or spray water inside the greenhouse; keep it dry, with relative air humidity kept at around 70%. When the mycelium on both sides of the spawn bag has reached 5 cm, loosen the ties at both ends of the bag a little to let air in and increase ventilation and oxygen supply. After 40-45 days, the mycelium fills the bag and begins to change color, from white to yellowish brown, and the entire mushroom block becomes a single entity. At this point, the openings at both ends of the bag can be fully opened to increase ventilation; the color-changing period is 10-15 days.

6. Management during the fruiting stage. After the entire mushroom block has turned yellowish brown and exudes some yellowish-brown water, switch to fruiting-stage management. At this time, increase the humidity in the greenhouse; water can be sprinkled on the ground, and a sprayer can be used to spray water in the air, so that the relative air humidity reaches above 90%. Appropriately increase light transmission, but still do not let sunlight fall on the mushroom blocks. Keep the daytime temperature at 15-20°C and the nighttime temperature at 5-10°C, creating a certain temperature difference. For those placed individually, the spawn bags can be removed; those that cannot be placed individually can still be stacked together without removing the bags, only rolling up the openings at both ends, and carrying out simple grading, cutting off 1 segment of the mushroom stem, and promptly transporting them to market for sale. They must not be stored for long, to avoid losses from rotten mushrooms. If they cannot be sold immediately, they can be promptly dried by machine, sun-dried, or salted.