Detailed Guide to Straw Mushroom Cultivation: Planting Methods and Management Essentials

Straw mushroom cultivation originated in southern China and has a cultivation history of more than 200 years. The straw mushroom not only has plump, tender, crisp and smooth flesh and a delicious taste, but also has very high nutritional value, containing rich protein, essential amino acids for the human body, and vitamin C. Eating straw mushrooms regularly can enhance the human body's immunity to diseases, and also has certain effects in fighting cancer and treating disease, lowering plasma cholesterol, and lowering blood pressure; it is also a good food for diabetic patients, a food that is both tasty and health-promoting, and is extremely popular in domestic and international markets. Cultivating straw mushrooms has significant economic benefits, with a general input-to-output ratio of 1:2-3, making it an industry with great development prospects.

I. Morphological Characteristics of the Straw Mushroom

The morphology of the straw mushroom can be divided into two main parts: the mycelium and the fruiting body. To the naked eye, the mycelium appears pale white, semi-transparent, thread-like, and branched. When the fruiting body first forms, it is a small smooth white dot; after 1 to 2 days a primordium forms; after 3 to 4 days the stipe elongates, the cap breaks through the volva, and it becomes a mature, opened fruiting body. The fruiting body consists of four parts: the cap, the gills, the stipe, and the volva.

II. Living Conditions of the Straw Mushroom

1. Nutrition: The nutrients required by the straw mushroom are mainly carbohydrates, nitrogen, and various minerals, and a certain amount of vitamins is also needed. These include sugars, starch, hemicellulose and cellulose; organic nitrogen and inorganic nitrogen; and mineral elements such as potassium, phosphorus, calcium, sulfur, manganese, and magnesium. Generally speaking, the nutrients required by the straw mushroom can be obtained from cottonseed hulls, waste cotton, rice straw, cow dung, wheat bran, rice bran, sugarcane bagasse, and soil.

2. Temperature: The straw mushroom is a high-temperature type fungus. The temperature range for mycelial growth is 20-40°C, with the optimum being 32-35°C. Below 20°C growth is extremely weak, at 10°C growth stops, and below 5°C or above 45°C the mycelium quickly dies. The temperature range for fruiting body formation is 25-35°C, with the optimum being 28-33°C; below 20°C or above 35°C is unfavorable for the growth and development of the fruiting body.

The straw mushroom is a constant-temperature fruiting type fungus, and during the period of fruiting body formation and development it is very sensitive to changes in external temperature. A climate of sudden cold and sudden heat is extremely unfavorable for fruiting body growth. The cultivation season requires the air temperature to be stable above 20°C, otherwise the yield will not be high or stable.

3. Moisture: Insufficient moisture causes drought and low yields. Too much moisture leads to poor aeration, inhibits respiration, and causes large numbers of mycelia and primordia to die. Practice has proven that a moisture content of 60%-65% in the substrate is suitable for the growth of straw mushroom mycelium, and it must not exceed 70%. During fruiting body development, the relative air humidity is required to reach 85%-90%. Above 95%, the straw mushroom rots easily and is prone to infection by contaminant fungi; below 80%, the straw mushroom grows slowly, its surface is rough, it lacks luster, and the yield is low.

4. Air: Sufficient oxygen is an important condition for the normal growth and development of the straw mushroom. With insufficient oxygen and excessive accumulation of carbon dioxide, growth often stops or the fungus dies because respiration is inhibited. Therefore, when cultivating, choose a site with slow air convection. If ventilation is too strong, moisture is easily lost, which is also unfavorable for the growth of the straw mushroom.

5. Acidity and alkalinity (pH): The straw mushroom prefers a slightly alkaline environment. For basidiospore germination of the straw mushroom, a pH of 6-7.5 is suitable. The mycelium has broad adaptability to pH and can grow at pH 4-10.3, while the suitable pH for fruiting body growth is 8. When formulating the substrate, a pH of 7.5-8 is suitable.

6. Light: Mycelial growth does not require light; direct sunlight instead inhibits mycelial growth. The formation and development of the fruiting body requires a certain amount of scattered light. With relatively strong light, the fruiting body is dark black and glossy, robust, strong in disease resistance, and dense in tissue; with insufficient light, the fruiting body is gray and dull, or even white, and the mushroom tissue is also relatively loose. However, strong direct light has a severely inhibiting effect on the fruiting body. Therefore, straw mushrooms cultivated outdoors must be covered with straw screens.

III. Cultivation Techniques for the Straw Mushroom

1. Determining the Cultivation Season

According to the temperature requirements for the growth and development of the straw mushroom and the local climate characteristics, for indoor shelf cultivation, the sowing period is from late June to early September; for outdoor cultivation in plastic medium tunnels or large tunnels, the sowing period should be chosen from early July to late August. Generally, after the "plum rain season" ends, material piling begins. The straw mushroom has a short growth period; from sowing to the end of harvesting is generally about one month, so 2-3 crops can be cultivated continuously in the same cultivation site.

2. Substrate Formula and Piling

Cottonseed hulls, waste cotton, and rice straw can all be used to cultivate straw mushrooms, but they must be fresh and free of mold. Before piling the material, sun-dry it for 2-3 days to kill contaminant fungi and pests. When mixing the material, add 5% lime powder, mixing the lime powder into limewater to mix the material. Pile the moistened cotton hulls or waste cotton into a pile 1 m high and 1.5 m wide, with unlimited length, pat it slightly firm, punch several holes with bamboo poles to facilitate aeration and promote microbial activity, then cover with plastic film. Turn the pile once on the third day, for a total piling time of 5-6 days. Before sowing, add 0.1% carbendazim. Mix the carbendazim into a liquid medicine and spray it with a sprayer, spraying while turning the material, striving for evenness. The pH value of the well-piled material must be measured; if the pH value does not reach 8, adjust it with limewater so that the pH value of the substrate reaches 8-9.

3. Building the Shed and Making the Beds

Choose high ground with convenient drainage and close to a water source to build the shed. The shed roof is 1.3 m high, 2 m wide, and about 8 m long. Inside the shed, leave an aisle 0.4 m wide and 0.3 m deep in the middle, and leave 0.8 m on each side as mushroom beds. Build the frame with bamboo strips and cover it with agricultural film and straw screens. Dig drainage ditches around the outside of the shed. Before sowing, disinfect the mushroom beds by splashing them with 5% limewater.

4. Sowing and Management

Spread the well-piled substrate on the bed surface, using 25-30 jin per sq m, depending on the temperature. If the air temperature is high, the substrate should be slightly thinner; if the air temperature is low, the substrate can be thicker. Spread the material in ridges or in a wave shape. Use broadcast sowing for the spawn, with a spawn rate of 10%; it can also be calculated per sq m, using 2 bags of spawn per sq m. After sowing, press it slightly firm and cover with film to retain heat and moisture. Management during the mycelial growth period is mainly about coordinating the contradiction between aeration and heat and moisture retention. The straw mushroom is an aerobic fungus with a relatively large oxygen demand, so the number of days with film covering is generally kept at 2-3 days. If the material temperature exceeds 36°C, uncover the film for aeration; if the material temperature is below 36°C, aerate 2-3 times a day for 0.5 hour each time. To facilitate management, 4-5 days after sowing (when the mycelium has covered the bed surface), carry out casing soil, with a soil layer of about 1 cm, that is, just enough not to expose the cotton hulls, and the soil particles should be fine. After casing, spray and soak with clarified 1% limewater, and keep the soil particles moist at all times. Generally, on the eighth to tenth day after sowing, primordia form. After the straw mushrooms form, do not spray water directly onto the mushroom bodies; spray or sprinkle water into the air or onto the ground to keep the relative air humidity in the mushroom house above 85%.

5. Harvesting and Between-Flush Management

The straw mushroom grows quickly; generally, from primordium formation to harvest takes only 4-5 days. Harvest when the base of the mushroom body begins to elongate and the volval membrane has not yet broken. During the peak harvest period, harvesting must be done twice a day. The biological conversion rate of the first flush is generally 20%.

Because the mycelium of the straw mushroom grows quickly and ages quickly, generally 2-3 flushes are harvested, with a total biological conversion rate of 30-40%. After the first flush harvest is finished, promptly clean the bed surface and dig out dead mushrooms and mushroom stipes. Then spray 1% limewater to adjust the pH value of the substrate and increase the moisture content of the material, cover with film for 1-2 days, and generally the second flush appears after 5-7 days. Management after fruiting is the same as above.

6. Early and Delayed Cultivation of the Straw Mushroom

Choose a house or foam room or shed with good insulation as the cultivation site, which is conducive to raising and maintaining temperature. Use coal or coal briquettes as heating fuel. Use pipeline heating, and be careful to discharge combustion exhaust gas outdoors. Use shelf cultivation, replenish moisture, and strengthen insulation and ventilation management.

Other management techniques are the same as conventional straw mushroom cultivation.