Detailed Tutorial on the Latest Straw Mushroom Cultivation Techniques

The straw mushroom has tender flesh, a crisp and smooth texture, a delicious taste, and is rich in nutrients, with excellent health benefits; it is a high-quality edible mushroom. Its products, whether fresh mushrooms, dried products, or canned straw mushrooms, are deeply loved by consumers in domestic and international markets. Especially in the hot summer weather, when other edible mushrooms are scarce, it is precisely the peak season for straw mushrooms, and at the same time it is the off-season for vegetables. Therefore, it can not only enrich people's food basket, but also sells at a relatively high price, with good economic returns. The straw mushroom is one of the fastest-harvested edible mushrooms; from spawning to harvest takes only about 2 weeks, and one cultivation cycle takes only 20-30 days. Moreover, it requires no special equipment and can be cultivated both indoors and outdoors. Developing straw mushroom cultivation can make use of agricultural and sideline products - such as cottonseed hulls, rice straw, sugarcane bagasse, corn stalks, and other cultivation materials.

Growth Conditions of the Straw Mushroom

1. Nutrition: The nutrients required for the growth and development of the straw mushroom are mainly carbohydrates, nitrogen nutrition, and minerals; in addition, a certain amount of vitamins is also needed. These substances can generally be obtained from materials such as rice straw or cottonseed hulls. The straw mushroom is a saprophytic fungus; it must absorb nutrients from dead plant bodies and soil. For cultivating straw mushrooms, materials such as rice straw and cottonseed hulls that are not moldy or deteriorated should be selected; wet straw that has not been sun-dried is prone to rot and is not suitable for use. In addition, waste cotton, sugarcane bagasse, green thatch grass, and peanut vines can all be used as materials for cultivating straw mushrooms. If an appropriate amount of supplementary materials is added to the above materials, such as dried cow dung, chicken manure, wheat bran, rice bran, cornmeal, etc., to supplement nitrogen nutrition and vitamins, the yield of straw mushrooms can also be increased.

2. Temperature: The straw mushroom is a high-temperature fungus. The temperature range for mycelial growth is 10-42°C, and the optimum temperature is 28-32°C. At 10°C growth stops; above 45°C or below 5°C, the straw mushroom mycelium will die. Straw mushroom spawn should not be stored in a refrigerator, to avoid freezing to death. The temperature range for fruiting body growth of the straw mushroom is 22-40°C, and the optimum temperature is 28-32°C. When the average temperature is below 23°C, it is difficult for fruiting bodies to form. When the compost temperature is below 28°C, fruiting body formation is affected; when it is below 25°C, it is difficult for fruiting bodies to form. When the air temperature is below 21°C or above 40°C, as well as sudden climate changes, there is a fatal effect on small mushroom buds. Fruiting bodies are extremely sensitive to sudden temperature changes; if the compost temperature changes by more than 5°C within 12 hours, the straw mushroom is prone to dying.

3. Humidity: The straw mushroom is a fungus that likes a high-temperature and high-humidity environment. Only under suitable moisture conditions can the growth and development of the straw mushroom proceed normally. If moisture is insufficient, mycelial growth is slow and it is difficult for fruiting bodies to form; if moisture is excessive, it causes poor ventilation, easily leading to mushroom death, and contaminating microorganisms are also likely to occur. The optimum water content of the compost is about 70%, the optimum air humidity during the mycelial growth stage is about 80%, and the relative air humidity during the fruiting body growth stage is required to be above 90%.

4. Oxygen: The straw mushroom is an aerobic fungus, and sufficient oxygen is an important condition for its growth. If oxygen is insufficient and carbon dioxide accumulates too much, fruiting bodies will be inhibited or even die. Contaminating microorganisms are also likely to occur. Therefore, in the management process of cultivating straw mushrooms, attention should be paid to ventilation and air exchange to keep the air fresh. But attention must also be paid to moisture retention, and the relationship between ventilation, moisture retention, and heat preservation must be correctly handled.

5. Acidity and alkalinity (pH value): The straw mushroom is a fungus that likes alkaline conditions. The optimum pH for straw mushroom mycelial growth is 7.8-8.5, and the optimum pH for fruiting body growth is 7.5-8. An acidic environment is unfavorable for the growth and development of the mycelium and makes it prone to infection by contaminating microorganisms. During cultivation, lime is generally added to adjust the pH value, with the amount added generally about 5% of the dry material weight, so that the pH value reaches 10-12. As the mycelium grows, the pH value will gradually decrease; by the time fruiting bodies form, the pH value is around 7.5, which is just suitable for the growth and development of straw mushroom fruiting bodies.

6. Light: The germination of basidiospores and the growth of mycelium of the straw mushroom do not require light; direct sunlight instead hinders mycelial growth. Light, however, promotes the formation of fruiting bodies. The formation of fruiting bodies requires a certain amount of scattered light, and the most suitable light intensity is 300-350 lux. The intensity of light not only affects the yield of straw mushrooms but also directly affects the quality and color of the fruiting bodies. When light is strong, the fruiting bodies are dark in color and glossy, and the fruiting body tissue is dense; when light is insufficient, the fruiting bodies are dull or even grayish-white, and the fruiting body tissue is also looser. Without light, the fruiting bodies are white. Strong direct sunlight has a serious inhibitory effect on fruiting bodies, and open-field cultivation must have shading conditions.

Cultivation Season for Straw Mushrooms

The cultivation season for straw mushrooms under natural conditions should be determined according to the temperature required for the growth and development of straw mushrooms and the local air temperature conditions. Usually, cultivation can only be carried out when the daily average temperature reaches above 23°C. In the south, the time for cultivation using natural air temperature is from late May to mid-September on the Gregorian calendar. Cultivation from early June to early July is most favorable, because at this time the temperature is suitable and it is also the moldy rain season, with high humidity; temperature and humidity are easy to control, the yield is high, and the mushroom quality is good. In the midsummer season (mid-July to late August), the temperature is relatively high and dry, and the amount of water evaporation is large. Management is relatively difficult, and it is more difficult to obtain high yield and high quality of straw mushrooms. In provinces such as Guangdong and Hainan, under natural air temperature conditions, cultivation of straw mushrooms is more suitable from April to October. In northern regions, cultivation from June to July is appropriate. When using greenhouses or plastic sheds for cultivation, it can be advanced or delayed as appropriate. If a foam mushroom house with heating equipment is used, year-round production is possible.

Varieties for Straw Mushroom Cultivation

According to color, there are two major strain groups: one is called black straw mushroom, whose main feature is that the wrapper of the unopened fruiting body is mouse-gray or black, oval in shape, not easy to open, with a relatively small base, and easy to pick. However, its stress resistance is relatively poor, and it is especially sensitive to temperature changes. The other is called white straw mushroom, whose main feature is that the wrapper of the fruiting body is grayish-white or white, the wrapper is thin, it opens easily, the base of the mushroom body is relatively large, and picking is relatively difficult, but it fruits quickly, has high yield, and has relatively strong stress resistance. According to the individual size of the straw mushroom, it can be divided into large, medium, and small types. Due to different uses, the requirements for straw mushroom varieties are also different. For making dried straw mushrooms, large types with thick wrappers are preferred; for canning, medium and small types with thick wrappers are needed; for fresh-sale straw mushrooms, there are no strict requirements for wrapper and individual size. Each place can choose suitable varieties for cultivation according to its needs.

Preparation of Straw Mushroom Compost

The raw materials for cultivating straw mushrooms are broad, mainly using raw materials rich in cellulose and hemicellulose. Such as waste cotton residue, cottonseed hulls, rice straw, and wheat straw. Waste cotton residue gives the highest yield. Several commonly used compost preparations are introduced below:

1. Preparation of waste cotton residue compost

Waste cotton residue is also called waste cotton, cracked-seed cotton, floor cotton, or foot cotton, and comes from cotton processing plants. Waste cotton residue has a long heating time and good heat and moisture retention performance, and is currently the most ideal straw mushroom cultivation material. About 12 kg of waste cotton residue is needed per square meter. Commonly used formulas include:

Formula ①: waste cotton residue + 5% lime

Formula ②: waste cotton residue + 10% bran (or rice bran) + 5% lime powder

There are two methods for preparing the compost: one is to build a pool, soak the waste cotton residue in lime water, add 5 kg of lime powder per 100 kg of waste cotton residue, soak for 5-6 hours, then scoop it out and make a pile, with a pile width of 1.2 m, a pile height of about 70 cm, and unlimited length; ferment for three days, turning the pile once in between. The other is to make a wooden frame, that is, 3.0 m long, 1.8 m wide, and 0.5 m high, placed on a concrete floor. Then spread a layer of waste cotton residue in the wooden frame, about 10-15 cm thick, sprinkle a thin layer of lime powder, sprinkle water and press and tread so that the waste cotton residue absorbs enough water, then sprinkle a layer of bran or rice bran, then spread another layer of waste cotton residue; press and tread layer by layer like this until the frame is full, then lift the wooden frame upward and continue adding material and pressing and treading until the pile height is about 1.5 m. Ferment for 3 days.

2. Preparation of cottonseed hull compost

Cottonseed hulls, also called cottonseed skin, are also a relatively nutrient-rich straw mushroom cultivation material, but their heat retention, moisture retention, and heat generation are not as good as waste cotton residue. The compost formula is the same as for waste cotton residue. In addition to the above two treatment methods, the cottonseed hulls can also be spread on a concrete floor, lime powder or supplementary materials added, fully mixed wet, then piled up, covered with plastic film, and fermented for three days, turning the pile once in between. When turning the pile, if the inside of the pile is too dry, lime water should be added to adjust it. When put on the bed, the water content of the material is about 70%, and the pH value is 8-9.

3. Preparation of rice straw or wheat straw compost

Rice straw and wheat straw are abundant raw materials and are traditional straw mushroom cultivation materials. Because the physical properties of rice straw and wheat straw are relatively poor and they lack nutrients, as long as they are properly treated and supplementary materials are added, relatively good yields can also be obtained. Dry rice straw of 10-15 kg is needed per square meter.

Formula ①: 87% rice straw or wheat straw + 5% plant ash + 1% compound fertilizer + 2% gypsum powder + 5% lime;

Formula ②: 88% rice straw or wheat straw + 5% bran or rice bran + 2% gypsum powder + 5% lime;

Formula ③: 73% rice straw or wheat straw + 5% dried cow dung + 15% fertile mud + 2% gypsum powder + 5% lime;

Formula ④: 83% rice straw or wheat straw + 5% bran + 5% dried cow dung + 2% gypsum powder + 5% lime

There are two treatment methods for the above rice straw or wheat straw: one is not chopping the rice straw or wheat straw and using long rice straw for cultivation. Soak the rice straw for about 12 hours, and place heavy objects on top of the rice straw so that it fully absorbs water. After soaking thoroughly, scoop it out and pile it for composting, with a pile width of 2 m and a pile height of 1.5 m, cover with plastic film to retain moisture, and pile-ferment for 3-5 days, turning the pile once in between. During cultivation, the long rice straw should be twisted into a figure-“8” shaped straw bundle and tied tightly, arranged closely bundle by bundle, stacked in two layers in a “pin” shape, with a thickness of 20 cm. The other is to cut the rice straw or wheat straw into 5-10 cm lengths or crush it with a grinder, soak it or directly mix it with lime water, and add supplementary materials, pile for 3-5 days, turning the pile once in between.

4. Preparation of mixed compost

In order to reduce production costs, a cultivation method using waste cotton residue or cottonseed hulls plus rice straw or wheat straw can be adopted, and relatively ideal results can also be obtained. The mixing ratio is usually 1/3-2/3 waste cotton residue or cottonseed hulls; the rice straw can be cut into sections or crushed, and used after piling with lime and supplementary materials.

Next, let me introduce the bed-frame cultivation technique for straw mushrooms!