How to Grow Straw Mushrooms? A Detailed Tutorial on the Latest Techniques and Methods

The straw mushroom has tender flesh, a crisp and smooth texture, a delicious flavor, and rich nutrition, with excellent health benefits; it is a high-quality edible mushroom. Whether as fresh mushrooms, dried products, or canned straw mushrooms, its products 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 shopping baskets, but also sells at a relatively high price, with good economic returns. The straw mushroom is one of the fastest-harvested edible mushrooms; from sowing to harvest takes only about 2 weeks, and a single cultivation cycle takes only 20-30 days. Moreover, no special equipment is needed, and it can be cultivated both indoors and outdoors. Developing straw mushroom cultivation can make use of agricultural by-products such as cottonseed hulls, rice straw, sugarcane bagasse, and corn stalks as cultivation materials.

Growing Conditions for Straw Mushrooms

1. Nutrition: The nutrients required for the growth and development of straw mushrooms are mainly carbohydrates, nitrogenous nutrients, 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 matter 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 easily rots 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 such as dried cow dung, chicken manure, wheat bran, rice bran, and cornmeal is added to the above materials to supplement nitrogenous nutrients 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, with the optimum temperature being 28-32°C. Growth stops at 10°C, and above 45°C or below 5°C, the straw mushroom mycelium will die. Straw mushroom cultures cannot be stored in a refrigerator, to avoid freezing to death. The temperature range for fruiting body growth of straw mushrooms is 22-40°C, with the optimum temperature being 28-32°C. When the average temperature is below 23°C, fruiting bodies are difficult to form. When the compost temperature is below 28°C, fruiting body formation is affected, and below 25°C fruiting bodies are difficult to form. When the air temperature is below 21°C or above 40°C, as well as sudden weather 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, straw mushrooms easily die.

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 straw mushrooms proceed normally. With insufficient moisture, mycelial growth is slow and fruiting bodies are difficult to form; with excessive moisture, poor aeration is caused, mushrooms easily die, and contaminant organisms also easily occur. The optimum moisture 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. Contaminant organisms also easily occur. Therefore, during the management of straw mushroom cultivation, attention should be paid to ventilation to keep the air fresh. But attention must also be paid to moisture retention, and the relationship between ventilation, moisture retention, and temperature retention must be correctly handled.

5. Acidity and alkalinity (pH value): The straw mushroom is a fungus that prefers 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 easily infected by contaminant organisms. During cultivation, lime is generally added to adjust the pH value, usually at about 5% of the dry material weight, so that the pH value reaches 10-12. As the mycelium grows, the pH value gradually decreases; by the time fruiting bodies form, the pH value is around 7.5, which is just right for the growth and development of straw mushroom fruiting bodies.

6. Light: Neither the germination of straw mushroom basidiospores nor mycelial growth requires 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 their growth and development and the local air temperature conditions. Usually, cultivation can only begin when the daily average temperature reaches above 23°C. In the south, the period for cultivation using natural temperatures is from late May to mid-September on the Gregorian calendar. Cultivation from early June to early July is most favorable, because the temperature is suitable at this time and it is also the moldy-rain season, with high humidity, making temperature and humidity easy to control, with high yields and good mushroom quality. In midsummer (mid-July to late August), the temperature is relatively high, it is dry, and the amount of water evaporation is large. Management is relatively difficult, and it is harder to obtain high yield and high quality of straw mushrooms. In provinces such as Guangdong and Hainan, under natural 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 and plastic sheds for cultivation, it can be advanced or delayed as appropriate. If foam mushroom houses with heating equipment are used, year-round production is possible.

Varieties for Straw Mushroom Cultivation

By color, there are two major strains: one is called the 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, making it easy to pick. However, its stress resistance is relatively poor, and it is especially sensitive to temperature changes. The other is the 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, and the base of the mushroom body is relatively large, making picking relatively difficult, but it fruits quickly, has high yield, and has relatively strong stress resistance. According to the individual size of straw mushrooms, they can be divided into large, medium, and small types. Due to different uses, the requirements for straw mushroom varieties also differ. 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 locality 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. The yield is highest with waste cotton residue. Several commonly used compost preparations are introduced below:

1. Preparation of waste cotton residue compost

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

① Waste cotton residue + 5% lime

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, adding 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 1.2 m wide and about 70 cm high, with unlimited length, ferment for three days, and turn the pile once in between. The other is to make a wooden frame, 3.0 m long, 1.8 m wide, and 0.5 m high, placed on a cement 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, and so on layer by layer, pressing and treading until the frame is full; then lift the wooden frame upward and continue adding material and pressing and treading until the pile is about 1.5 m high. Ferment for 3 days.

2. Preparation of cottonseed hull compost

Cottonseed hulls, also called cottonseed skins, are also a relatively nutrient-rich material for straw mushroom cultivation, 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 cement floor, lime powder or supplementary materials added, fully mixed while wet, then piled up, covered with plastic film, and fermented for three days, with one turning of the pile in between. When turning the pile, if the inside of the pile is too dry, lime water should be added to adjust it. When it is put on the bed, the moisture 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 materials for straw mushroom cultivation. Because the physical properties of rice straw and wheat straw are relatively poor and their nutrients are lacking, as long as they are properly treated and supplementary materials are added, relatively good yields can also be obtained. Each square meter requires 10-15 kg of dry rice straw.

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

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

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

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

There are two ways to treat the above rice straw or wheat straw: one is not to cut the rice straw or wheat straw, 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, 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 "8"-shaped straw bundles 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, and turn 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 being piled with lime and supplementary materials.