A detailed explanation of the latest scientific cultivation techniques for shiitake mushrooms, covering every stage

AbstractShiitake mushroom cultivation begins with the preparation of spawn. Once the cultivation season has been determined, the selection and proportional blending of the substrate can be carried out. After the substrate is fermented, it is bagged, then holes are punched and spawn is inoculated. Next come the mycelial growth management and color-turning management stages, followed by the operation to induce primordia. During the fruiting period, scientific management is required, and finally the shiitake mushrooms are harvested.

Shiitake mushroom is one of China's traditional specialty export products, and its top grade is the flower shiitake. The artificial cultivation of shiitake in China has a history of more than 800 years. For a long time, shiitake was cultivated using the “cut-flower method”, a log cultivation method relying on natural inoculation. It was not until the mid-1960s that pure spawn began to be cultivated, and the method was changed to log cultivation with artificial inoculation. In the mid-1970s, the compressed-block substitute cultivation method appeared, which later developed into the plastic-bag cultivation method, and yields increased significantly.

Mushrooms produced by log cultivation have high commercial quality, and the input-to-output ratio is also high, reaching 1:7 to 10, but a large amount of timber is needed, so it is only suitable for development in forest areas. Although substitute cultivation has a short production cycle and high biological efficiency, and can utilize various agricultural wastes, it can be widely developed in both urban and rural areas. However, substitute cultivation requires a large one-time input and has relatively high costs, with an input-to-output ratio of only 1:2. But through the application of beneficial bacteria in the culture, the input-to-output ratio can be raised to about 1:4, and high-temperature sterilization and the use of some anti-mold drugs are not needed.

Cultivation Process

Spawn preparation → determine cultivation season → substrate selection and proportional blending → substrate fermentation → bagging → hole punching and inoculation → mycelial growth management → color-turning management → primordia induction → fruiting management → harvest

Cultivation Conditions

1. Nutrition

Shiitake is a wood-rotting fungus, using cellulose, hemicellulose, lignin, pectin, starch, etc. as carbon sources for growth and development, but these must first be decomposed by corresponding enzymes into monosaccharides before they can be absorbed and utilized. Shiitake uses various organic and inorganic nitrogen sources as nitrogen sources; small-molecule amino acids, urea, ammonium, etc. can be absorbed directly, while macromolecular proteins and peptones must be degraded before absorption. The growth of shiitake mycelium also requires various mineral elements, among which phosphorus, potassium and magnesium are the most important. Shiitake also needs growth factors, including various vitamins, nucleic acids and hormones; most of these can be self-supplied, and only vitamin B 1 needs to be supplemented.

2. Temperature

The optimum temperature for shiitake mycelial growth is 23-25°C; below 10°C or above 30°C hinders its growth. The suitable temperature for fruiting body formation is 10-20°C, and a day-night temperature difference greater than 10°C is required. The shiitake varieties currently used in production include three temperature types: high-temperature type, medium-temperature type and low-temperature type. Their suitable fruiting temperatures are 15-25°C for the high-temperature type, 7-20°C for the medium-temperature type, and 5-15°C for the low-temperature type.

3. Moisture

The moisture required by shiitake includes two aspects: one is the water content within the culture medium, and the other is air humidity. The suitable amounts differ depending on whether substitute cultivation or log cultivation is used.

① Substitute cultivation. During the mycelial growth stage, the substrate water content is 55%-60%, and the relative air humidity is 60%-70%; during the fruiting stage, the substrate water content is 40%-68%, and the relative air humidity is 85%-90%.

② Log cultivation. During the mycelial growth stage, the substrate water content is 45%-50%, and the relative air humidity is 60%-70%; during the fruiting stage, the substrate water content is 50%-60%, and the relative air humidity is 80%-90%.

4. Air

Shiitake is an aerobic fungus. In the shiitake growing environment, due to poor ventilation, excessive accumulation of carbon dioxide and insufficient oxygen, mycelial growth and fruiting body development are both markedly inhibited, which accelerates the aging of the mycelium, makes the fruiting bodies prone to deformation, and also favors the breeding of contaminating microorganisms. Fresh air is a necessary condition for ensuring the normal growth and development of shiitake.

5. Light

The growth of shiitake mycelium does not need light; under completely dark conditions the mycelium grows well, while strong light can inhibit mycelial growth. During the fruiting body growth stage, scattered light is needed. If the light is too weak, there will be few mushrooms, the caps will be small, the stipes thin and long, and the quality poor, but direct light is also harmful to shiitake fruiting bodies.

6. pH

The growth and development of shiitake mycelium require a slightly acidic environment. The substrate can grow at a pH value of 3-7, with 5 being the most suitable; above 7.5, growth is extremely slow or stops. The optimum pH value for the occurrence and development of fruiting bodies is 3.5-4.5. In production, the pH value of the cultivation material is often adjusted to about 6.5. During pile fermentation, the pH value drops by about 0.5, and the organic acids produced during mycelial growth also lower the pH of the cultivation material.

Sowing Time and Spawn Selection

At present, shiitake production in northern China mostly uses greenhouses as fruiting sites, and is greatly affected by climatic conditions, with strong seasonality. The sowing period for shiitake in each place should be determined according to local climatic conditions.

In the Beijing area, shiitake production mostly uses summer sowing, with fruiting in autumn, winter and spring. Since the beginning of autumn fruiting is in mid-September, the specific sowing time should be in early July, and the production spawn should be made in early June. Medium-temperature strains or medium-temperature strains leaning toward low temperature should be selected. However, because the mycelial growth period of summer-sown shiitake is exactly in a season of high temperature and high humidity, contaminating microorganisms are difficult to control, so in recent years winter-sown shiitake has developed somewhat.

Generally, production spawn is made in late November and early December, sowing is done in late December and early January, and the bags are moved into the shed for fruiting in mid-March. Medium-temperature strains or medium-temperature strains leaning toward high temperature are mostly used.

Substrate Treatment

1. Preparation of cultivation material

The cultivation material is the substrate for the growth and development of shiitake and the material basis of its life, so the quality of the cultivation material directly affects the success or failure of shiitake production as well as the level of yield and quality. Because organic material resources differ from place to place, the cultivation materials used in shiitake production also differ.

(1) Preparation of several cultivation materials. The ingredients are calculated based on 100 kg, and increased or decreased according to the scale of production.

① Sawdust 78%, bran (fine rice bran) 20%, gypsum 1%, urea 0.3%, MP compound beneficial bacteria 0.1%, MP companion 1%. The water content of the material is 55%-60%.

② Sawdust 78%, bran 16%, cornmeal 2%, sugar 1.2%, gypsum 2%-2.5%, urea 0.3%, superphosphate 0.5%, MP compound beneficial bacteria 0.1%, MP companion 1.2%. The water content of the material is 55%-60%.

③ Sawdust 78%, bran 18%, gypsum 2%, superphosphate 0.5%, magnesium sulfate 0.2%, urea 0.3%, MP compound beneficial bacteria 0.1%, MP companion 1%. The water content of the material is 55%-60%.

Preparation of the above 3 cultivation materials: first dry-mix the gypsum and bran evenly, then dry-mix them evenly with the sawdust. Dissolve the MP compound beneficial bacteria, MP companion and urea in water first, sprinkle evenly over the material, turning with a shovel while sprinkling, and use a bamboo broom to sweep repeatedly over the surface of the material until even.

④ Cottonseed hulls 50%, sawdust 32%, bran 15%, gypsum 1%, superphosphate 0.5%, urea 0.5%, MP compound beneficial bacteria 0.1%, MP companion 1%. The water content of the material is about 60%.

⑤ Bean stalks 46%, sawdust 32%, bran 20%, gypsum 1%, MP compound beneficial bacteria 0.1%, MP companion 1%. The water content of the material is 60%.

⑥ Sawdust 36%, cottonseed hulls 26%, corn cobs 20%, bran 15%, gypsum 1%, superphosphate 0.5%, urea 0.5%, MP compound beneficial bacteria 0.1%, MP companion 1%. The water content of the material is 60%.

Preparation of the above 3 cultivation materials: weigh each ingredient according to the amount. First add water to the materials that absorb more water, such as cottonseed hulls, bean stalks and corn cobs, at a material-to-water ratio of 1:1.4-1.5, and mix well so that the material absorbs the water thoroughly; dry-mix the gypsum, superphosphate, bran and sawdust evenly, then mix evenly with the cottonseed hulls, bean stalks or corn cobs that have already been mixed with water; dissolve the MP compound beneficial bacteria, MP companion and urea in water and mix into the material, while adjusting the moisture of the material, and use a shovel and bamboo broom to turn and mix the material evenly. There must be no dry particles of material.

2. Several issues to note when mixing ingredients

Sawdust refers to sawdust from broadleaf trees, that is, hardwood sawdust. Old sawdust is better than fresh sawdust. Before mixing, the sawdust should be sieved to remove coarse sawdust and prevent puncturing the plastic bags; the degree of coarseness should be moderate, as sawdust that is too fine affects ventilation within the bag. In sawdust cultivation material, 10%-30% cottonseed hulls should be added, which has a yield-increasing effect;

however, if cottonseed hulls and corn cobs account for too large a proportion of the cultivation material, the mycelial column is likely to break when the bags are removed for fruiting. Bran and urea in the cultivation material should not be added too much, otherwise it easily causes excessive vegetative growth of the mycelium, making color turning and fruiting difficult. Bran and rice bran must be fresh, not caked, and not infested with insects or moldy. Bean stalks should be ground into a coarse bran-like form, and corn cobs ground into granules the size of beans.

The water content of shiitake cultivation material should be slightly lower than that of oyster mushroom cultivation material, generally controlled at 55%-60% in production. Slightly lower water content helps control contamination by unwanted microorganisms, but after the first flush of mushrooms has been produced, the mycelial column must be promptly supplemented with 0.1% MP beneficial bacteria liquid, otherwise fruiting will be affected. Because the raw materials differ in dryness and wetness, and in softness, hardness and coarseness, the material-to-water ratio during mixing also differs; generally the material-to-water ratio is 1:0.9-1.3, with a very large range of variation.

Therefore, in production, when a batch of material is used for mixing for the first time, after the material is mixed, its water content should be measured to determine a suitable material-to-water ratio.

① Hand test method. Take a handful of the mixed cultivation material and squeeze hard; water visible between the fingers but not dripping is sufficient.

② Drying method. Accurately weigh 500 grams of the mixed material, spread it thinly in an enamel tray, dry it at 105°C until the weight of the dry material no longer decreases, and weigh the dry material. Material water content (%) = wet material weight - dry material weight / wet material weight × 100 when mixing.

3. Fermentation of the substrate: Mix the above materials in proportion, control the humidity well, and build a pile for fermentation. The pile is generally built as a long pile 1.2-1.5 m wide and 0.8-1.2 m high, with unlimited length. The capacity of each pile should be no less than 250 kg of dry material, and preferably about 500 kg or more. When building the pile, the surroundings of the pile should be gently patted firm, and the sides of the pile should be vertical like a wall, or slightly sloped, as long as the material does not collapse, with the top of the pile arched in a turtle-back shape. After the pile is built, use a wooden stick 5 cm in diameter to first punch 1-2 rows of ventilation holes vertically downward at the top of the pile, then punch 1 row of ventilation holes obliquely and horizontally at the middle and lower parts of both sides of the pile, with a spacing of about 30 cm. The depth of the holes should reach the bottom of the pile and the center of the pile respectively. Then insert a long-handled thermometer into the pile, and cover the pile well with breathable coverings such as straw curtains, gunny bags and woven bags.

After the pile is covered, depending on the air temperature, after about 2-3 days, when the material temperature at a depth of about 25 cm in the surface layer rises to 60-65°C, start timing. After maintaining this for 12 hours, carry out the first turning of the pile. The key to turning the pile is to exchange the positions of the cultivation material in the outer layer of the pile (the dry and cool layer), the inner layer (the aerobic fermentation layer) and the bottom layer (the anaerobic fermentation layer). After turning, rebuild the pile; the requirements for punching air holes and covering are basically the same as when the pile was first built. When the pile temperature again rises to 60-65°C, still maintain it for 8-12 hours, then carry out the second turning and rebuild the pile well.

Generally 3 turnings are needed, and the pile period is about 5-7 days depending on air temperature. When the cultivation material becomes uniformly darker in color, its texture becomes soft, more white actinomycetes appear in the material, and no ammonia, foul or sour smell can be detected, the pile can be broken up to terminate fermentation. After breaking up the pile, wait until the material temperature drops to about 30°C, then it can be bagged and sown.

4. Notes during the fermentation process:

(1) Air temperature has a great influence on the fermentation process. When the air temperature is above 20°C, it is most favorable for fermentation. If the air temperature is low, the fermentation time should be extended, and special attention should be paid to keeping warm.

(2) The water content of the cultivation material has a great influence on the fermentation process and quality. When the water content is above 70%, the cultivation material will become foul-smelling or putrid and sour, and the material temperature rises slowly; when the water content is below 50%, a pile-burning “smoking phenomenon” will occur. When the above situations occur, the pile should be immediately broken up to adjust the moisture and then rebuilt.

(3) During the fermentation of the cultivation material, do not let it be exposed to direct sunlight or rain.

(4) The shape and size of the pile also affect the fermentation process. Generally, one fermentation pile should not contain less than 250 kg of cultivation material. A trapezoidal long pile is better. When there is more material, increase the length of the pile; in this way, the difference between the inside and outside of the pile can be kept small, and fermentation is more uniform.

 Bagging

1. Bag specifications: flat width 15-18 cm × 45-55 cm × 0.05 mm low-pressure polyethylene tube bags. Henan: sleeve bag: inner bag 15 cm (0.05 mm thick), outer bag 17 cm (0.01 mm)

2. Filling amount: dry material 0.9-1.0 kg, wet material 2.1-2.3 kg

3. The tightness should be appropriate: test method: hold the material bag with all five fingers and apply a little force before a dent appears; lift the middle of the material bag, and the two ends do not bend downward.

4. Handle gently

Hole Punching and Inoculation

1. Inoculation time: based on the principle of lower temperature, cool after removal from the pot to below 30°C

2. The inoculation environment is sprayed and purified with 1:10 MP compound beneficial bacteria

3. Operation method for punching holes and inoculating on the side of long bags:

The first person dips a gauze pad in a little MP compound beneficial bacteria stock solution and quickly wipes the surface of the material bag once, then uses a conical wooden stick or hollow punch to punch 3 inoculation holes at equal distances on the material bag, with a hole diameter of 1.5 cm and a depth of 2 cm, then turns it over to the other side and punches 2 more inoculation holes staggered from the holes on the opposite side;

The second person uses sterile inoculation tweezers to take out the spawn blocks and quickly put them into the inoculation holes;

The third person seals the inoculation holes well with 3.25-3.6 cm × 3.5-4.0 cm film pieces;

The fourth person carries away the inoculated material bags.

Punch holes, inoculate and seal openings at the same time, and the faster the better. If sleeve bags are used, remove the outer bag at inoculation; after punching and inoculating, do not seal the openings, but tie the sleeve bag well.

Mycelial Growth Management

1. Stack in a # shape, 4 bags per layer, 4-10 layers.

2. The mycelial growth time is about 60 d, during which the pile is turned 4-5 times. Turn it for the first time 6-7 d after inoculation, and thereafter once every 7-10 d, taking care to turn evenly from top to bottom, left to right, and inside to outside.

3. In the early stage, control the temperature at 22-25°C, and do not exceed 28°C.

4. After 15 d, tear open one corner of the film piece diagonally or prick holes at a point 1 cm inside for ventilation. After another week, if growth clearly slows, prick holes a second time at the junction of the colonies. When it is about to fill up, use a sweater needle to prick deep holes of about 2 cm.

Color-Turning Period Management

1. Standard for removing the bags: when the mycelial age reaches more than 60 days, the bag is filled with dense white mycelium, irregular small blister-like bulges appear around the inoculation holes, reddish-brown spots appear at the inoculation holes and part of the bag wall, and the bag feels elastic when picked up by hand, this indicates that the mycelium has reached physiological maturity. The optimum temperature for bag removal is 16-23°C.

2. Setting up the frame and arranging the logs

Make beds and plots in the mushroom house. Set log racks on the bed surface; the length and width of the racks are the same as the dimensions of the bed surface, with crossbars spaced 20 cm apart and 25 cm above the ground. At intervals of about 1.5 m, use bamboo strips 2-2.5 m long, bent into arches, and fix them on the log racks. Place the mycelial logs on the crossbars at an angle of 60-70° to the bed surface, with the upright logs leaning obliquely, and the spacing between logs 4-7 cm. After arranging the logs, immediately cover them with plastic film.

3. Bag removal and color turning (very critical)

For 3-5 d after bag removal, try not to lift the plastic film. After 5-6 d, short fuzzy mycelium will appear on the surface of the mycelial logs. When the fuzzy mycelium grows to nearly 2 mm, lift the film for ventilation 1-2 times a day for 20 min each time, to prompt the fuzzy mycelium to lie down and form a thin mycelial membrane, which begins to secrete pigment and exude yellow water. At this time, lift the film and spray water onto the mycelial logs, 1-2 times a day for 2 consecutive d. Generally color turning continues for one week, first from white to pink, then to reddish-brown (a glossy mycelial membrane, the formation of artificial bark), and color turning is then complete.

Common abnormal phenomena during color turning and how to handle them:

1. Color turning too light or not turning at all: if during bag removal the mycelial column is exposed to sunlight or dry wind, causing the surface of the mycelial column to become too dry, spray 0.1% MP beneficial bacteria dilution onto the mycelial column to restore the moisture of its surface, cover the film well, reduce the number of ventilations and shorten the ventilation time; ventilate 1-2 times a day for 10-20 minutes each time. If the relative air humidity in the space is too low or the temperature is below 12°C, or above 28°C, promptly take measures to increase humidity and control temperature, trying to keep the humidity in the bed at 85%-90% and the temperature at 15-25°C.

2. The mycelium on the surface of the mycelial column keeps growing vigorously and does not lie down or turn color even when it reaches 2 mm: the cause of this phenomenon is lack of oxygen; although the temperature is suitable, the humidity is too high, or the nitrogen content of the cultivation material is too high, etc. This requires extending the ventilation time, letting light shine on the mycelial column, and increasing the difference between wet and dry on its surface, forcing the mycelium to lie down. If there is still no effect, spray 3% lime water on the mycelial column, and after drying until the surface of the mycelial column is no longer sticky and slippery, cover the film again and resume normal management.

3. The mycelium dehydrates, and the surface of the mycelial column feels prickly to the touch: use water spraying to increase the relative air humidity and the moisture of the surface of the mycelial column, keeping the relative air humidity inside the film at 85%-90%.

4. About two days after bag removal, the tumor-like mycelium on the surface of the mycelial column produces bubbles and swells, and falls off in local sheets, or partially separates from the mycelial column to form a hanging shape: the main causes of this phenomenon are external force damage during bag removal or the influence of high temperature (28°C), and it may also be caused by removing the bags too early, insufficient mycelial age, and mycelium not yet mature, unable to adapt to the changed environment. The solution is to strictly control the temperature at 15-25°C and the relative air humidity at 85%-90%, prompting new mycelium to grow again on the surface of the mycelial column, and then prompting it to turn color.

5. When contamination by unwanted microorganisms is found on the mycelial column, spray it with MP beneficial bacteria at a 1:10 dilution, once a day for 3 consecutive days. After each spraying, let it dry slightly before covering the film again. If the amount of contamination is not large, you can spray the infected parts with MP beneficial bacteria stock solution. Besides bag removal and color turning, some production uses the method of pricking micropores for ventilation to turn color, and after color turning the bags are removed for fruiting. Others do not remove the bags; when shiitake fruiting body primordia appear around the inoculation holes of the bag, cut the plastic bag around the primordia with a knife to expose the primordia and carry out fruiting management. After the first flush of mushrooms is finished, the color turning of the whole bag is complete, then the bag is removed and soaked in water to produce the second flush. These color-turning methods are simple and retain moisture well; using this method for color turning in the hot season can reduce contamination by unwanted microorganisms.

Fruiting Management

After the shiitake mycelial column turns color, the mycelium is fully mature and has accumulated abundant nutrients. Under the stimulus of certain conditions, it rapidly moves from vegetative growth to reproductive growth, and fruiting body primordium differentiation and growth and development occur, that is, it enters the fruiting period.

1. Primordia induction: shiitake is a fungus that fruits under variable temperature. A certain temperature difference, scattered light and fresh air are beneficial to the differentiation of fruiting body primordia. During this period, the film covering the bed is generally removed, and the temperature of the fruiting greenhouse is best controlled at 10-22°C, with a day-night temperature difference of 5-10°C. If the natural temperature difference is small, you can also artificially enlarge the temperature difference by taking advantage of ventilation during the day and at night. Maintain the relative air humidity at about 90%. When conditions are suitable, in 3-4 days white cracks will appear in the brown mycelial membrane on the surface of the mycelial column, and mushroom buds will soon grow out. During this period, prevent the space humidity from being too low or the mycelial column from lacking water, so as not to affect the formation of fruiting body primordia. When this occurs, increase water spraying; after each spraying, dry until the surface of the mycelial column is not sticky and slippery but only slightly damp, then cover with plastic film to retain moisture. Also prevent high temperature and high humidity, to prevent contamination by unwanted microorganisms and rotting of the mycelial column. Once high temperature and high humidity occur, strengthen ventilation to lower the temperature and humidity.

2. Management during the growth and development period of fruiting bodies: after the mushroom buds differentiate, they enter the growth and development period. The temperature for the growth and development of fruiting bodies differs among shiitake strains of different temperature types. Most strains can grow and develop fruiting bodies within the temperature range of 8-25°C, with the optimum temperature at 15-20°C; under constant temperature conditions the fruiting bodies grow and develop very well. A relative air humidity of 85%-90% is required. As the fruiting bodies keep growing, respiration strengthens and carbon dioxide accumulates faster, so ventilation should be strengthened to keep the air fresh, and there should also be a certain amount of scattered light.

Summer-sown shiitake begins fruiting in autumn. In northern autumn, the sky is clear and the air is crisp, the climate is dry, and the temperature changes greatly. The mycelial column has just begun fruiting, with sufficient water and rich nutrition, and the mycelium is robust; the focus of management is temperature control and moisture retention. In early autumn the temperature is high, so the fruiting greenhouse should be covered with shading material, and ventilated and sprayed with water to lower the temperature; in late autumn when the temperature is low, increase light during the day to raise the temperature; if the light is strong and affects fruiting, hang a shade net in the middle of the greenhouse, and add an insulating curtain at night. When the relative humidity of the space is low, you can spray water with 0.1% MP beneficial bacteria, mainly spraying toward the walls and the space, to increase the relative air humidity. When the fruiting body has grown to the point where the mycelial membrane has broken, the cap has not yet fully expanded, the margin is still rolled inward, the gills have all extended and turned from white to brown, the fruiting body is eight-tenths mature and can be harvested. When harvesting, hold the mycelial column with one hand, pinch the base of the stipe with the other hand and twist it off. After the whole flush of mushrooms has been completely harvested, ventilate thoroughly once; in clear weather and dry climate, ventilate for 2 hours; in cloudy weather or when humidity is high, ventilate for 4 hours, to dry the surface of the mycelial column, then stop spraying water for 5-7 days.

Let the mycelium fully recover and grow; when the mycelium at the indentations left by harvesting turns white, replenish water to the mycelial column. The water replenishment method is to first use No. 10 iron wire to punch a hole in the center of each end of the mycelial column, reaching 1/2 of the length of the column, then punch 3 holes at equal distances on the side of the column, then arrange the columns in a soaking pool, place wooden boards on the columns, press the boards down with stones, add clean water and soak for about 2 hours, until the water has soaked through the column (the weight of the column is slightly lower than before fruiting). Columns not soaked through have insufficient water, and excessive soaking easily causes the column to rot; both affect fruiting. After water replenishment, rearrange the columns in the bed and repeat the previous primordia induction and fruiting management method, preparing to produce the second flush. After the second flush is harvested, again stop water and replenish water, repeating the previous management; generally 4 flushes are produced. Sometimes the moisture of the mixed material is on the high side, and when the temperature and humidity during fruiting are suitable, the water loss of the column during the first flush is not great, so instead of the soaking method, you can after the first flush is harvested stop water for 5-7 days, and after the mycelium resumes growth, directly spray a heavy watering on the column to let it absorb naturally and increase its water content, then repeat the previous primordia induction and fruiting management; after the second flush is harvested, then soak the column to replenish water. The soaking time can be appropriately longer. Thereafter, each time a flush is harvested, replenish water once.

In northern winters the temperature is low, fruiting bodies grow slowly and yields are low, but the mushrooms are thick-fleshed and of good quality. The focus of management in this season is keeping and raising warmth: increase light during the day, add straw curtains at night, and if conditions permit, make a fire to raise the temperature; ventilate at noon, and try to keep the temperature in the greenhouse above 7°C. You can spray water on the space and walls to regulate humidity, and spray less water directly on the mycelial columns. If the temperature is too low for fruiting, control the relative humidity of the greenhouse at 70%-75%, and maintain the mycelium to keep it through the winter.

The spring climate is dry and windy. At this time the mycelial columns have fruited through autumn and winter; because the columns have lost much water and have insufficient moisture, mycelial growth is also not as vigorous as in autumn. The focus of management is to replenish water to the columns, soaking for 2-4 hours, frequently spraying water on the walls and space, and keeping the relative air humidity at 85%-90%. In early spring, pay attention to keeping and raising warmth; ventilation should be appropriate, and can be done after spraying water; control the ventilation time, and do not cause temperature and humidity to drop.

Note: Water replenishment nutrient solution: MP compound beneficial bacteria 0.1%, potassium dihydrogen phosphate 0.1%, gene vitality peptide 0.1%

Winter-Sown Shiitake Bag Cultivation Method

When shiitake is sown in summer, it is exactly the season of high temperature and high humidity; inoculation and mycelial culturing are difficult, and contamination by unwanted microorganisms or high-temperature burning of the mycelium easily occurs. When shiitake is sown in winter, medium-temperature and medium-to-high-temperature shiitake strains should be used. Start making mother spawn in late October, make stock spawn in early November, make cultivation spawn in late November and early December, and sow in January. Use 17 cm × 35 cm plastic tubes as cultivation bags; the operation methods for mixing material, bagging, sterilization and inoculation are basically the same as for summer sowing. Choose a room or greenhouse that is easy to warm and keep warm as the bag culturing site. The culturing site must be disinfected in space before the bags are brought in. The bags are stacked in rows in a “#” shape with the inoculation holes facing sideways, 6-7 layers per row, 4 rows as one block, with unlimited length, and walkways left between blocks. At the beginning, control the room temperature at about 25-26°C, and ventilate once every 3 days at noon when the temperature is high. When the bags have been cultured for 13-15 days and the mycelium at the inoculation holes has grown to a diameter of more than 8 cm, carry out the first bag turning and micro-hole punching.

Before turning the bags, spray 2% Lysol or use an oxygen atom disinfection device to disinfect the space. Exchange the high-temperature bags in the middle two rows of each block with the bags on the two sides, and exchange the bags on the two sides to the middle, so that the temperature difference among the bags is not great and the mycelium grows uniformly. When turning the bags, remove the bags contaminated by unwanted microorganisms, and at the same time, for bags free of contamination, punch micro-holes on the parts with mycelium at 2 cm from the mycelial growth front, with a micro-hole depth of 1 cm, punching 3-4 in the mycelium at each inoculation hole.

After the first bag turning and hole punching, the amount of mycelial growth increases; at this time control the room temperature at about 24°C. At this time ventilate once every 2 days at noon. After another 12-13 days, carry out the second bag turning, and punch a ring of micro-holes on each patch of mycelium at 2 cm from the mycelial growth front, about 5-6 holes, with a hole depth of about 2 cm; at this time control the room temperature at about 23°C. Pay attention to shading throughout the whole culturing process.

For bags with specifications of 17 cm × 35 cm, if inoculated at 4 points, they generally fill the bag in about 45 days. Continue culturing; when the surface of the mycelial column in the bag swells and tumor-like bodies appear over 2/3 of the area, the bags can be moved into the fruiting shed, and the bags removed for color turning and fruiting. Generally in mid-to-late March the bags can be moved into the greenhouse for fruiting. First make beds in the greenhouse, 1-1.2 m wide and 15-20 cm deep. The greenhouse should be disinfected in space with sulfur or formaldehyde, and lime powder scattered on the ground. Spread a layer of furnace ash or sand on the bed surface, remove the plastic bags from the well-grown bags in the greenhouse, and stand the mycelial columns in the bed with a spacing of 2 cm; fill the gaps between the columns with soil (60% garden soil + 40% furnace ash, sun-dried, then adjusted with 5% formaldehyde water until it forms a ball in the hand and breaks apart when dropped, piled up, covered with film, left to cure for 2 days before use; fertile loam from 10 cm below the surface can also be used).

The top of each mycelial column exposes 2 cm above the soil layer, and use a soft long-bristled brush to brush off the soil adhering to the exposed part of the column. Arch bamboo strips over the bed, cover with plastic film, keep warm and moist, and turn color. The color turning of winter-sown shiitake is in late March, when the temperature is on the low side, the relative air humidity is small, and it is windy; the focus of management is keeping warm, retaining moisture and light ventilation. Fruiting management is the same as before. After the first flush is harvested, ventilate the greenhouse thoroughly for 1 hour, stop spraying water for 4-5 days, then spray a heavy watering into the bed to replenish the water content of the columns. After April, management should pay attention to shading, cooling and pest prevention. The advantage of this cultivation method is that the columns in the soil can replenish water and part of the nutrients at any time, saving the process of soaking the bags to replenish water. At the same time, note that because the columns only fruit at the top, the fruiting area is relatively small; if the fruiting density is high, the mushrooms often crowd and deform each other, causing a decline in quality, so when the buds are too dense, thin them promptly to ensure mushroom quality. In addition, the fruiting bodies are very close to the ground and easily pick up sand, which also affects their commercial quality; when spraying water, spray gently and finely, and do not let soil splash onto the fruiting bodies.

Harvest

1. Generally, harvest when the cap has expanded six or seven tenths, the cap margin is still rolled inward, and the partial veil has just recently broken.

2. Harvest the early-maturing ones first and the late-maturing ones later.

3. Harvesting method: press the bag with one hand, pinch the base of the stipe with the other hand, gently rotate and then pull it up together with the stipe.

4. After harvesting, do not pack them in large baskets or gunny bags.