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When breeding most mushrooms, grain mycelium purchased from special farms is used. To grow mushrooms, the mycelium must be stored under certain conditions, and its quality must be checked before planting. But, even with excellent planting material, one cannot do without special preparation of the substrate - it requires heat treatment and sterilization.

Storing the mycelium of oyster mushrooms, champignons and other mushrooms in the refrigerator

Currently, in the cultivation of champignon, oyster mushroom and shiitake, vegetative sowing is mainly used with the help of the so-called sterile grain mycelium. It is a boiled and sterilized grain, mastered by a cultivated mushroom mycelium purified from competitors. Non-sterile grain mycelium is not used for growing mushrooms at home, because in non-sterile conditions, the grain is quickly attacked by putrefactive bacteria and mold. Grain mycelium is suitable for the propagation of most fungi. On grain of wheat, barley and millet, oyster mushroom and shiitake mycelium is produced, on grain of wheat and rye - mushroom and ringworm mycelium. Grain mycelium for growing mushrooms has a good supply of nutrients. The mycelium produced by a large company, as a rule, guarantees the successful cultivation of the mushroom indicated on the package.

Grain mycelium is sold in air-filtered plastic bags containing 8 kg of mycelium. The filter is needed to supply oxygen and to protect the mycelium from mold and other competitors. If stored improperly, the mycelium of champignons and most other mushrooms dies when the air temperature rises above 30 ° C. And at a negative storage temperature, the mycelium freezes and loses quality.

Long-term storage of mycelium for oyster mushrooms and other mushrooms is permissible at an air temperature of +2 ° С. Packages must be packed with air gaps, because the mycelium heats up as a result of its own vital activity. At home, storing grain mycelium is possible in a household refrigerator, but not in a freezer. It should be borne in mind that, although it is permissible to store mycelium in modern household refrigerators, it should be borne in mind that in a chamber with automatic defrosting, the temperature periodically fluctuates from +1 to +10 ° C. Therefore, with a long shelf life of the mycelium of oyster mushroom and shiitake, a hard crust of mycelium and rudiments of fruiting bodies are formed inside the bag, and the mycelium of champignon and ringworm quickly deteriorates.

When buying mycelium in small packages, make sure there is an air filter or holes in the bag for air. Without this, the mycelium will quickly rot, and with holes without a filter, sooner or later it will become infected with mold.

Even if you have followed all the storage conditions for the mycelium of mushrooms, you need to check its quality before planting. This can be done in the following way. Prepare a solution of a teaspoon of sugar in a glass of boiled water. Fold the toilet paper in several layers in a 5x5 cm square. Clean toilet paper is sterile, unlike napkins. Liberally moisten a paper square with sugar solution, wring it out and place in a Petri dish or on a clean saucer. Place a few grains of grain mycelium from the purchased bag and cover with a petri dish or glass. At room temperature, a week later, a white edge of mycelium growing in the air should appear on the grains or on another substrate sold to you as mycelium. There should be no colored spots. This sprouted mycelium should be free of mold stains a few months later. So you can check not only grain, but also any other mycelium.

Reproduction of mycelium of oyster mushrooms and other mushrooms at home

Purchased high quality mycelium can be multiplied by yourself. For the reproduction of the mycelium of fungi, the wheat grain must be boiled over low heat for 20-25 minutes. It cannot be digested. It is important that the core of the grain remains white. Then the grain must be dried on the table, stirring it with a spatula for 30 minutes. Can be dried under a fan. After that, it should have a humidity of 50-53%. For drying, you can add chalk and gypsum to the grain - 5% of the grain weight. The grain prepared in this way is poured into two-liter glass jars at the rate of 1 kg per jar. When breeding oyster mushroom mycelium at home, grain should occupy less than half the volume of the jar. Jars of grain are tightly closed with lids with a sterile cotton plug and sterilized together with the grain in a saucepan with boiling water or in an autoclave. For the cork, a hole with a diameter of 3 cm is made in the center of the lid. To prevent boiling water from wetting the cotton cork, wrap the lids with aluminum foil or craft paper, which is tied around the neck of the jar with twine. Cut off the excess edges of the paper.

When mycelium multiplies, put a rag under the jars and pour cold water 3-4 cm below the lids. To sterilize the grain, the jars must be boiled twice for 2 hours at intervals of a day. In the interval between boiling, the jars should be at room temperature. When using an autoclave at a temperature of +120 ° C and an overpressure of 1.0 atm. it is enough to sterilize once within 2.5 hours. Sterilization in a household autoclave at +110 ° C is acceptable.

Without removing the lids, jars with grain must be cooled to + 22 ... + 55 ° С and transferred to a sterile box or to another clean room for seeding the grain with the sterile mycelium at your disposal. During inoculation (inoculation), the lid with the filter must be removed, a tablespoon of mycelium must be put in the jar and again closed with a lid with a cotton stopper, then with kraft paper and tied. Then the jars must be shaken to evenly mix the mycelium with the grain and placed in a clean room with an air temperature of + 24 ... + 26 ° C for overgrowing.

The incubation time in a jar of grain is 14 days for oyster mushroom mycelium propagation, for shiitake - more than 30 days. The incubation period for other fungi takes the same period. After 7 days of growing the mycelium, the contents of the jars must be shaken so that the grain is not too strongly held together by the mycelium, and the overgrowth of the grain is uniform.

After the grain in the jars is completely overgrown, you can transfer the mycelium from the jars to plastic bags.

Substrate for growing oyster mushrooms and other mushrooms

Good yields of oyster mushrooms, shiitake and other woody mushrooms can be grown on a free-flowing substrate made from chopped straw, cotton wool, sunflower seed husks, or ground twigs. Nutritional supplements can be added to such a growing substrate for mushrooms, and heat treatment of the substrate will free it from mold. The granular structure provides oxygen access to the developing mycelium, therefore, the development of such a substrate occurs several times faster than the development of dense wood. To create a high concentration of carbon dioxide required for mycelium growth, the substrate at home is placed in plastic bags with air-permeable plugs or with perforations.

The basis of the substrate is called the material that makes up more than 50% of its total mass. The nitrogen content in the main materials of the substrate is as follows: sawdust - 0.1%, flax fire - 0.5%, straw - 0.6%, husk - 0.7%, cotton wool - 0.7%, ground branches - 0 , 7% (all with respect to dry weight). To achieve the optimal nitrogen content (0.7-1.0%), the substrate for mushrooms can be made cereal by adding grain or bran to it in an amount of 10-20% of the dry mass of the substrate. The substrate must be moistened so that its moisture content is in the range from 45 to 70%.The optimum moisture content of the substrate is 60%.

The moisture content of the substrate for fungi (W%) is the ratio of the mass of water in it to the mass of the substrate, expressed as a percentage. The moisture content is determined as follows: 100 g of the substrate is kept in a drying cabinet or oven for 6 hours (up to constant weight) at a temperature of + 110 ... + 120 ° C (not higher than 150 ° C to prevent charring of the dried components).

The difference between the weight of a wet and dry sample, expressed in grams, will be numerically equal to the moisture content of the substrate in percent. You can dry a 100 g sample in a microwave oven instead of an oven. The microwave is adjustable to 350-400 W. Warm-up mode: warming up for 4 minutes; pause 2 minutes; warming up for 4 minutes; pause 2 minutes; warming up 4 min.

Mushrooms - aerobic organisms, which consume oxygen in the air and emit carbon dioxide. Therefore, the main parameter of the substrate base for the mycelium of fungi is its permeability to air: the structure of the substrate should be loose, and the shell of the substrate block (polyethylene bag) should have an opening for mycelium "breathing". The permeability of a moist substrate to air decreases sharply with a decrease in the particle size of the substrate base and, especially, with waterlogging of the substrate, when zones filled with free water appear in it. The diffusion coefficient of oxygen in water is tens of thousands of times less than in air. Therefore, waterlogging of the substrate for oyster mushrooms and other mushrooms creates anaerobic conditions in it, in which the mycelium cannot exist.

Processing when preparing a substrate for mushrooms at home

The best material for the future substrate mycelium is small chips from ground fresh branches of hardwood. If you cannot use all the raw materials prepared at once, you need to grind the branches and then dry them at a high temperature in an oven or in an oven. From 1000 g of fresh branches, 500-600 g of dry ones will turn out. Instead of chopped branches, you can use chopped straw that has not been in the rain, flax fire or sunflower husks. The next step is to prepare the required number of clean three-liter cans. Punch a round hole 1–2 cm in diameter in the plastic jar lids. Wash lids and jars thoroughly. Insert sterile cotton plugs (rolled cotton wool pieces) tightly into the holes in the caps. When heat-treating the cans, place the caps with corks in a clean plastic bag.

After preparing the substrate in the amount necessary to fill one or more 3-liter containers, transfer it to jars. Compact the substrate so that it does not reach the neck of a few centimeters. Pour boiling water over the substrate in the jar so that the jar does not burst. After absorbing, add boiling water to completely cover the substrate. Close the jars with lids with holes to drain the water, but do not drain the water immediately. Leave the jars of boiling water to cool slowly at room temperature for 2-3 hours. Turn the jars over, drain the water and leave upside down for a day. During this time, the water will drain from the cans, and not dead mold spores in the substrate will germinate and become defenseless against a repeated increase in temperature. This method is called fractional substrate pasteurization.

When preparing the substrate at home, weigh each jar of moistened contents on a scale. For heat treatment of the substrate for oyster mushrooms and other mushrooms, cover the cans with aluminum foil or a tin lid (leaking). Place the jars in any thermal oven or oven for 3 hours at 80 ° C.

Let the jar cool to room temperature and weigh it again. If the jar with the substrate has lost more than 20% in weight during heat treatment, bring the weight of the jar to 80% of the original by adding boiled water to the substrate. Remove the aluminum foil and close the jar with a clean polyethylene lid with a cotton stopper. The substrate is now ready for sowing with mycelium.

A simpler method of heat treatment of the substrate is called xerothermal. This is followed by the preparation of the substrate soaked to the desired moisture content in the amount necessary to fill one or more three-liter cans. Transfer it to jars.

Compact the substrate so that it does not reach the neck - a few centimeters. Weigh the substrate jars. Place the jars in an oven preheated to 110 ° C for 2-4 hours so that all the water from the substrate has boiled away, cool the jars and pour clean boiled water into the substrate in such an amount to restore the weight of the substrate, which was before heat treatment. Close the jar with a clean polyethylene lid with a cotton stopper. The substrate is now ready for sowing with mycelium.

Processing the substrate of oyster mushrooms and other mushrooms in the garden

With clean, mold-free raw materials, pasteurization can be carried out only once. In the garden, you can pasteurize the substrate in a 200-liter barrel over a fire. Place the barrel on concrete blocks or bricks. Pour 50 liters of water into it. Above the water, on bricks placed vertically inside the barrel, insert a round (barrel-shaped) mesh or grate.

After preparing the substrate for the mushrooms of the desired composition and the desired moisture content, fill it with polypropylene bags, leaving part of the bag empty to tie a rope around its throat. You can use “rustling” bags made of low pressure polyethylene. The more resilient HDPE bags that do not rustle are not suitable for this. They will collapse when boiled. More expensive freezer bags are also suitable. Insert a piece of cotton wool or synthetic winterizer into the throat of the bag as a breathable cork. Pull the string around the throat of the bag around the stopper. Place the substrate blocks in several tiers on the grid with the cork upside down. Place the lid on the barrel and leave the barrel with the substrate for a day or more to allow mold spores to germinate in the substrate. The next day, light a fire under the barrel and boil the water for 6 hours in a row. By the next morning, the substrate in the barrel will cool down. To “seed” the substrate, untie the bag, remove the cork, check that the temperature of the substrate is below 30 ° C, add the mycelium, then reinsert the cork and tighten the neck of the bag with twine.

When growing exotic mushrooms (shiitake, maitake), for greater reliability, it is necessary to carry out double fractional pasteurization. The sequence of operations for double fractional pasteurization is as follows. Bags with a substrate soaked to the desired moisture content, closed with a synthetic winterizer or cotton stopper, are kept at room temperature for 24 hours, then placed in a "Chinese barrel" over the fire, pasteurized at a temperature of + 80 ... + 100 ° C for 3-6 hours, depending on the volume of the bag. After that, they are left in a barrel to cool for 16-24 hours, then the fire is again kindled and a second pasteurization is carried out.

In the same way, pasteurization can be carried out in a sauna or in any other bath at + 80 ... + 90 ° C.

Preparation of substrate for oyster mushrooms and other mushrooms: sterilization

The basis of any autoclave is a sturdy container with a lid that can withstand excess pressure of water vapor inside and is equipped with a valve for venting steam in case of dangerous excess pressure. It is believed that when preparing the substrate for oyster mushrooms and other mushrooms in an autoclave, complete sterility is achieved at +134 ° C - all organisms known on earth die. Microorganisms capable of harming cultivated mushrooms die at +120 ° C. Industrial autoclaves designed for mushroom growing operate at an excess pressure of 1 atm, which ensures the processing of the substrate at +120 ° C with "flowing steam". This allows the mushroom substrate to be completely sterilized.

A few words about what a "flowing steam" treatment is. From the steam generator, steam is fed into the autoclave container, where the substrate is located in unclosed containers or in non-tightly closed bags.It is possible to periodically bleed off a part of the steam, ensuring that new portions of it enter the autoclave. This wet substrate treatment ensures complete sterilization. In this case, all areas of the substrate are treated with steam, and not dry air. This is very important as dry spores of some molds and bacteria remain viable at temperatures of +160 ° C.

Currently, online stores offer various options for household autoclaves designed for sterilizing canned food at home. They are similar to our "Chinese barrel" on the fire, but they work at an increased steam pressure, ensuring the processing of canned food or, in our case, the substrate at a temperature of +110 ° C. Packages or jars with the substrate are placed inside a household autoclave on a grate over boiling water. This is not a "flowing steam" treatment and not a complete sterilization of the substrate, but such a treatment is quite sufficient for growing any mushrooms in the backyard.

The selected substrate must be mixed in a bowl with additives, if any, and with water in the amount necessary for the substrate to reach the required moisture content. Transfer the substrate to packages. Close the bags with cotton or synthetic winterizer stoppers and place in an autoclave. Better yet, simply put the open bags with the substrate in the autoclave and put cotton plugs and twine, which are not tightly wrapped in aluminum foil, into the autoclave.

Close the autoclave lid, set the automation to the desired temperature and processing time and follow the instructions attached to the autoclave. The presence of automatic control of the autoclave allows you to fill and turn it on in the evening, and in the morning to take out the bags with the cooled substrate from the autoclave and inoculate the substrate with mycelium. When manually operating the autoclave, before turning on, make sure that there is water in it and control its operation, focusing on the thermometer readings.