Practical experience and key technical points for shiitake mushroom cultivation on cut logs

Among shiitake mushrooms, those grown on cut logs are especially popular with consumers. The author has been engaged in cut-log shiitake cultivation for decades, and now shares the practical experience as follows.

1. Selection of tree species: apart from oily and aromatic tree species such as pine, Chinese fir and cypress, more than 200 tree species are suitable, including white oak, Mongolian oak, ring-cupped oak, maple, fragrant tree, true chestnut, chestnut and wild walnut.

2. Felling: trees can be felled from the Winter Solstice to Awakening of Insects, with felling during the "nine-day" cold period being best, and no later than Pure Brightness at the latest. This is because during this period the trees are dormant, the bark and xylem are tightly joined, nutrients are rich, contaminating microorganisms are few, and after felling the stumps sprout new shoots readily.

3. Cutting into sections: it is best to saw them apart; the length should be flexibly determined according to the size of the tree, and should be convenient for handling, generally 1.0-1.2 m.

4. Inoculation tools: generally a leather punch with a diameter of 10-12 mm is used; an electric drill can also be used to make the holes, and the person placing the spawn should also prepare a small iron hammer.

5. Hole punching: generally a 1 m long log section (with 12 cm left at the small end) can take 4 rows, with 9 holes per row; the hole depth should be more than 1 cm into the xylem after breaking through the bark. If there are breaks in the bark, scars or knots, 1 extra hole can be added.

6. Inoculation: note that holes should be punched and inoculated at the same time; never punch holes in the morning and inoculate in the afternoon, still less leave it overnight, and do not inoculate in heavy rain or under scorching sun. Inoculators are required to wash their hands first, then put part of the powdered spawn into the hole, then put in the small wooden block spawn and tap it tight with a small iron hammer. The inoculation amount should be large; never skimp on spawn.

7. Stacking for mycelial colonization: methods such as the "mountain" shape, the firewood-stack style and the upright style can be used, with the upright style (small end on the ground) being best. In case of low temperature or rainy days, plastic film can be used as a cover, but attention must be paid to ventilation; cover the stack with weeds and branches and leaves to protect against sun and rain. The colonization period is about 50 days; note that "dark colonization" is required, and the site must be clean and dry. It is even more ideal if inoculation, colonization and mycelial resting can be done on the mountain on the spot.

8. Mycelial resting: after about 50 days of inoculation the stack should be turned to check whether the spawn has survived. The small wooden spawn plugs can be pulled out for inspection: white is good, yellow indicates dryness, and black means dead (if the surface of the spawn has already turned white, there is no need to pull plugs for inspection again). Where dead spawn is found, re-inoculation can be done to make up for the loss. Then stack in the "#" shape or the "tile-overlapping" style, taking care to keep a certain distance between logs to allow ventilation. Once in the mycelial resting stage, branches and weeds are still needed as cover to keep it dark and prevent scorching sun; afterwards it is best to turn the stack once every 1-2 months. In summer, with high temperature and drought, mushroom yards with the means to do so should spray water to lower the temperature (do not spray at noon), keep the stack "alternately dry and moist", and pay attention to pest and disease control. The whole mycelial resting period is about 8 months to one year.

9. Fruiting management: after the logs have gone through spring, summer and autumn, by late autumn and early winter, when the average temperature drops to about 15°C, "signal mushrooms" will grow if there is a certain amount of rainfall. At this time the mushroom yard is best kept at "six wet, four dry", the relative air humidity is best at about 85%-90%, and the light should be kept at "six shade, four sun".

10. Racking the logs for fruiting: to facilitate the growth and picking of shiitake fruiting bodies, rack the logs for fruiting at the appropriate time. According to actual conditions, use different racking forms such as the "herringbone" and the "tile-overlapping" style. When racking, place the small end of the log on the ground and the large end upward; this can prolong the life of part of the bark and raise the fruiting rate. Prevent racking the logs for fruiting before they have reached physiological maturity.

11. Picking: shiitake mushrooms can be picked when they reach seven to eight tenths ripe and the edge of the cap is still incurved in the "gong rim" shape. Picking is best done on sunny days; when picking, pinch the base of the mushroom stem with the hand and twist it off gently, and the mushroom foot must be picked clean.

12. Drying: "The fragrance of shiitake comes from baking." After picking, place the shiitake mushrooms one by one in the baking tray with caps up and stems down, and bake them the same day they are picked. The baking temperature should be low first and then high: at the beginning it must not exceed 40°C, raise it by 5°C every 3-4 hours, and do not exceed 65°C at the highest. Once the stems are hard, they can be packaged for sale.