Pholiota nameko

Phoiota nameko is one of the most popular cultivated mushrooms in Japan, closely ranking behind Shiitake and Enokitake. This mushroom has an excellent, flavor and texture. P. nameko would be well received by North Americans and Europeans if it were not for the thick, translucent, glutinous slime covering the cap. (This mucilaginous coat is common with many species of Pholiota.) Although unappealing to most, this slime soon disappears upon cooking and is undetectable when the mushrooms are served. This mushroom is a superb edible which can be grown easily on sterilized, supplemented sawdust, and/or logs.

Mycelial Characteristics: Whitish, longitudinally radial, becoming light orangish or tawny from the center as the mycelium ages. On sterilized grain the mycelium is densely cottony white and becomes speckled with yellowish to orangish zones at maturity.

Microscopic Features: This mushroom produces cinnamon brown spores.

Suggested Agar Culture Media: Malt Extract Agar (MEA), Malt Yeast Agar (MYA), Potato Dextrose Yeast Agar (PDYA), and Dog Food Agar (DFA).

Spawn Media: Grain spawn throughout.

Substrates for Fruiting: The supplemented sawdust is recommended. Arita recommends that no more than 10% rice bran be used as a supplement for oak hardwood formulations. Some have found that 20% rice bran supports a more massive first flush and second flush when using Alnus rubra (ren alder). Arita also found that the addition of 15% rice bran was the optimum if using conifer sawdust ( Pinus densiflora - Asian Pine and Cryptomeria japonica - Japanese Cedar as the base substrate.) This is one of the few gourmet mushrooms that will give rise to substantial fruitings on conifer wood.

Yield Potentials: Fruitings, on first flush, give an average of slightly more than 1 lb. of mushrooms from a 5 lb. block of hardwood sawdust supplemented with rice bran.

---Growth Parameters---

Spawn Run:

• Incubation Temperature: 75-85* F (24-29* C)
• Relative Humidity: 95-100%
• Duration: 2 weeks
• CO2: >5000 ppm
• Fresh Air Exchanges: 0-1
• Light Requirements: n/a

Primordia Formation:

• Initiation Temperature: 50-6-* F (10-15.6* C)
• Relative Humidity: 98-100%
• Duration: 7-10 days
• CO2: 500-1000 ppm
• Fresh Air Exchanges: 4-8 per hour
• Light Requirements: 500-1000 lux

Fruitbody Development:

• Temperature: 55-65* F (13-18* C)
• Relative Humidity: 90-95%
• Duration: 5-8 days
• CO2: 800-1200 ppm
• Fresh Air Exchanges: 4-8 per hour
• Light Requirements: 500-1000 lux.

Cropping Cylce:

• Two crops in 60 days, 10-14 days apart.

Comments: This mushroom is more sensitive to moisture and carbon dioxide levels that most. For indoor cultivation, a precise initiation strategy is called for. It is preferred not to use a casing layer as it promotes contamination, makes cleaning of the mushrooms tedious, and is unnecessary with good environmental controls in the growing room.

Should a casing layer not be applied, the block of supplemented sawdust must be exposed to a "condensing-fog" environment during the primordia formation period. If the aerial mycelium suddenly dehydrates, and dies back, surface primordia will be prevented and no crops will form. In this event, the cultivator mush either roughen the surface of the block and/or apply a moist casing layer, two second-choice alternatives.

To initiate mushroom formation, temperatures are lowered to the 50-60* F (10-15* C) range, carbon dioxide levels are lowered, relative humidity is increased to 98-100% rH, light levels are increased to >500 lux, and the surface mycelium is frequently misted with a fine spray of water. Approximately a week after initiating, orange streaks of slime form across the exposed surface of the mycelium. It is essential that the cultivator encourages the formation of this marmalade-looking goop. Soon thereafter, populations of primordia form and emerge within this overlaying, glutinous mass. So elastic is this material that it can be stretched more than 6 inches with each pull. This glutinous layer acts as a moisture bank promoting mushroom formation and development. Should this layer collapse due to dehydration. The primordia are at risk of aborting.

Rather than removing the entire polypropylene bag, it is recommended that most cultivators cut off the top portion of the incubation bag, leaving 3-4 inch side walls of plastic surrounding the exposed, upper surface of the sensitive mushroom mycelium. These plastic walls will help collect moisture, enhancing primordia formation. If done properly, the mushroom stems will elongate to exactly the height of these walls, facilitating harvest.

Using this casing-less approach, the second flush will be poor unless the surface is roughened to expose viable mycelium. A paddle with extruding nails or a wire brush serves this purpose well. Once the surface layer is torn apart, humidity is again raised to achieve the condensing-fog atmosphere. Soon thereafter (4-7 days), the mycelium becomes aerial, fuzzy, regenerates the orange slime layer, giving rise to another break of mushrooms. To achieve a third flush, its is recommended to turn the block upside down, roughening its surface, and following similar strategy to that described above. Fourth and fifth flushes are usually not substantial.

The advantages of not using a casing layer are: less work; less risk of green mold (Trichoderma) contamination; and the harvested mushrooms are fee of debris. Because of the glutinous nature of the P. nameko fruit bodies, casing debris readily adheres to, and is difficult to remove from the harvested mushrooms and your fingers.

(Information taken from Growing Gourmet and Medicinal Mushrooms, Paul Stamets)