Cultivation of Shiitake on Synthetic logs
Lentinula edodes
Strain selection
- Low temperature 10°C
- mid temperature 10-18°C
- high temperature 20°C and above
- wide-range temperature 5-35°C (e.g. strain, China-Stamets-2)
Sources of Spawn in North America
Fungi perfecti Paul Stamets P.O. box 7634-MGN Olympia, WA 98507, USA Voice: 1-800-780-9126; 360-426-9292 Fax: 360-426-9377 www.fungi.com Field and Forest Products Joe Krawczk N3296 Kozuzek Peshtigo, WI 54157, USA Voice: 1-800-792-6220; 715-582-4997 Fax: 715-582-0181 www.fieldforest.net Mushroom People Frank Michael Box 220 Summertown, TN 38483, USA Voice: 1-800-386-4496 Fax: 1-800-692-6329 www.mushroompeople.com Western Biologicals Bill Chalmers P.O. Box 283 Aldergroove, BC VOXIAO Canada Voice and Fax: 604-856-3339Source of polypropylene and polyethylene cultivation bags
Unicorn Imp. & mfg. Corp. Lou Hsu P.O. Box 461119 Garland, TX 75046 Telephone: 1-972-272-2588 Fax: 1-972-272-8883 www.unicornbags.comSubstrate selection
Selection of the tree species for sawdust cultivation should proceed with caution. Fresh sawdust without aging by fermentation can be used for production of shiitake only if it is from high quality tree species, such as those graded 4, excellent by FAO (Oei 1996). Oak, chinkapin, hornbean, sweetgum, poplar, alder, ironwood, beech, birch. It is always preferrable not to ferment but age the sawdust for 3-4 weeks. Periodically turn the pile to air and cool the pile.Substrate formulation
Table 1. Formulation of sawdust-based substrates for shiitake cultivation.| Wu, 1993 | Stamets 1993, p.162 |
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Water content
Water should be mixed into the substrate to about 48-50 percent, and not 60% as suggested several years ago. Water should not appear at the bottom of the bag at anytime.
Bag Filling
Bags are filled either by one of the following methods :- Semi automatic filling by a travelling pipe which come to one position to be filled and to a second position to discharge into a bag.
- Bag folding before autoclaving. After bags are filled below filter, the remaining bag is folded.
- Automatic form seal machine. See Automatic FFS Machines.
Substrate sterilization
Sterilization depends on bag size and, nature and amount of the substrate. For 2-3 kg. Sawdust-based substrate in polypropylene bags, sterilize in autoclave for 2-4 hours at 121°C.(use as a reference only). Initially during trials, it is always necessary to tract the temperature in various parts of the autoclave as well as in the bagged substrate by insertion of a thermocouple inside the substrate. After the substrate reach 121°C, it is necessary to maintain at 121°C for 30 minutes. When cooling, allow HEPA filtered air to replace vapor in the autoclave.Spawning
In general, through spawning (spawn thoroughly mixed with the entire substrate) in larger bags is used in US. In this case, fill the bag with sawdust to a level below the filter. Through spawning gives a much faster growth rate. Heat-sealed bags (with microporous breathing filters), usually UNICORN Type 14 ( 8 x 5 inch foot print x 19 inch high) insert required amount of spawn, and seal the top with impulse sealer. Bags partly filled with the substrates, allow the manipulation of mixing the spawn with the substrate by shaking mechanically or manually After thoroughly mixing the spawned bag, it is placed in a incubation room at about 23°C.
Management of Growth Parameters
Check the characteristics of your shiitake strain, especially fruiting temperature and adjust accordingly. The following is adopted primarily from Stamets (1993) for strain China-Stamets-2, a strain with a broad range of tmeperature for fruiting. This strain can be fruited at either cold temperature* or warm temperature**. See Table 2 for detail in growth parameter management for spawn fun, induction of primordia and fruiting development.
Table 2. Growth parameter management for cultivation of Lintinula edodes (shiitake).
Tolerate
| Growth Period | Spawn Run | Induction of Primordia | Fruiting Development | Comment | ||
| Cold Strain | Warm Strain | Cold Strain | Warm Strain | |||
| Temperature | 21-27°C (70-80°F) | 10-16°C* (50-60°F) | 16-21°C** (60-70°F) | 16-18°C* (50-70°F) | 21-27°C** (60-80°F) | same all strains temperature fluctuation |
| Humdity | 95-100% R.H. | 95-100% R.H. | 60-80% R.H. | |||
| Time | ca. 1-2 month | 5-7 days | 5-8 days | Strain dependent | ||
| CO2 | >10,000 ppm | <1000 ppm | <1000 ppm | Tolerate | ||
| Air Exchange | 0-1/hour | 4-7/hour | 4-8/hour | |||
| Light | 50-100 lux | 500-2000 lux | 500-2000 lux | At 370-420 nm Stem elongation (green to uv) when <500 lux | ||
Observation Of How The Shiitake Mushroom Grows
Spawn run (mycelial growth and maturation)
All shiitake strains show optimal mycelial growth (spawn run) at 25°C. The duration of spawn run is usually 1-4 months, depending on strains and methodology. Some light in the day/night cycle towards the end of the spawn run is conducive to the induction of primordia. However, it could be difficult to judge the timing for lighting during spawn run. Different approaches can be used, such as short exposure to light, e.g. 4 hr./day-night cycle (Royse 1997), or use a low level of light, e.g. 50-100 lux (Stamets 1993). When shiitake substrate is fully colonized by the white mycelia, it does not mean that the block is ready for fruiting. A mycelial maturation stage is required. There are 5 stages of mycelial growth (Oei 1996, Wu 1993):
- Mycelial growth of normal spawn run: enzymes are produced to degrade components in the complex substrate, such as cellulose, hemicellulose and lignin.
- Mycelial coat formation: A thick white mycelial coat on the substrate surface is formed 2-4 wks. after inoculation (spawning) in most strains. Very thick coat can be formed at high CO2 level.
- Mycelial bump formation (blister stage, or popcorn stage): clumps of mycelia are developed in some strains. Primordia are produced at the tips of some of these bumps. However, most bumps are aborted. Fluctuation of temperature and high CO2 concentration encourage bump formation. Over-developed bumps may puncture the bag. Bumps can also be susceptible to contamination by weed molds. Some aeration should be provided whem bumps are formed. Remove bags before pigmentation, or browning (Royse 1997). Timing of bag removal is crucial. Yield can be effected if bag removal is too early or too late. Maintain 60-70-% R.H. to avoid contamination.
- Pigmentation and coat-hardening stage (browning and bark-formation stage): Browning outside of thebag is encouraged in U.S., in contrast to browning inside of the bag. Some growers remove the bag when 1/2 to 1/3 of the mycelia becomes brown. With exposure to open air, mycelia turns reddish brown at the surface and eventually forms a dark brown protective dry surface which functions like a tree bark. The inner substrate becomes soft and moist as a consequence of fungal metabolic activities. Be aware that moist coat invites contamination.
Fruiting induction (Oei 1996)
The following factors promote fruiting:- temperature fluctuation
- high humdity
- water soaking (Royse 1997: 2-4 hr. at 12oC; Stamets 1993:24-48 hr.)
- removal of CO2, or increase of oxygen supply
- physical shocks (agitation, disturbance):
- stab (with a long metal needle) and inject (with water)
- turn the blocks up-side-down
- beating (e.g. natural logs)
Fruiting development
- primordia formation at the tip of the bump (blister)
- formation of the young mushroom button (dark brown)
- elongation of the stipe (stalk) as the button increases in size
- expanding (opening) of the mushroom cap; color becomes lighter
Harvest And Preparation For Second And Subsequent Flushes
Be aware that some fast-growing strains (e.g. China-Stamets-2) may produce unexpected pre-mature fruiting before mycelial maturation (not desirable). Care should be taken to move the blocks as little as possible during spawn run as moving (physical shock) may trigger pre-mature fruiting in such strains. Lower the humidity to 60% R. H. for 6-12 hr. before harvesting.
Harvest when the edge of the mushroom cap is still in-rolled, or when the mushroom cap is only partly extended (60-70%) before it is fully open, as the market dictates. Hand pick the mushroom by holding the mushroom stalk and gently twisyting it from the substrate block. Trim the end of the stalk of the harvest when necessary. Cut off residual stalk stubs from the substrate.
Dry (Stamets 1993: 30-50% R.H. at 21°C, 7-10 days of dormancy), then soak the substrate block for up to 12 hr. for the second flush, and up to 18 hr. for the third flush (Royse 1997). Adjust accordingly. Larger bags with more substrate produce more flushes.