A Practical Guide For Synthetic-Log Cultivation Of Grifola frondosa (Maitake)
Courtesy of Dr. Alice Chen
Commissioned to be written by UNICORN Imp. Mfg. Corp
for reference by clients of Unicorn Imp. & Mfg. Corp.
Bags used are UNICORN Type:- 3T, and 14
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This cultivation manual for Maitake-mushroom production is written in meeting the need for a practical, concrete, and easy to follow guide. Synthetic-log cultivation, a methodology well-tested technically is chosen for growing Grifola frondosa, a prized edible of biomedical importance, using of UNICORN polypropylene bags, manufactured by UNICORN Imp & Mfg. Corp.
Characteristics of this promising mushroom is high lighted for growers to keep in mind, as they proceed to learn how to grow the mushroom. Details are given for the process of cultivation, including selection of strains, types of spawn, where to obtain the spawn, where to obtain bags for mushroom cultivation, and substrate formulation.
Guidelines on how to regulate growth parameters (temperature, relative humidity light and ventilation in terms of CO2vs O2) for each growth stage are constructed in the table form, readily accessibe for application. Practices in China, Japan and North America are given for comparison. Time required for incubation and expected yield are also included. Efforts are made to demonstrate how the maitake mushroom grow by providing vivid sequential images. Selected photos taken during the process of production are used. Land-mark stages of Maitake growth and differentiation are delineated, from spawn run to the formation of mature Maitake fruiting cluster. Emphasis is made on major morphogenetic transitions, such as, mycelial-mat formation, primordia initiation, and fruiting-body development. Clear descriptions of Maitake fruiting clusters at peak, ready for harvest are provided, as well as what to avoid. Information on how to harvest the mushroom can also be found.
Of particular interest is a section on problem solving and helpful notes. It is hoped that these discussions will benefit both the new growers and the more experienced ones who encounter difficulties in the process of growing Maitake.
Growers must be aware that single-minded devotion is required to cultivate Grifola frondosa, a mushroom with intricate structure, larger than usual size, and great appatite for oxygen.
Table of Contents
Table of Contents
List of Tables
List of Figures
Types of Spawn
Sources of Obtaining Spawn
Sources for Cultivation Bags
Management of Growth Parameters
Observation of How Maitake Grow
Fruiting Body Development
The Brain Stage
The Cauliflower Stage
The Cluster Flower Stage
Appendix (Problem Solving and Helpful Notes)
List of Tables
- Supplemented sawdust (fine + coarse)-bran substrate
- Supplemented sawdust (fine + coarse)-bran substrate with the addition of soil
- Supplemented sawdust (fine + coarse)-bran substrate with the addition of spent substrate and soil
Management of Growth Parameters
- Maitake synthetic-log cultivation in China
- Maitake synthetic-log cultivation in Japan
- Maitake synthetic-log cultivation in North America
- Maitake synthetic-log cultivation for home growers
List of Figures
Observation Of Mycelial Growth, Spawn Run, Primordia Initiation And Fruiting-Body Development
- Maitake mycelia, 4 and 10 days after inoculation onto 3% Malt Agar (Paul Stamets, President of Fungi Perfecti, Olympia, WA, USA).
- Spawn run (growth stage), 17 days. White young mycelia penetrate to the surface of the substrate.
- Spawn run (maturation stage), 30 days. Mature mycelia, white, with orange-brown discoloration indicating metabolic activities.
- Spawn run 42 days (primordia initiation in the closed bag). Grayish mounds of primordia are formed on mature mycelia in bags.
- Primordia initiation
- The top of the bags just opened for greater access to light and oxygen.
- 2 days after opening, the primordia became larger.
- Large grayish black primordia, globular, ball-like, offen dotted with exudates.
- The brain stage and further development;
- a. As the dark grayish black primordia develop, convoluted folds appear on the surface, as if a brain.
- b. Further growth.
- Post brain stages.
- Young overlapping fan-shaped pilei (caps) are formed in a cluster.
- Various degree of pileal development in the young Maitake fruiting body.
- The cauliflower stage;
- Progressing to the cauliflower stage.
- Lighter, almost White, the developing cluster has overlapping petals with elongated lateral stems, each with a young cap on the upper portion, as if a cauliflower.
- The cluster flower stage. Mature fruiting cluster with overlapping petals (caps + lateral stems) extending outward, as if a cluster flower. Check features in relation to harvest.
- Maitake fruiting clusters produced in North America by Skunk Bay Mushroom Farm, Hansville, WA, USA (Bob Ames).
- Maitake fruiting clusters produced by synthetic-log production in China – (Prof. Nian Lai Huang, Director, Sanming Mycological Research – Institute, Sanming City, Fujian Province, China).
Cultivation of maitake mushroom with soil casing
- Maitake cultivation with soil casing.
- Maitake mycelia began to aggregate on soil surface, in preparation for primordia initiation.
- A portrait of a vigorous young Maitake cluster, thriving in the growth environment with soil casing.
- The cauliflower stage, successfully cultivated with soil casing
(a + b). The developing Maitake fruiting cluster has overlapping petals with elongated lateral stems, each with a young pileus (cap) on the upper portion, as if a cauliflower.
- Prolific production of
- Maitake cluster flowers, cultivated with soil casing, and
- a close examination.
It takes undivided attention to grow Maitake. Most helpful is to grasp the characteristics of this highly aerobic mushroom of enomorous size in nature, with short, chunky, highly-branched stems, and numerous overlapping caps formed in a cluster. The fact that Maitake grows in temperate climates and forms fruiting bodies in the Fall, defines the temperature requirement for cultivation (Chen et al., 1998a, b,c).
Study the specific requirement of each growth stage, particularly the major morphogenetic transitions (Moore and Chiu., 1998), such as formation of mycelial mat on the substrate surface, initiation of primordia and differentiation of the fruiting body. After intellectually and thoroughly understanding the process, it is essential to implement your carefully laid-out plan, using a good practical guide as a reference.
It is wise not to share the same growing room of Maitake with other mushrooms, since greater attention to detail is required, compared to growing other species. Once you learn how to cultivate this choice edible with promising medicinal properties (Nanba, 1995, 1997; Stamets, 1993, 1998), you will find it a most rewarding experience.
Strain selection in Maitake is crucial before plumging into production. Unlike Oyster mushrooms (Pleurotus spp.) or Reishi mushrooms (Ganoderma spp.), a high percentage of Grifola frondosa strains, whether isolated from natural habitats or obtained from culture collections, do not fruit well, if at all (Huang, 1997; Stamets, 1993). There are also considerable differences among strains in growth rate, yield, temperature requirements, and features of the fruiting body, such as color,and shape of the caps. Testing a new strain before production is therefore essential. Fig. 1. shows the mycelial colonies on agar plates from a North American strain of Grifola frondosa cloned from the wild in Pennsylvania, USA. Strains in mushrooms are similar to races in human beings. Different human races, sharing a common genetic heritage, belong to a single species, Homo sapiens. A mushroom species may also consist of many strains, each with a distinct gentotype (genetic make-up) and phenotype (observable features), but are compatible in mating. Reputable mushroom growers often take pride in developing their own unique high quality strains.
Types of Spawn
Spawn, the (asexual) mushroom seed, is the vigorous mycelial growth of, usually a single fungus on a chosen substrate-material (liquid media, grains, sawdust substrates, and wooden sticks, etc.). For growing mushrooms, this living pure culture, the vegetative propagation stage of a fungus, is used to inoculate, under sterile conditions, new substrates in such containers as specially designed polyethylene bags with microfilter windows for breathing.
You can obtain from well-established mushroom growers ready-to-fruit blocks already inoculated with your favorite mushroom species, the so called colonized synthetic logs. With some training on aseptic techniques, you can start with spawn to inoculate synthetic logs yourself for mushroom production. Following are types of spawn commonly used by mushroom growers including Maitake growers:
1. Liquid spawn
Liquid spawn can be labor-saving in spawning (inoculation) through the use of a specially-designed inocular. Liquid-surface still culture and submerged fermentation have been used to produce liquid spawn. Production of spawn by submerged fermentation can be made on an industrial scale (Fang et al., 1998), a step leading mushroom cultivation into a new century.
2. Grain spawn – A variety of grains, such as millet, rye, wheat, sorghum and milo can be used (Chalmer, 1994; Stamets, 1993).
3. Sawdust spawn Supplemented sawdust-bran substrates are usually the choice.
4. Wooden stick (skewer) spawn . This type of spawn can be easy to manipulate (Oei, 1996).
Sources Of Obtaining Spawn
world-wide web site: http://www.fungi.com
P. O. Box 7634-MGN
Olympia, WA 98507, USA
Field and Forest Products
N 3296 Kozuzek
Peshtigo, WI 54157, USA
world-wide web site: thefarm.org/mushroom
Summertown, TN 38483, USA
R. R. #1
Wiarton, Ont. Canada NOH2TO
P. O. Box 283
Aldergrove, B.C., Canada, V4W 2T8
Sources For Cultivation Bags
Unicorn Imp. & Mfg. Corp.
1918 Platinum St
Garland, TX 75042
world wide web site: www.unicornbags.com
Based on the highly aerobic nature and larger than usual size, Maitake requires a lot of oxygen to grow. A mixture of hardwood sawdust, fine plus coarse, (Huang, 1997), or a mixture of hardwood sawdust and wood chips (Stamets, 1993), therefore, is commonly used as the basal ingredient in the substrate to provide good air exchange. Make sure that the coarser sawdust or wood chips does not puncture the bag. There is no need to age any component of the substrate for growing Maitake. Sawdust from aged logs, on the other hand, has been used successfully for Maitake production as long as proper sterilization is observed.
For the cultivation of Grifola frondosa, the basal ingredient in the substrate, hardwood sawdust (fine plus coarse) is usually 75-80%. The basal ingredient can be substituted, in part, by cotton-seed hulls (25%) or spent substrate (20%). Recycling of the spent substrate is an environmentally sound practice. The basal ingredient is usually supplemented with wheat bran (coarse), lime, sucrose, and sometimes soil. Wheat bran, a source of thiamine (vitamin B1), is essential for fruiting-body formation, while calcium contributes to differentiation of the basidiocarps (fruiting-bodies in basidiomycetes). Humus-rich surface soil from broad-leaf forest has been found to enhance the growth of Maitake mushrooms. Following are formulas of Maitake substrates, adopted primarily from (Wu et al., in Huang, ed., 1997). For further information, see Chalmer (1994), Chiu et al. (1998); Huang (1987, 1993, 1997), Kirchhoff (1996), Lee (1994, 1996), Royse and Gardino (1997), and Stamets (1993).
I. hardwood sawdust (fine + coarse), 3:1 75%
Calcium compound 1%
lime (CaCO3. 6H2O) or
H2O (moisture content) 60-63%
II. hardwood sawdust (fine + coarse), 3:1 80%
lime (CaCO3.6H2O) 1%
soil, hardwood forest (surface), dry wt. 15% (of the above mixture)
H2O (moisture content) 60-63%
III. hardwood sawdust, fine 40%, coarse 20%
wheat bran (coarse) or substitute 10 % soil,
hardwood forest (surface), dry wt. 10%
Management Of Growth Parameters
Several management schemes are given here as references. Make special note on the set of growth-parameter requirements for each mushroom stage. Close attention should be given to regulate temperature, relative humidity, light and air (in terms of O2 vs CO2, adjusted by air exchange in ventilation). For instance, the temperature for fruiting-body development is lower than that of spawn run and sometimes primordia initiation (strain specific), the intensity of light is higher, and the relative humidity of the air is usually also high. Fluctuation of the temperature should be minimized to avoid condensation.
In China and Japan, spawn run (+ primordia initiation) and fruiting-body development are carried out in two different rooms. Primordia are initially formed in the enclosed bag, while the fruiting body in the bag with the top open. After the growing synthetic logs are adjusted to the new fruiting environment for 2-3 days, the cotton plugs are removed or slits made in bags above the substrate for greater access to oxygen. Some growers punch holes on the bottom of the bag for drainage.
In evaluating the following management schemes, take into consideration that there may be differences in strains (growth rate, yield, temperature), substrates (composition and size), bags (design, size, and features of microfilter), spawn (quality, size and distribution), how the synthetic logs are arranged, as well as whether soil casing is used. Soil casing has been reported to produce higher yield. Treated soil from humus-rich hardwood forest, garden or rice paddy (soil particle, 0.5-0.8 cm in diameter) is used. Sandy soil or clay has not been found as beneficial (Wu et al., 1997).
I. Maitake synthetic-log cultivation in China. (This may not be applicable in the United States)
Optimum Range (in enclosed bags)
|60-70||ambient air 80-90||90-95|
through out spawn run
(300 during the day)
|CO2 mycelia can tolerate High O2 = fresh air Ventilation higher CO2 level
open the top of the bag after 2-3 days
ventilate 5-6 times/ day ventilate 5-6 times/day
|pH 5.5-6.5 initially|
(no soil casing)
10-15 surface above soil
15-18 to mature fruiting
|Ref. Wu, J. L., et al., in Huang (ed.), 1997
mushroom production: ca. 3 months or longer.
Yield = 150-300 g /bag, 300-500 g/bag with soil casing.
1/3-2/3 lb/bag, 2/3-ca. 1lb/bag
Strains isolated from high altitude in subtropical Fujian province in Southern China
II. Maitake synthetic-log cultivation in Japan.
|Parameter||Spawn Run||Primordia Initiation||Fruiting-body development|
|stage I||II||(in enclosed bags*)||(in cut-opened bags)|
+ 2 or 3
= ca. 24-25
23 best for
|same as spawn run||85-95|
|< 0.3% (3000 ppm)
bags 3-4 cm apart
|0.1% (1000 ppm)
> 0.15% (1500 ppm)
results in small/thin caps
after 2-3 days cut bag
(x on top) for ventilation
|Reference Huang, 1997: 1994 Annual report of mushroom in Japan, p. 167-172.
mushroom production: ca. 3+1/2 months.
* heat sealed bags with microfilters for breathing used.
III. Maitake synthetic-log cultivation in North America.
(in enclosed bags*)
(in enclosed bags*)
stems fruiting bodies
(in opened bags)
|Reference Stamets, 1993, p. 375
mushroom production: ca. 3+1/2 months
* heat-sealed bags with microfilters for breathing used
** Royse and Guardino, 1997 lower temperature, higher light (upper limit) used for primordia initiation, and fruiting, vs the practice in China.
North American strains (PENN, re. Canada)
IV. Maitake synthetic-log cultivation for home growers.
(in enclosed bags)
(in enclosed bags)
|Fruiting body Development
(in tented opened bags)
% within sealed bags
within sealed bags at 60-70% ambient R.H.
within tented blocks*
|Light||N/A||intermittent||same as shade (3/10 sunlight)|
|Ventilation||open bag for increased air not specific when primordia reach 1-2″ in diameter in enclosed bag|
|4-5||4-6||3 wk growth maturation|
|Reference Chalmer, 1994
mushroom production: 3+1/2 months.
* Tented block: when ambient R.H < 75%, place a clear synthetic bag over top of the substrate block to maintain relative humidity.
Observation Of How Maitake Mushrooms Grow
(spawn run + primordia initiation + fruiting-body development)
Growth ( + differentiation) is a continuous process. Each stage merges with the other. Overlapping descriptions are sometimes given.
Spawn Run (growth + maturation)
This is the vegetative mycelial phase leading to primordia initiation (also included).- undifferentiated white mycelia – white mycelia with orange brown discoloration.- mycelial mat on substrate surface – uneven topography on mycelial surface
As illustrated by figures:- In 9 days, undifferentiated white mycelia begin to colonize the substrate.- By 2 + 1/2 weeks (17 days), white young mycelia penetrate thoughout the surface of the substrate in the sealed bags (Fig. 2).- After a month or so (30 days), orange brown exudates indicating metabolic activities are observed to cause discoloration of the white mycelia (Fig. 3).- At the surface of the substrate, tighter mycelial growth gives rise to a surface mycelial mat toward later stage of the spawn run. – The topography of the mycelial surface becomes uneven with grayish amorphous mass. – By 40 days or so (42 days), grayish primordia reaching 1-2″ in diameter are formed on the substrate surface in the closed bag (Fig. 4). Transfer these bags to a facility set up for fruiting-body development. After 2-3 days, open the top of the bags.
Grifola frondosa has a prolonged spawn run, when the substrate is colonized by the spawn. Although mycelia can grow in the absence of light, a low level of light (50 lux) throughout the period of Maitake spawn run has been found to facilitate primordia initiation (Wu et al., 1997). In spawn run, a growth period is followed by a maturation period of metabolic activities leading to primordia initiation at increased light (200 lux), ample oxygen and high humidity within the sealed bag.
Dark gray amorphous mass on mycelial surface developed in sealed bags with ventilation.- dark grayish black mounds develop into globular, ball-like, primordia, dotted with exudates, sometimes light yellow (Fig. 5, 6). Do not wipe off the exudates.- development of primordia leading to formation of fruiting-bodies.
Fruiting Body Development
(primordia stage, brain stage, cauliflower stage and cluster flower stage
Several distinct morphological stages as above can be observed in typical Maitake strains (Figs. 5-10). Figs. 11 and 12 Maitake clusters produced by synthetic logs without soil casing. Figs. 14-16 show Maitake cultivation with soil casing. All the mushrooms were produced by the successful management of growth parameters, specific for each developmental stages.
THE BRAIN STAGE. As the dark grayish black primordia grow, convoluted folds appear on the surface, as if a brain (Fig. 7).
THE CAULIFLOWER STAGE. Further growth includes unfolding of the convoluted folds on the surface of the dark primordia into overlapping young pilei (caps) formed in a cluster. This is followed by elongation of the lateral stems, each with a young pileus (cap) on the upper portion. The stems are highly and repeatedly branched, sharing a short and chunky base. This stage is a “cauliflower” look alike (Fig. 9), when the color of the fruiting body becomes lighter to almost white.
THE CLUSTER FLOWER STAGE. As the mushroom continues to grow, overlapping fan-shaped caps in a cluster are developed along the elongated stems, creating the cluster flower stage (Fig. 10). The color of the mushroom becomes progressively lighter during the intricate morphogenesis from the dark grayish-black primordia. Depending on strains, Maitake mushrooms are light gray, grayish white or light brownish yellow, etc.
TIMELY HARVEST. Fig. 10 shows Maitake mushrooms fully formed, as if cluster flowers. Fig. 11 and 12 are Maitake fruiting clusters produced by synthetic logs in China and North America. Watch for timely harvest, when:
- the mushroom cluster has been fully formed and increases in size (Fig. 10). The fan-shaped or semi-circular, irregularly-shaped petals (caps + lateral stems) extend outward like a cluster flower in bloom, reaching 80% in unfolding. The petals are growing longer and thicker with thinner pileal (of caps) margins curling slightly inward.color of the fruiting body changes from dark gray brown when young to lighter gray, grayish white, or light yellowish brown.
- pilei (caps) no longer have whitish or grayish-white margin of undifferentiated new growth in a band or spots.
- at the onset of differentiation of hymenial tubes (fertile tubes where basidiospores are formed), minute pores (end of hymenial tubes) appear on the back, the underside of the petals (caps + lateral stems), but no pores at the margin of the caps, 1 cm from the edge. There are also no pores at the base of the cluster stem.- the mushroom cluster gives off a clearly detectable pleasant mushroom aroma.- Harvest before petals droop or curve downward.
- Harvest before the white basidiospores are released.If the ripe fruiting cluster is left unattended, the fruitng body may become softened, giving off foul fishy smell.
Stop misting with water a day before harvest to prevent bacteria intrusion. Proceed with caution to harvest these large but fragile Maitake fruiting bodies. With one hand holding the base and supporting the weight of the big cluster, cut off the thick base with a small sharp knife with the other hand. Rotate the cluster gently and pull upward carefully if necessary, such as when soil casing is used for cultivation. Cut off the chunky base and trim if necessary to remove debris. Stamets (1993) wrap the harvested mushrooms in rice paper, then store them at 35°F (1-2°C) in refrigeration, giving an expected shelf life of 2 weeks. Maitake fruiting efficiency (yield) is generally low ( 0.5 -1 lb or 2 lbs/ bag). Virtually all sold at fresh market.
This practical guide for growing Maitke is dedicated to all who love to grow specialty mushrooms and those who enjoy eating.
The author is most grateful for the generous contribution of photos from supporting colleagues, , including, Paul Stamets, Bob Ames, Messrs, Nian Lai Huang, Jing Lun Wu and Sheng Hua Han. Dr. Philip G. Miles, , and Mrs. Eleanor Miles, concrete guidelines for writing such a practical cultivation guide for Grifola frondosa, from Mr. Lou Hsu, Director of Unicorn, Imp. & Mfg. Corp., Commerce, TX, USA, made this work possible.
Gratitude to Mr. William G. Rand, and his wife, Joan, for editing the paper.
Chalmers, Williams, 1994. Cultivation of the Maitake mushroom. Mushroom world, June, 1994.
Chen, Alice W. , Paul Stamets, Robert B.Cooper, Nia Lai Huang and Sheng Hua Han, 1998 a, b. Grifora frondosa (Maitake): Ecology and Morpholog , Mushroom Growers’ Newsletter, Mar. and June, 1998.
Chen, Alice W., Paul Stamets, Robert B. Cooper, Nian Lai Huang and Sheng Hua Han, 1998c. Grifola frondosa (Maitake): ecology and morphogenesis. Nanjing, China: Science and Cultivation of Mushrooms.
Chiu, G. P. , P. L. Sun and S. H. Chong, 1998. High-yield cultivation of Grifola frondosa and nutritional analysis. Journal of Eidible Fungi of China, Mar. 1998, 17(3):31-33 (in Chinese).
Fang, Ke Wu and J. H. Zhu, 1998. Application of liquid spawn in edible fungi production. Mushroom Biology and Mushroom Products, Nanjing, China, pp. 36- 38.
Huang, Nian-Lai, 1987. Grifola frondosa, in Huang, N. L. (ed.): Edible Fungi. Nanjing, China: Nanjing University Press, pp. 677-681 (in Chinese).
Huang, Nian Lai, 1993. The Cultivation of Grifola frondosa, in Huang, N. L. (ed.): The Encyclopedia of Chinese Edible Fungi. Beijing, China:The Agricultural Press, pp. 275-276 (in Chinese).
Huang, Nian Lai, 1997. Japanese Grifola frondosa, in Huang, N. L. (ed.): Cultivation of Eighteen Precious and Delicious Eidible Fungi. Beijing, China: Chinese Agricural Press, pp. 145-153 (in Chinese).
Kirchhoff, Burkhard, 1996. Investigations of genotypes and substrates for the fruiting body production of Grifola frondosa (Dick. : Fr.). Royse, Daneil J. (ed.): Mushroom Biology and Mushroom Products. State College, PA: PENN State University Press, pp. 432-441.
Lee, E., 1994. Production of Shiitake, Oyster and Maitake in Connecticut. Mushroom News, Mar. 1994, 11-14.
Lee, E., 1996. Production of Shiitake and Maitake Mushrooms in Connecticut. Mushroom News, 44(2), 6-11.
Moore, David and S. W. Chiu, 1998. Genetic components of fruit body morphogenesis. Lu, Maolin, G. Kai, H. F. Si and M. J. Chen (ed.): Science and Cultivation of Mushrooms, Nanjing, China, pp. 85-99.
Nanba, H. , 1995. Activity of Maitake D-fraction to inhibit carcinogenesis and metastasis. Annals of the New York Academy of Sciences, 768: 243-245.
Nanba, H. 1997. Maitake D-fraction: Healing and preventive potential for cancer. Journal of Orthomolecular Medicine, 12, 43-49.
Oei, Peter, 1996. Mushroom Cultivation, with Special Emphais on Appropriate Techniques for Developing Countries. Leiden, The Netherlands: Tool Publications.
Royse, Daniel J. and J. Guardino, 1997. Specialty mushrooms: Enokitake and Maitake. 45 (2), 28-31.
Stamets, Paul, 1993. Growing gourmet and medicinal mushrooms. Berkeley, CA: Ten Speed Press.
Stamets, Paul, 1998. Mycomedicinals, an informational booklet on medicinal mushrooms. Olympia, WA: MycoMedia.
Wu, Jing lun, G. Z. Lin, M. Z. Fu and Z. C. Wei, 1997. Grifola frondosa. Huang, N. L. (ed.): Cultivation of Eighteen Precious and Delicious Chinese Edible Fungi. Beijing, China: Chinese Agricultural Press, pp. 130-145 (in Chinese).
APPENDIX Maitake Synthetic-log Cultivation Problem-solving and Helpful Notes
Selecting high-yield, fast-growing, vigorous fruiting strains
Strains with a spawn run of 30 days before primordia initiation are considered fast. Many require 60 -90 days or more of mycelial growth and maturation. Make sure the strain you obtain has been tested and shown to be a good fruiting strain. Ninety percent of some tested strains from culture collections and wild isolates by a reputable grower do not fruit well, if at all.
Substrate plant species
Variation in production among strains on substrates of different plant species can be considerable. In North America, oak is the most-commonly used species for substrate. Numerous hardwood species, such as maple, elm, beech, alder, blackgum, larch, poplar, cottonwood, and willow can also be used, depending on the availability and cost-effectiveness.
Good aeration in the substrate Good air exchange in the substrate should be provided for this highly aerobic mushroom of considerable size. A mixture of hardwood sawdust (fine + coarse) 3:1 is recommended. Use large-bore cultivation bags with microfilters for breathing. Do not fill the cultivation bag to the rim with the substrate. Leave ample air space above the substrate for a good supply of oxygen as well as air exchange.
Ways to shorten spawn run
- Select a vigorous fast-growing fruiting strain.
- Use the highest optimal temperature to grow mycelia during spawn run.
- Use a generous amount of spawn (inoculum) of the best quality you can find. Use through-spawning by distributing the spawn throughout the substrate. Rate of spawn to substrate, 1:10 or 1 : 20 is generally adopted. A North American grower demonstrated that when millet-based spawn is increased from a few grams to 500 g/7 lb substrate, the spawn run could be shortened to merely a week or so. Check what is cost-affective.
- Use bags with large bore (not narrow and long). Leave ample air space above the substrate for oxygen and air exchange. When using wide bags, caution should be taken to avoid air contamination during spawning (inoculation).
- Use a good substrate formula with effective aeration: a. Use a mixture of hardwood sawdust (fine + coarse), 3:1 b. Add the right amount of water for moisture content.
Light or no light for spawn run
Since the level of light used and the length of the spawn run have a direct impact on formation of the surface mycelial mat, and in turn, primordia initiation, you may find it easier to use a low level of light (50 lux or lower) throughtout the spawn run (growth period + maturation period).
Surface mycelial mat
Surface mycelial mat should not be grayish brown or too thick. Proper level of light as well as the right length of the spawn run is essential in forming a good surface mycelial mat, condusive to primordia initiation.
Failure of primordia initiation
Double check if your strain has the right genotype (genetic make up), capable of producing well-formed fruiting bodies. There is no need of cold shock to initiate Maitake primordia.
Can sometimes be traced back to the spawn run in relation to light. Too much light during the early and mid stage of the spawn run produce a grayish-brown mat which is most undesirable for the initiation of light-induced and highly pigmented primordia. On the other hand, prolonged spawn run in the absence of light may lead to increase in the thickness of the surface mycelial mat. Overly thick mycelial mat on the surface of the substrate may delay or prevent the formation of primordia.
Primordia initiation is best if it takes place in one or two sites on the surface mycelial mat. Avoid overcrowding of numerous minute primordia all over the surface. Survival of these small primordia is questionable.
Timing for bag-opening vital for primordia survival
When primordia reach 1-2″(2.54-5.08 cm) in diameter with a certain degree of maturity, open the top of the bag timely, or cut splits in bags for increased oxygen and air exchange. Open the bag too early, the fragile primordia will not survive the change to fruiting environment with a new set of growth parameters. Open too late, the primordia will be arrested from further differentiation and development.
Narrow range of fruiting temperature
Keep in mind that Griforla frondosa is a mushroom of temperate climates. Maitake fruiting temperature:
8-15°C (Chalmer, 1994)
10 -15.6°C (18°C) (Stamets, 1993)
16-18°C (Huang, 1997)
15-20°C (Wu et al., 1997)
Find out the optimal fruiting temperature of your strain. Substanial fluctuation of temperature beyond the optimal range arrests fruitng-body differentiation and development. Note that the Japanese keeps strict temperature control of Maitake fruiting, allowing only 2oC in difference (16-18oC). By minimizing the fluctuation of temperature, chances of having water condensation can be reduced.
Be aware that the substrate temperature can be 2-3oC higher than the ambient air temperature set for Maitake production. Respiration of massive fungal biomass can generate a considerable amount of heat as well as moisture.
Retain substrate moisture for fruiting-body development
In the transition from primordia initiation to fruiting-body development, do not remove the entire bag from the colonized synthetic log. Open the top of the bag only to retain substrate moisture. Do not open the bags immediately after being transferred to a new fruiting environment. Wait for 2-3 days to adjust to the new fruiting parameters before opening. Development of Maitake mushrooms of considerable size requires a lot of water. Provide high relative humidity also but avoid water condensation. Direct contact of water on fruiting bodies invites bacteria as inhabitants on these chunky and intricate mushrooms.
No direct sunlight for growing Maitake
Light control (200-500 lux) or shading (sunlight to shade, 3 :7) is necessary. Each growth stage has its own requirement.
Fruiting efficiency (yield) in Maitake is general low. Yield can be improved by using a larger amount of substrate, for instance, using 7 lb vs 5 lb. Soil casing has been reported to increase yield. Soil casing can also be appied to individual bags.
A second flush can be generated by embedding the spent substrate after harvest in sawdust, and then covering with soil. A record Maitake fruiting body of 10 lb has been obtained by cultivation with soil casing. Soil casing can also be applied to unsuccessful fruiting blocks.
Fruiting-body success rate
SUCCESSFUL MANAGEMENT OF GROWTH PARAMETERS IS A PRIORITY
Control the delicate balance between ventilation vs relative humidity. Ventilation increases air exchange in bringing fresh oxygen. However, in the process of ventilation, air moisture (relative humidty) can be disrupted. Ventilate more times but shorter periods.
Observe the optimal relative humidity for fruiting (85 or 90 % to 95%). Relative humidity below 80% may lead to FB death (death of fruiting bodies) from drought. Young fruiting bodies are especially vulnerable to drought. On the other hand, relative humidity near 100%, may lead to rot.
(200-500 lux) during fruiting increases FB success rate. Less than adquate light, affects fruiting-body differentiation and pigment formation and gives rise to malformed pilei (caps), abnormal fruiting clusters, and subnormal fruiting color (very light to white).
Based on the highly aerobic nature of Maitake, high oxygen level should be maintained for fruiting. Low O2 and high CO2 give rise to antler-form fruiting bodies. Extreme O2deficiency arrests fruiting-body development and leads to decay.
(Inputs from listed references have taken into consideration)
COPYRIGHT: Alice W. Chen, Ph.D. © 1998
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