Group Title: Bul
Title: Growing shiitake mushrooms (Lentinus edodes) in Florida
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Title: Growing shiitake mushrooms (Lentinus edodes) in Florida
Series Title: Bul
Physical Description: 7 p. : ill. ; 28 cm.
Language: English
Creator: Webb, Roger S ( Roger Stuart ), 1950-
Floorida Cooperative Extension Service
Publisher: University of Florida, Cooperative Extension Service, Institute of Food and Agricultural Sciences
Place of Publication: Gainesville Fla
Publication Date: 1995
Subject: Shiitake -- Florida   ( lcsh )
Mushroom culture -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (p. 6-7).
Statement of Responsibility: R.S. Webb ... et al..
General Note: Cover title.
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Bibliographic ID: UF00008537
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA6799
ltuf - AKU6414
oclc - 35291870
alephbibnum - 002106985

Full Text
Bul 255

Growing Shiitake Mushrooms
(Lentinus edodes) in Florida
R.S. Webb, J.W. Kimbrough, C. Olson, and J.C. Edwards

Cooperative Extension Service
Institute of Food and Agricultural Sciences

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no. 255

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Cooperative Extension Service
Institute of Food and Agricultural Sciences

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Growing Shiitake Mushrooms (Lentinus edodes) in Florida1

R.S. Webb, J.W. Kimbrough, C. Olson and J.C. Edwards2

Shiitake (she-tah-key) is the major edible mushroom
grown throughout Asia. In the United States, shiitake
mushrooms are becoming a familiar sight in oriental
food stores and restaurants, and in the exotic food
sections of many supermarkets. More and more
restaurants are now serving shiitake and other exotic
mushroom dishes. The United States was, in 1978, the
third largest importer of dried shiitake mushrooms from
Japan with wholesale purchases totaling $6 million.
With the majority of mushrooms sold in oriental food
stores and restaurants, a virtually untapped domestic
market exists for producers in the United States.

The purpose of this bulletin is to explain procedures used
for growing shiitake mushrooms, resources and
equipment needed, suppliers of spawn and supplies,
potential problems, and marketing information to
potential Florida growers.


The mushroom, Lentinus edodes (Berk.) Singer, is a
wood-rotting fungus that grows on a wide variety of
hardwood tree species. Lentinus is one of a large
number of genera belonging to the mushroom family
Tricholomataceae and according to Singer (1986), there
are fourteen species of Lentinus recognized worldwide.
Several species of Lentinus have considerable economic
value. Shiitake is a billion dollar industry in Asia, and
in addition to its culinary uses, L. edodes is of medical
interest as it contains the antibiotic "cortinellin" and

other antiviral compounds and is also believed to lower
plasma cholesterol in animals due to eritodenine (Singer,
1986). Other species in the genus Lentinus are of
negative economic importance: these are wood-rotting
fungi that commonly digest railroad ties, bridges, and
wooden houses.

Shiitake gets its common name from its most abundant
hardwood host, species of the genus Pasania, the "shii"
tree. Pasania is a genus of the oak family with more
than 100 species found in eastern Asia. Thus, shiitake
comes from "shii" for the host tree and "take", which
means mushroom in Japanese.

Cultivation and export from Japan

According to Leatham (1982), shiitake cultivation began
in Japan centuries ago when farmers would search the
forest for shii logs bearing L. edodes mushrooms. They
learned to manage log inoculation by stacking
mushroom-bearing logs with freshly-cut logs. Shiitake
mushrooms became widely prized because of their flavor
and were used extensively in folk medicine.

Successful large-scale cultivation of shiitake began in the
1940s in Japan with the development of new techniques
for inoculation, and by 1978 the industry had surpassed
$1.1 billion. Currently, 92% of the world supply of
shiitake is produced in Japan and it is the most valuable
agricultural export commodity of that country.

1. This document is Bulletin 255, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published
August 1989. Reviewed June 1995.
2. R.S. Webb, former associate professor, School of Forest Resources and Conservation; J.W. Kimbrough, professor, Plant Pathology department; C.B.
Olson, extension director, Taylor County Cooperative Extension Service; Institute of Food and Agricultural Sciences, University of Florida, Gainesville
FL 32611. J.C. Edwards, extension rural development specialist, Florida A&M University, Tallahassee.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap,
or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.
Florida Cooperative Extension Service/Institute of Food and Agricultural Sciences/University of Florida/ Christine Taylor Stephens, Director


Bulletin 255

Growing Shiitake Mushrooms (Lentinus edodes) in Florida

with Shiitake Mushroom Sauce

Serves 4
Working (and total) time: about 35 minutes

one 1-lb grouper fillet (or monkfish or red snapper)
1/2 oz dried shiitake mushrooms, soaked in
3/4 cup very hot water for 20 minutes
1/4 cup dry sherry
2 tbsp. low-sodium soy sauce
2 tbsp. fresh lime Juice
1 tsp. sugar
1 1/2 tbsp. cornstarch
2 tbsp. safflower oil
2 scallions, trimmed and thinly sliced
1 tbsp. julenned fresh ginger
2 garlic cloves, thinly sliced
1/2 tsp. freshly ground black pepper

Remove the mushrooms from their soaking liquid
and slice them into thin pieces. Set the mushrooms

Pour 1/4 cup of the soaking liquid into a mixing bowl,
being careful to leave any grit from the mushrooms
behind. Stir in the sherry, soy sauce, 1 tbsp of the
lime juice and the sugar. Set the mixture aside.

Rinse the fillet under cold running water and pat it dry
with paper towels. Rub the fillet with the remaining
tbsp of the lime juice, then rub the cornstarch evenly
over both sides of the fish.

Heat the oil in a large, heavy-bottomed skillet
(preferably nonstick) over high heat. When the oil Is
hot, add the fish and sear it on one side for two
minutes. Carefully turn the fillet over; sear it on the
second side for two minutes. Transfer the fish to a

Add the mushrooms, scallions, ginger, garlic and
pepper to the hot skillet. Cook the mixture on high for
one minute, then reduce the heat to low. Pour In the
sherry mixture, replace the fillet, and cover the skillet.
Steam the fish until it is opaque-about five minutes.
Transfer the fish to a warmed serving dish.

Shiitake in the United States

Until 1972, the only shiitake mushrooms available in the
United States were dried specimens, since the
importation of living L. edodes cultures was prohibited
by the U.S. Department of Agriculture. The living
shiitake fungus was quarantined due to a confusion with
a related fungus, L. lepideus, which was associated with
decay of railroad ties. With the removal of the
importation ban and the increase in production-orientated
literature, a dramatic increase in commercial production
of shiitake mushrooms has occurred (although there had

been scattered amateur interest in exotic mushrooms for
years). The field of specialty mushroom-growing is
greatly expanding and gourmet mushrooms are becoming
profitable ventures, with a number of cooperative
growers' organizations forming throughout the country.

The hardwood logs necessary for shiitake production are
a key factor in mushroom production. In Japan--where
land and forests are limited, and in Asia-where
deforestation is increasing at an alarming rate, the future
of traditional production methods is uncertain. However,
in the United States and in Florida, particularly, there are
ample stocks of oaks and other suitable hardwood
species for use in shiitake production.

In Florida, low-quality, under-utilized hardwoods suitable
for shiitake culture cover millions of acres and are
virtually an unlimited source of substrate for mushroom
production. With our ever-growing population, Florida
is a major market for agricultural products and the
potential is significant for an increased shiitake market
share, especially by local producers who may take
advantage of increased Japanese currency values.

Development of a successful, large-scale industry in the
United States will depend on the availability of reliable
spawn as well as the adaptation of production technology
to local conditions. There are a number of spawn
producers and most of the components for a profitable
shiitake industry are present: basic research at a number
of major institutions, production equipment suppliers,
growing consumer interest, periodicals, and conferences.


Successful shiitake production is not difficult but six key
steps in cultivation must be carefully conducted to ensure
an acceptable crop:

1. Production or acquisition of living shiitake
inoculum and proper storage until use;

2. Proper selection, cutting, and handling of
acceptable hardwood host logs;

3. Inoculating logs with shiitake spawn;

4. "Laying" the logs to favor fungal development;

5. Caring for the logs to maintain moisture content
and reduce contamination;

6. Harvesting and storing the mushroom crop.

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Growing Shiitake Mushrooms (Lentinus edodes) in Florida

Potential problems for Florida producers

There are still a number of questions regarding the
potential for growing shiitake mushrooms in Florida that
need to be answered:

* We have little or no information as to whether
hardwood species in Florida will serve as suitable
substrates for this particular fungus.

There are numerous strains of shiitake "spawn" or
inoculum available and which of these is best for
Florida's climate and hardwood species is unknown.

How our climatic conditions affect the growth of
shiitake and whether or not insects or "weed
fungi" will interfere with mushroom production
remains to be investigated.

Mushrooms that degrade wood fall into two general
categories: white rot and brown rot species. Shiitake
is a white rot fungus and may degrade lignin, while
brown rot fungi effectively degrade cellulose. There
are numerous indigenous white and brown rot fungi
that could be extremely detrimental to shiitake
production because they may actively invade and
degrade the substrate.


Actively growing fungal cultures intended for use in
mushroom cultivation are called "spawn". High-quality
spawn may be obtained from a variety of reputable
firms. Prior to ordering, it is a good idea to contact
prospective suppliers to inquire about which spawn types
or strains of shiitake might perform best in the Florida
climate. Some of these suppliers are listed at the end of
this publication.

If you are a novice at mushroom growing, purchasing
contaminant-free, viable shiitake inoculum assures you
of high-quality spawn. Much time and money are lost
when poor-quality inoculum is used as the eventual crop
will largely depend on the type and vigor of the shiitake
strain used.


Trees suited for shiitake mushroom cultivation are
usually deciduous hardwoods and in Florida water oak,
southern red oak, laurel oak, and turkey oak are
considered the best hosts. Other species of oaks should
do well and growers in northern areas of the United

States report high levels of shiitake production on
chestnut, hickory, willow, maple, birch, beech, alder and
hornbeam. Logs should be free of internal decay
symptoms and should be cut from living hardwood trees
during the winter, as trees felled during the colder
months appear to retain bark better, aiding in moisture
retention and reducing the likelihood that contaminating
fungi or bacteria will invade the logs. Low temperatures
also may reduce the population of competitive fungi
normally present at other times of the year. Moisture
levels in freshly cut logs are ideal for fungal growth so
logs should be inoculated as soon as possible after
cutting. Logs that have aged more than 15 days after
felling should not be used for shiitake production as they
will have dried to an unacceptably low internal moisture
content. Damaging the bark on the logs should be
avoided as this may increase internal moisture loss and
allow for entry of contaminating microorganisms. Logs
may be of any size but generally 3 1/2 to 4 feet in length
and 4 to 8 inches in diameter are about the maximum
sizes for easily handling.


Inoculation is the placement of living fungal inoculum
into the sapwood of the log. Shiitake spawn comes in
two forms, 1) sawdust and 2) wooden plugs or dowels
that have been colonized by the shiitake fungus. High-
quality spawn is characterized by a brownish-white,
fuzzy appearance and should not smell mildewy or
moldy which would indicate that the spawn is to old or
contaminated. Spawn should be kept away from direct
sunlight and extremes of temperature and once a
container of spawn is opened, the entire contents must be
used to prevent subsequent contamination. Spawn stored
in a refrigerator may remain viable for several months
but must never be frozen.

During log inoculation, spawn is placed into half-inch
diameter holes 3/4 to 1 1/4 inches deep and then sealed
with a styrofoam plug or wax to retain moisture. Wax
is used as a sealant in Japan in areas with low relative
humidity for maximum conservation of log moisture. A
typical log (5 inches in diameter and 4 feet long) may
have 30 to 40 holes (inoculation sites), spaced
longitudinally and radially over the log (Figure 1).
Inoculate in a shaded area to avoid direct exposure of
spawn to ultraviolet light.

Page 3

Growing Shiitake Mushrooms (Lentinus edodes) in Florida

figure i. inoculation sues can oe maae Dy airing.

The spawn "run" or laying the logs

After inoculation, logs may be stacked in parallel layers
("ricks") or inclined against a railing for the spawn run
or development (Figure 2). In Florida, a heavily-shaded
area (at least 75% shade) exposed to rain and good air
movement is best since these conditions protect the logs
from direct sun and help reduce the likelihood of
contaminating fungi. The heat of direct sunlight can kill
the shiitake fungus during hot weather. Optimal
conditions for the fungus to successfully colonize and
become established in logs are 600-800F and 80-85%
relative humidity.

I-gure z. Inoculatea logs are leaned age
stacked in ricks.

Caring for the logs

The area where the logs are laid should have a
convenient water source, since logs should be wetted in
dry times during the spawn run. Wetting should
generally not be done more than once or twice a month
with a sprinkling of 2 to 8 hours duration.
Approximately 70% moisture content is optimum for
fungal growth. This may be monitored by periodically

checking the log moisture level (see the next section:
monitoring log moisture content). Some strains of
shiitake may colonize inoculated logs in 4 to 6 months
while other strains take 18 months or longer. Complete
colonization must take place before fruiting will occur.
Check the progress of colonization several months after
inoculation by removing a styrofoam plug from the
inoculation site and inspecting for a whitish fungal
growth in the inoculation hole, If wax rather than
styrofoam plugs was used to seal the holes, then a small
piece of bark near the inoculation site may be removed
to see if the mycelium is colonizing the wood. If the
wood appears dark or of a color other than whitish, then
the shiitake inoculum did not successfully colonize the
inoculation site, most likely due to competing
contaminant microorganisms and/or low log moisture


Moisture content (MC) may be measured by either 1)
cutting a disc of wood from the end of sample logs,
recording fresh and then dry weights and calculating the
percentage moisture; or 2) using electric moisture meters
for rapidly determining internal log moisture levels. To
use the disc method described by Field and Forest
Products, select several logs and cut a 6-inch section
from one end of each log. Cut an additional 1-inch disc
from the log and record its fresh weight (FW) as well as
that of its companion log.

Transfer the disc to an oven and heat at 175F for eight
hours with the door slightly ajar, remove and reweigh.
Dry it for an additional hour, again in the oven, and
reweigh. If there is no further weight loss, the end point
or dry weight (DW) has been reached.

Use the following equations to determine log moisture
---_ x 100 = % MC

If the MC value is below 35%, then the logs should be
watered immediately to ensure adequate internal moisture
for survival and growth of the fungus.

To further monitor the log moisture content during the
growing season, label the companion logs from the
previous analysis and calculate the DW of each entire

Page 4

Growing Shiitake Mushrooms (Lentinus edodes) in Florida

This calculated oven dry weight (CODW) is obtained by
the following:
MC x log fresh weight
CODW = log fresh weight M x l

Record this value on a tag attached to each log and
return these "check" logs to the laying yard.

It is easy to weigh the entire log at any time and
calculate log MC using the following equation:

Current MC = log current weight CODW 100
log current weight

For example, a 1-inch disc is cut and the FW equals 4
oz. After drying, it weight 2 3/4 oz. By the following:

4 2.75
4 x 100 = 31%MC

The fresh weight of the companion log from which the
disc is taken is 15 lbs and the CODW is then:

CODW = 15 bs MC x log fresh weight

31 x 15
= 15 31 x 15 = 10.35 lbs

If you wish to monitor log MC several weeks later, then
weigh the check log and substitute the new log fresh
weight value (14.50 lbs) into the following equation:

Current MC = log FW- CODW 100
log FW

14.50- 10.35
x 100 = 29% MC

Knowing the current MC of shiitake logs is a critical
aspect of production, since periods when MC is less than
30 to 35% are not sustaining fungal development and
thus are reducing the potential fruiting capacity of the
logs. Logs will surely need more frequent replacement
of moisture during hot, dry periods in the spring and
summer than at other times during the year. The goal of
an intensive watering regime is to maintain log moisture
levels high enough for suitable growth of the fungus. If
these moisture levels are in balance with the evaporative
demand imposed by the local climate, then the incidence
of contaminating surface microorganisms and shrinking
or checking of the log surface are minimized.


"Fruiting," or the production of mushrooms generally
will occur under natural conditions mostly in the fall, but
sometimes in the spring in northern Florida as the logs
becomes older and the colonization becomes more
complete. As cold fronts pass through the area at these
times, rainy, cool weather generally will induce fruiting
(Figure 3). At temperatures of 60 to 70'F, logs will
generally not fruit more often than every 30 to 45 days
under favorable conditions. Commercial operations
generally "force" logs to fruit every six to eight weeks
by soaking the logs in chilled water for one to three days
or by sprinkling with cool water for the same period.

Once mushroom formation, or "pinning" begins, it may
take two to eight days before mushrooms are ready to be
picked, depending on ambient relative humidity and
temperature. Shiitake mushrooms should be harvested in
the afternoon when the mushroom caps are dry and
should be refrigerated immediately. The shelf life of
refrigerated fresh shiitake mushrooms, picked at
optimum condition, may be two weeks or more. Some
buyers prefer dried shiitake because of increased storage
time and enhanced flavor characteristics. The
mushrooms may easily be prepared for long-term storage
by air-drying in a warm oven or by using the
dehydration cycle in a microwave oven. After removal,
dried mushrooms should immediately be stored in sealed
containers to prevent reabsorption of water and the entry
of contaminating fungi. Average yields of one pound or
more per log per harvest may be expected until complete
rotting of the log occurs or the log is overtaken by
contaminating fungi.

Page 5

Growing Shiitake Mushrooms (Lentinus edodes) in Florida


Not all mushrooms which grow on shiitake-inoculated
logs may be L. edodes. The grower must become
familiar with shiitake mushrooms either by observing an
existing operation when fruiting occurs or by purchasing
shiitake in the market. The process of inoculation is
designed to overwhelm the log with L. edodes so that
shiitake mushrooms are favored, but this may not totally
exclude mushroom formation by other fungi, including
related species of Lentinus which are found in Florida.
To ensure customer satisfaction and guard against the
sale of non-shiitake mushrooms, the grower must
establish the identity and quality of the product. If any
questions arise concerning the identity of any mushroom,
please contact Dr. James Kimbrough, Plant Pathology
Department, University of Florida, Gainesville 32611

Growers' organizations have formed once local supplies
begin to accumulate to handle large volume sales. The
Florida Mushroom Growers' Association is the primary
association in the state. Sales of fresh shiitake may be
handled by individual producers through grocery store
chains, health food stores, and oriental food markets.
While the American consumer is relatively unfamiliar
with shiitake, increasing supplies should stimulate
consumer interest and increase demand.

While producers in the northern states experience a final
fruiting each year in late August or early September,
Florida growers may be able to extend production much
later and may eventually time production schedules so
that fresh mushrooms are available for Thanksgiving or
even Christmas holidays. Also, dried shiitake tastes as
good or better than fresh, which allows the producer
maximum flexibility to sell mushrooms when prices are
high. Wholesale prices for fresh shiitake in the spring of
1995 were approximately $5.00 per pound and ranged
from $12 to $17 per pound for dried mushrooms.

Recipes for shiitake mushrooms are appearing with
greater frequency in magazines and newspapers. One
that should interest Floridians is printed in this

Current research on production

A research project conducted by the University of
Florida and Florida A&M University has recently been
initiated to improve shiitake production technology in
Florida. Tests have been installed in Taylor and Marion
counties and at the Live Oak Agricultural Research and
Education Center. This project should provide the
necessary data for optimizing mushroom production

during the next several years. Further information may
be obtained by contacting:

Dr. Nancy Arny
School of Forest Resources & Conservation
342B Newins-Ziegler Hall
University of Florida
Gainesville, FL 32611
(904) 846-0882 or

Dr. James Kimbrough
Plant Pathology Department
1453 Fifield Hall
University of Florida
Gainesville, FL 32611
(904) 392-2158 or

Mr. Clay B. Olson
Taylor County Extension Director
108 N. Jefferson St.
PO Box 820
Perry, FL 32347-0820
Phn (904) 838-3508
FAX (904) 838-3516

Sources for more information

Kaye, G.C. 1984. Wild and exotic mushroom cultivation in
North America. Farlow Reference Library and
Herbarium. Harvard University. Cambridge, MA 02138.
32 pp.

Kerrigan, R. 1982. Is Shiitake Farming for You? A Technical
Manual for the Commercial Farmer and the Home
Grower. Far West Fungi. Goleta, CA 93116. 22 pp.

Kuo, D.D., and M.H. Kuo. 1983. How to Grow Forest
Mushroom (Shiitake). Mushroom Technology Corp.
Naperville, IL 60565. 108 pp.

Leatham, G.F. 1982. Cultivation of shiitake, the Japanese
forest mushroom, on logs: A potential industry for the
United States. Forest Products Journal 32:29-35.

San Antonio, J.P., and P.K. Hanners. 1983. Spawn disk
inoculation of logs to produce mushrooms. HortScience

Singer, R. 1961. Mushrooms and Truffles. Interscience
Publishers, Inc., New York, NY.

Stamets, P., and J.S. Chilton. 1983. The Mushroom Cultivator.
Agrarikon Press, Olympia, WA. 415 pp.

Page 6

Growing Shiitake Mushrooms (Lentinus edodes) in Florida

Yoo, B.W. 1976. How to Grow Oak Tree Mushroom Shiitake.
Dr. Yoo Farm. College Park, MD 20740. 21 pp.

Sources for spawns and supplies

Allied Mushroom Products
PO Drawer 490
Tontitown, AR 72770

Field and Forest Products
N3296 Kozuzek Road
Peshtigo, WI 54157

Garden Properties, Inc.
PO Box 722
Bryn Mawr, PA 19010

Mushroom Technology Inc.
PO Box 2612
Naperville,, IL 60565

Far West Fungi
PO Box 1333
Gaoleta, CA 93116

Fungi Perfecti
Box 7634
Olympia, WA 9850

PO Box 220
Summertown, TN 38483

7421 Pudding Creek Dr., SE
Salem, OR 97301

Northwest Mycological
702 NW 4 Street
Corvallis, OR

J.B. Swayne Spawn Co.
PO Box 618
Kennet Square, PA 19348

Sohn's Oak Forest Mushrooms
PO Box 20
Westfield, WI 53964

Won Shan Mushroom Farm
Rt 1 Box 510
Catlett, VA 22019

Growers Association

Florida Mushroom Growers' Association
c/o Charlie Tarjan
3426 SW 75 Street
Gainesville, FL 32607

Page 7

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