Home production of shiitake (she-TAH-kee) mushrooms can be a
rewarding and delectable hobby. They can be grown year-around
indoors and out; on hardwood logs or blocks of sawdust; with a
concerted all-out effort or just casually. You will never get
mushrooms this fresh from the supermarket produce section.
Shiitake mushrooms are good to eat, an excellent source of
protein, trace minerals, B and D vitamins, and low in both fat
and calories. Shiitake mushrooms also have been proven to reduce
Shiitake mushrooms do not bruise easily and can be stored for
up to a month if harvested at the right time and refrigerated in
"vegetable bags." They can also be dried and stored in sealed
plastic bags for up to 2 years.
Growing shiitake mushrooms does require patience. You can
establish a shiitake garden by purchasing or cutting your own
logs in the dormant season, and inoculating them yourself. It
will take 6 to 12 months for these logs to produce mushrooms. For
those with less patience, you can buy sawdust blocks or
preinoculated logs. You should be able to fruit them right
Picking The Right Shiitake Strain
If you inoculate the logs yourself, order your spawn (the
form of the shiitake fungus that grows through the log) from a
reputable dealer 1 to 2 months before you plan to cut your trees.
Spawn producers may not have the most desirable strains available
if you wait too late to order. Give the spawn dealer your desired
shipping date so your spawn will be as fresh as possible.
Fruiting Temperature Requirements
There are several shiitake strains (varieties) available.
They are usually categorized by fruiting temperature
requirements. Shiitake will generally fruit (form the edible
mushrooms) at log temperatures between 41 and 86 degrees F.
· Cool season strains fruit at 41 to 68 degrees
· Wide range strains fruit at 50 to 80 degrees F.
· Warm season strains fruit between 50 and 86 degrees
Strains may also vary in productivity, appearance, mushroom
size and length of time it takes to fruit.
Select strains that will fruit in the environment where you
plan to develop your shiitake garden. If you plan to use the
shade of a maple tree, inoculate logs with a warm season strain
for summer fruiting. If you want to harvest mushrooms in winter,
inoculate logs with a cool season strain. A wide range strain can
be used for spring and fall production. Logs grown indoors should
be inoculated with a strain that grows at the temperature of the
growing room you plan to use.
Condition and Appearance Of Spawn
All strains can be purchased as sawdust or dowel spawn
(Figure 1). Your spawn should be white and fluffy when you
receive it (Figure 1). There should be little or no liquid in the
bottom of the bag. If there are green patches (Trichoderma, a
weed fungi), contact the vendor and ask for new spawn.
Figure 1. Dowel (left) and
sawdust spawn (right) are used for log
If the spawn is brown and loose, the mycelium is not well
knitted and it was sent to you before it was ready for you to
use. You can store unknitted spawn at about 65 to 70 degrees F in
a moist environment for a few weeks, to see if it will turn
white, or you can return it and ask for your money back or a
white bag of spawn. If you receive your spawn more than a few
days before you plan to inoculate, you should place it in the
refrigerator or a very cool basement. Move spawn to room
temperature about 24 hours before you plan to inoculate. When
ordering a preinoculated log or sawdust block, make sure you tell
the supplier the fruiting temperature conditions, so you will get
the right inoculated strain.
Selecting The Best Trees
The three types of trees most often used for production of
shiitake mushrooms are white oak, red oak, and sweetgum. White
oaks are the most productive and are bothered the least by
invasions of foreign or weed fungi. But, white oaks require the
most patience, since it usually takes 8 to 12 months from
inoculation before the mushrooms first begin to fruit.
Red oak and sweetgum have softer wood and will produce
mushrooms in 6 to 8 months. They also require more careful
management since they are more susceptible to other fungi, bark
peeling, and rapid water loss.
Shiitake mushrooms will also grow on American hophornbeam,
ironwood, laurel oak, cherry, sassafras, sycamore, tulip poplar,
and hickory. How well the shiitake mushrooms grow on logs from
these trees depends on how much care you give the logs and how
well you control moisture, temperature, and exposure to other
fungi. Other types of trees can be used for growing shiitake
mushrooms, but under the best of conditions, you will only
harvest a few mushrooms per log.
The actual location of the growing tree is also important.
The more fertile soils will produce trees with more nutrients and
sugars. Trees located on rocky hillsides and in very wet sites
are less nutrient rich.
Area Of Sapwood
Since shiitake mushrooms feed primarily on sapwood, trees
selected for inoculation should have a large sapwood area. You
can determine the area of sapwood by looking at the end of a log
after the tree has been cut. Most of the trees in a particular
area will have similar sapwood to heartwood ratios. The lighter
or outermost wood is the sapwood and the darker or inner wood is
the heartwood (Figure 2). A small amount of sapwood means that
the log will probably produce mushrooms for less than 2
Figure 2. The
lighter, outermost wood is the sapwood and the darker, inner wood
is the heartwood.
Cutting And Buying Shiitake Logs
Logs should be harvested during the dormant season from live,
healthy trees. Cutting your own logs is an option only if you
have a chain saw and easy access to hardwood trees. Be sure you
take a buddy along if you cut your own logs. If you can, cut the
tree down 7 days before you plan to inoculate. Logs can then be
cut to size and moved to the inoculation site immediately.
Trees left in the woods should remain uncut and untrimmed for
7 to 10 days. Then, cut them to size and inoculate within a few
days. The diameter and length of the log will depend on how heavy
you want your logs. A log 40 inches long, 8 inches in diameter
will weigh about 60 pounds. A log 40 inches long, 4 inches in
diameter will weigh about 25 pounds.
Buying logs to inoculate can be difficult because the logs
must not be split or the bark damaged. They must also be of the
type, length, and diameter you specify. Most log cutters will
charge from $0.50 to $1.00 for a log 40 inches long and 4 to 6
inches in diameter. Agree to accept and pay for only those logs
meeting your specifications.
The mushrooms can be harvested at any time by cutting or
twisting the stem off of the log. However, mushrooms are best if
harvested shortly after the gills are exposed (Figure 14).
There are several tools necessary for inoculation and there
are some that just make inoculation easier. Where possible,
several options for equipment or supplies have been given (Figure
Figure 3. Equipment and
supplies used for inoculation of logs. From left to right: cheese
wax, propane stove, wax pot, wax baster (front), foam plugs
(front), propane canister (rear), inoculation tool (front) spawn
(rear), high speed drill, 716 inch bit with collar stop and screw