Growing Shiitake Mushrooms

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ILLUSTRATION: MOTHER EARTH NEWS STAFF
The author built this mushroom cage to facilitate the process of growing shiitake mushrooms.

In ancient China and Japan, the savory shiitake
(it’s pronounced “she-tar-kee”) mushroom was reserved for
royalty, and its deep forest habitats–where the fungi
grew wild on the logs of shii trees and other
hardwoods–were closely guarded. Then, some thousand
years ago, Japanese farmers began growing shiitake mushrooms. Today the island nation
exports more than three million pounds of the
firm, slightly chewy morsels every a
year to countries all over the world.

These gourmet treats (which are much more flavorful than
the commonly available white button mushrooms) are an
excellent source of high-quality protein, fiber, vitamin C,
the B vitamins, calcium, phosphorus, iron, and trace
elements … and contain even fewer calories than do
apples. Furthermore, clinical tests have demonstrated the
shiitake’s ability to reduce serum cholesterol in humans by
10-20%, and–when fed to laboratory animals–the
fungi have seemed to help prevent polio and influenza
infections.

Food for All

Besides being a dinnertime treat and a marketable
crop (the food co-ops here in Madison, Wisconsin are eager
to buy all I can produce, at about $2.00 a pound), the
shiitake (Lentinus edodes) can provide food for
your animals. No, the critters don’t eat the
mushrooms (which are far too tasty to be used as
livestock feed) … but they’ll love the straw, bark, and
paper compost that remains after the harvest. These fungi,
you see, are lignicolous: that is, they break down the
lignin that makes such wastes unsuitable for animal
rations, and–at the same time–release vitamins,
carbohydrates, cellulose, and sugars … as well as a
slightly sweet aroma. (In palatability tests, cows and pigs
chose mushroom compost over conventional feeds every time!)

Though the mushrooms should ideally be eaten within two
days after they’re picked, they do keep longer than the
common white variety and are easily dried whole in a
140°F oven or–better yet–outdoors on a hot
day. To reconstitute them, simply soak the fungi for 20 to
30 minutes in cool water or for 15 minutes in
hot water. They won’t swell up very much, but will
become quite pliable.

Shitake Cultivation

The best “culture” on which to grow the shiitake contains
straw, corncobs, 10% oak bark (an important ingredient),
and up to 50% paper. Oat hulls, sawdust, and other similar
farm wastes can also be employed, but–whatever you
use–be sure to grind the material up well.

Of course, you’ll also need mushroom seed (or
spawn, as it’s properly called). This can be obtained from
The Kinoko Company. Use about one ounce
(28 grams) of spawn per pound of dry waste. If you purchase
already seeded wood chips, simply allow five to ten chips
for each standard compost container.

To construct your “tray”, make a frame from softwood 1 X
6’s (mine is 2′ X 3′), being sure to use waterproof glue.
Staple a screen of wire mesh (with 1″ to 2″ holes) to one
side of the frame, and then affix 12 storm window clips to
hold another (removable) piece of wire screen to the back.
For convenience, a metal handle can be fastened to the top
(one of the shorter sides).

Now, pack the tray well with the compost mixture and pour
boiling water–about a gallon for every pound of dry
material–over the waste. (This should be done in an
old tub so that the straw can soak up the water.)

An alternative method is to heat a large drum of water to
boiling and “dunk” the entire loaded tray. (This technique
is preferable when more than one container is being
“pasteurized”.) After several minutes remove the tray from
the water, allow it to drain, and cover it with a
clean polyethylene bag (plastic trash bags work
fine).

Plant Your Crop

The mixture should then be allowed to cool to 85°F, a
process which can take from one to three days. At that
point, uncover the tray, remove the wire backing,
and–with clean hands–mix in the spawn.
(If seed-inoculated wood chips are used, simply push them
into the mixture without removing the screen.) Recover the
container with the plastic bag, seal the wrap well, and
allow the cage to sit in a dark place.

After about one week, the shiitake must be exposed to light
for five days. (Sunlight or fluorescent light is fine, but
grow-lights won’t work at all.) Unless clear plastic bags
are used, you’ll have to uncover the container and
administer a daily misting to make sure the compost is kept
moist.

When the exposure time is up, return the tray to the
plastic bag–and to its dark
confines–for six to seven more weeks … which is
the amount of time necessary for the mushroom seed to
spread throughout the compost. This “spawn run” will be
finished once a white growth (called white mycelium) covers the
outer surfaces of the culture.

At that point, uncover the container … turn on the
lights … and wait for the fruiting bodies (the part of
the mushroom you eat) to appear. In a week to ten days,
tiny pins will form and will soon develop into mature
edibles. The tray (or trays) must be kept moist during this
time (a hose with a mist nozzle does a nice job), but don’t
overwater them. (It’s also important that the area be well
ventilated … otherwise the mushrooms may produce long,
tough stems.)

As the one-legged edibles reach the desired stage (they’ll
vary in size from half an inch to two inches across the
caps), cut each of them off at the base with a sharp knife.
After that harvest, a second crop should appear in two
weeks if the tray is kept moist. In fact, you can usually
obtain three or four crops from a single container!

Once production ceases, remove the mushroom compost and
give your livestock a gastronomical feast. Then, before
using the container again, clean it well with hot water and
a scrub brush.

Another Growing Method

If you don’t have critters to feed or a garden that needs
compost–and if you’re willing to wait a year
or two for your first shiitake crop–I’ve found an
easier growing method, one that doesn’t require the
use of straw cultures or cages.

First, in the fall, obtain a cord of oak logs. Then, in the
following spring, drill holes in the wood and pound about
750 spawned wood chips (per cord) into the holes. Stack the
logs in a pile, and–after about a year–the
first mushrooms will appear. This crop won’t be very big,
but by the second year the logs will be covered with
delectable fungi.

Woodpile crops can be harvested in both spring and fall,
and–if the logs are kept cool and moist–you can
sometimes get a good crop through the summer, too. Your oak
stack will continue to produce for four to five years,
yielding a total of about 1,000 pounds of mushrooms. (You
needn’t worry about the effects of exposure to light,
ventilation, or cold winter weather, either, because
the shiitake is pretty hardy.)

Spawn Your Spawn

To save money, you can grow your own spawn, for future use,
from the seed you buy. Just mix oak chips with water, and
process them in a pressure cooker at 15 pounds for 25
minutes. Allow the cooker to cool, open it, drain
off the excess water, and pour the chips into a new,
clean plastic bag. Add a bit of spawn (or a few spawned
wood chips) and seal up the sack. After a couple of months,
the chips will be covered with seed and ready to use.
(Always remember to reserve a couple of chips from each
batch to produce more.)

You’ll find these mushrooms a delight to eat,
since–besides seasoning the dish in which they’re
used–they retain their own unique taste. (Include
them sparingly at first, because the shiitake’s flavor is
much stronger than that of its supermarket counterpart.)

“Mushrooms are the fastest-growing agribusiness in this
country,” says fungus expert Gary Leatham, “but–as
people find out how good such exotics as shiitake
are–many shoppers will give up the white button
mushroom. When that happens, the small-scale farmer will
reap the benefits.”