Morel photo by Bob Harris
This technique was developed by mycologist Gary Mills after much trial
and error, and observations of morels growing in nature. What follows is
a sequence which Gary demonstrated for the PBS series, Scientific
American Frontiers. The temperature, humidity, substrate and other
detailed parameters were placed in the public domain by George Robert
Morels are gathered in the woods. Typically this occurs in the early
Spring. They can be very elusive, but look under the corners of downed
trees, in thick leaves, and in areas recently burned by forest
In a clean area (preferably under a HEPA hood), use a sterile
(heat/alcohol-treated) paper clip to pierce the stem of a healthy
Hang the mushroom by the paperclip over a freshly prepared petri
dish. Petris, agar mix and agar preparation instructions can be ordered
Let the morel drip its spores onto the petri plate as you gently
work it with your fingers. If you don't see spores falling, just leave
the mushroom hanging over the agar.
Cover and seal the agar plate and store it (at 55-80°F). You
can invert it to prevent moisture from building up on the lid. After a
period of from a few hours to a few days, the spores will begin to send
out their first mycelial strands into the agar plate
The strands will form a web, and then grow vigorously, extending
over the entire plate. For maintaining rapid growth as we transfer to
new media, the most valuable portion is the outer, leading edge where
thin strands are extending most quickly.
When the plate is fully colonized, you can either transplant
sections into fresh agar, thereby propagating the culture indefinitely,
or you can innoculate grain media with sections of the mycelia you cut
from the plate, using a sterilized (alcohol and heat treated) razor
knife. Resterilize the knife after each transfer.
A good grain medium is annual rye grass seed. Other grains such as
rape seed, hemp seed, birdseed, and rice will work. Cover grain with
water and soak for 24 hours.
Drain and mix with potting soil, 1 part potting soil to 5 parts
grain. Place 2 cups of this medium into a 1 quart regular canning jar.
(Sorry, the pictures are of a pint jar!)
Fit with filter disc and ring and sterilize for 1 hr at 15 psi in an
Clean work surface with 5% bleach, use a laminar flow hood, if
possible. Remove filter disc from jar and quickly add a few small
pieces of agar cultured mycelium with a flame sterilized scalpel.
Replace filter disc. Cover the filter disc loosely with foil to prevent
drying of the culture. Resterilize your scalpel after each transfer.
Shake the jar to thoroughly mix in the mycelium. Place the jar in a
cool (68 - 71°F), dark place for approximately 4 - 6 weeks. Good
growth will be indicated by whitish strands of mycelium growing through
the medium. At about 5 weeks, small aggregates of white to rust colored
mycelia scerotia will form.
After the schlerotia are visible within the jars, prepare some clean
trays to receive the mixture for fruiting. Construct a fruiting room
where temperature, humidity, light and fresh, filtered, air can be
precisely controlled. The Mushroom Cultivator by Stamets and
Chilton has excellent ideas on growing rooms.
Make a fruiting substrate mix of 20% sand, 30% potting soil, 50%
organic material composed of 80% small hardwood chips (ash, oak, maple,
beech, elm, apple, etc.), 10% rice hulls, 5% soybean meal, 5% sphagnum,
and a small amount of lime (the mineral, not the fruit) to bring the pH
to 7.1-7.3. Mix well.
Fill an autoclavable aluminum 9-1/4 X 9-1/4 X 2-1/2 inch tray (i.e.
cake pan) or plastic dishpan (liberally punched with drainage holes) to
a depth of 2 inches with substrate.
Saturate substrate thoroughly with water. Allow to drain
completely. Fill a second, identical tray with soaked, drained rye grass
seed to a depth of 1/2 - 1 inch. Set substrate tray into rye seed tray
so that the bottom of the substrate tray rests on the rye seed. Place
the prepared trays inside an autoclave bag (oven cooking bags seem to
work well) fitted with a filtered closure and sterilize at 15 psi for at
least one hour.
In a clean (use 5% bleach to clean up) draft- free area (laminar
flow hood recommended) open cooled substrate bag and mix ca. 1/2 cup
spawn into substrate using a flame-sterilized spoon. Reclose bag and
place in a cool (65-70°F) dark place for 4-6 weeks. During this
period (the spawn run) the relative humidity should be kept at 90-100%,
CO2 at 6000-9000 ppm, and no fresh air exchanges.
After 4-6 weeks, the surface of substrate should be covered with
sclerotia. The hard schlerotia lumps are the secret to growing morels.
These are the "seeds" of your mushrooms. Keep unused spawn refrigerated
at 38-40°F. Spawn is viable for up to a year, under optimal
CHILLING (a necessary step): After spawn run, remove rye seed tray
from bag, reclose, and place bagged substrate tray into refrigeration (38-40°F) for
Remove bagged tray from refrigeration. Remove substrate tray from
bag and place in fruiting chamber or room. Slowly saturate substrate
with sterile (65-70°F) water at a rate of 1.5-2.5 fluid
ounces/hr/square foot of substrate surface area for 12-16 hours. Allow
substrate to drain completely (for about 24 hours).
CASING (optional): Layer casing soil evenly to a depth of 1/2". Allow
7-10 days for mycelium to run through the casing. Air temp 65 -
70°F. Filtered fresh air exchanges at 1 - 2 per hour. Keep dark.
Primoridia will form in 3-7 days. Substrate moisture 60%, relative
humidity 95-100%, air temp 70 - 73°F, filtered fresh air exchanges
6 - 8/hr. Light cycle 12 on / 12 off (grow lights). Keep CO2 less than
FRUIT BODY MATURATION: Substrate moisture 50%, relative humidity
85-95%, air temp 73 - 77°F. filtered fresh air exchanges 6 - 8/hr.
Light cycle 12 on / 12 off (grow lights). Keep CO2 less than 900 ppm.
You can also grow outdoors using sawdust spawn available from Mushroompeople. Plant Spring through Fall. Inoculated
area must be kept moist during hot, dry periods.
Plant under the type of trees where you find morels in your area, i.e.
ash, oak, maple, beech, elm, old apple orchards, etc., in your garden
with perrenials such as jeruselum artichoke or asparagus.
HOW TO PLANT: Gently remove forest litter from 7-8 square foot area for
each pound of spawn to be planted. Loosen soil to a depth of 1 - 2
inches and moisten lightly, if dry. For each 7 - 8 square foot area,
add 1 pound (soaked 48 hours) wood chips (from above types of trees) to
loosened soil. Next, break up spawn and distribute evenly over prepared
areas. Mix lightly with wood chips and soil. Replace litter and keep
moist, especially during hot, dry months. Supposedly, a cover crop of
clover helps to keep soil moist and adds nitrogen to the soil.
WHEN THEY FRUIT: Late April - early June. Fruiting should occur the
spring following planting. If you have a dry spring, be sure to water
the planted area.
Cook 'em up! For a section of excellent cookbooks, visit our on-line catalog!
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