Summertown, Tennessee, USA


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 Trager

Step 1.

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 fire.

Step 2.

Keep the morels fresh as best you can by keeping them in a bag or box in the field, then refrigerating them when you get home.

Step 3.

In a clean area (preferably under a HEPA hood), use a sterile (heat/alcohol-treated) paper clip to pierce the stem of a healthy looking mushroom.

Step 4.

Hang the mushroom by the paperclip over a freshly prepared petri dish. Petris, agar mix and agar preparation instructions can be ordered from Mushroompeople.

Step 5.

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.

Step 6.

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

Step 7.

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.

Step 8.

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.

Step 9.

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.

Step 10.

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!)

Step 11.

Fit with filter disc and ring and sterilize for 1 hr at 15 psi in an autoclave.

Step 12.

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.

Step 13.

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.

Step 14.

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.

Step 15.

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.

Step 16.

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.

Step 17.

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.

Step 18.

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.

Step 19.

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 conditions.

Step 20.

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 two weeks.

Step 21.

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).

Step 22.

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.

Step 23.

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 900 ppm.

Step 24.

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.

Step 25.

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.

Step 26.

Cook 'em up! For a section of excellent cookbooks, visit our on-line catalog!

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