Turn your Compost into Mushrooms!

Mushroom cultivation may seem daunting and mysterious, but with time and effort, unused shady spots can become productive mushroom farms.   Urban permaculture can be challenging.  We are constantly presented with “less than ideal” growing conditions: three hours of sun a day and contaminated soil are just a few examples.  The freeway underpass lined with chain-link fence, the old Superfund site where school buses were maintained, a shady weed ridden ally. Hopefully the process described below will inspire you to start utilizing some of these less desirable zones and grow pounds of mushrooms at the same time.

Shaggy Mane

The Story of the Shaggy Mane

For my Dad’s 60th birthday I gave him the idea of a present.  A small note with a few well-intentioned drawings of mushrooms sprouting up around our property.  For the last 2 months Isaac and I have been deep in the laboratory, sterilizing, inoculating and building an army of mycelium.  Isaac has been cultivating oyster, shiitake and reishi mushrooms for years and is incredibly knowledgeable.  He has been a great mentor and leader for my journey into the world of fungus.  We chose three species of mushrooms to cultivate in outdoor patches and oak logs: The Garden Giant (Stropharia rugosoannulata), Shiitake (Lentinula edodes) and the Shaggy Mane (Coprinus comatus).  This first post will focus on our experience cultivating the Shaggy Mane.

Note: Mushrooms are fascinating creatures that are more closely related to humans than plants.  They form giant mycelial webs that function as a “forest internet” transporting information and nutrients to different plants.  Mycelium is the white mold like strands that collect nutrients.  Mushrooms are the actual fruiting body that contain reproductive spores.

Step 1:  Making Agar

We started with a master Shaggy Mane culture that can be purchased at Spore Works or for a far more expensive, but commercially rigorous strain: Fungi Perfecti. Rather than extracting massive amounts of mycelium from the master strain, we started by brewing up some agar solution.  This way, a small portion of the master strain can be grown out before being added to the growing substrate.

To make Agar (mushroom food) we used this recipe: Potato Dextrose Yeast (PDY).  Isaac uses a whiskey bottle with a hole in the cap to pour the piping hot agar into sterilized petri dishes.  Let the Agar cool overnight.

Step 2: Inoculating the Agar

Wait a couple days for the Agar to set.  Before we inoculated the plates we inspected them to see if the agar had cooled and molded evenly.  Keep an I out for the evil Trichoderma, the most common fungi contaminating mold.

We used a home-made sterile glove box to inoculate the agar plates.  Using a scalpel we cut “sunflower seed size” pieces of mycelium from the master colony and placed it onto the agar plates.  Being sterile is really important.  Bring a towel soaked with rubbing alcohol  into the glove box with you to clean the scalpel in-between inoculations.  Once each agar plate has been inoculated, re-wrap the petri dishes in cellophane and put them somewhere dark and warm.

Step 3: Sterilizing the Substrate

Pressure Cooker

So much birdseed!  Wild birdseed is high in nutrients and cheep.  Before introducing the mycelium into the birdseed it must be sterile.  Fill  wide-mouth quart mason jars with birdseed that is soaked to the consistency of a dry sponge. Drill four small holes into the metal top of the mason jar.  You’ll need to get some tyvek from somewhere, packaging envelopes work pretty well.  Cut large squares that can fit completely over the top of the jar.  The order  is Jar, tyvek square, screw top, tinfoil.  Unscrew the jars a quarter turn from tight and  put them in a pressure cooker.  The pressure cooker is probably the most expensive investment in the whole process.  I suggest looking on craigslist.

To start the cooking process, fill the pressure cooker  a fourth of the way full, put it on the stove with the pressure valve open until it gets heated up and then after it hot close the valve.  Lower the stove to medium heat.  Aim to cook the bird seed for at 15 psi for 60 minutes.  Here is a great step by step documentation of sterilizing birdseed (by a blogger growing magic mushrooms).

Step 4: Inoculating the Substrate

Mycelium on an Agar Plate

Back to the glove box!  Scalpel pieces of the agar quickly into the sterilized mason jars and seal them  back up.  The more meticulous and obsessive you are the better.

Step 5: Feeding the Machine!

After three or so weeks the mycelium will run through the birdseed and create something that looks like this:

Healthy Mycelium

Before transferring the Shaggy Mane mycelium make sure you have about 6 shovel full of decomposed horse manure and compost.  Drill holes in the bottom of a plastic tub for drainage.

Plastic Tub

Drilling the holes with a hole saw!

Drill Holes

Smell the substrate.


Gavin Smelling the Compost

Mix it up all nice.

Isaac Mixing the Substrate

Open up the jars and spread the mycelium in layers (lasagna style) throughout the substrate.

Spreading the Mycelium

Put the tub somewhere dark and dry.  In a month, check to see if the mycelium has spread through the compost.  Have a spot picked out on your property where you can mix a big pile of compost and decomposed horse manure.  Layer the inoculated substrate in lasagna style and let it sit.  If built correctly, the patch should produce for years.  Make sure to add more manure and compost each year and you will have shaggy manes for a long time.

I understand this process may seem daunting for the first time mushroom grower:

I’ll let you know how the Shaggy Mane harvest turns out.

Over and Out.

1 Comment

Filed under Fungi, Outdoor Cultivation, Permaculture, Projects

One response to “Turn your Compost into Mushrooms!

  1. Wow, that’s intense! I love how you say that the pressure cooker is the most esoteric gear for this set up, as opposed to the glove box. That fills my heart with glee.

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