The Casing Technique
for Increased Mushroom Production
Mushroom spawn: Definition: the mycelium, or primary filamentous
growth, of the mushroom; also cakes of earth and compost/manure containing
this growth, which are used for propagation of the mushroom.
The Life Cycle of a Cultivated Mushroom:
First, one must grow the spawn of the mycelium. Grain such as rye
is often used for this task. While the spawn is starting to grow,
composting of the manure takes place. Components such as manure, straw,
chicken droppings, and/or turkey droppings can all be added to the
mixture (but not acidic pine needles). Once this compost reaches the
proper temperature, mushrooms growers will add the spawn to the nutrient-rich
In turn, the mycelium will run all throughout the compost eagerly
digesting the organic material. In order to coerce the fungus into
creating mushrooms, a low-nutrient casing is placed on top of the
compost. Thinking it is about to run out of food, the fungus will
produce fruiting bodies (mushrooms) to disperse spores. When just
the right time has come, harvesters will come along and cut the mushrooms
away from the mycelium.
What you will need:
Hand Spray Bottle
Grow Chamber with Cover
(Horse or Cow Manure, Compost/Manure mix, Peatmoss or Coco Fiber)
Water: Spring water only.
(This will be used to help control any green mold that might sneak
up on you.)
'Casing' is a very easy process and the sterility is not of great
importance anymore because the mycelium in your jars has matured and
is capable of fighting off most invading spores and bacteria on its
own. Proceed with common sense and cleanliness!
The supplies you need to get together for this step are, compost/manure,
vermiculite, a spray bottle of Spring Water, a large mixing bowl,
a large metal (not wood) spoon, your growing chamber and the fully
colonized substrate jars of mycelium. Make sure you have all of these
supplies in one place before you begin the next step.
Mix 1 part Peroxide with 20-part Spring Water. Place it into the spray
bottle and sit it aside. This liquid mixture will help with the controlling
of contamination within the compost/manure.
In the mixing bowl, add 1-part compost/manure to 1-part vermiculite
(50/50). Try 3 cups of each to start with. If this is not enough mix
then, by all means, mix some more. If you have any dry mix left you
can place it into a Ziploc baggy and save it for another day. Mix
these ingredients together using the large spoon until they are well
combined. Using the spray bottle of the Peroxide and Spring water,
lightly spray the mixture and stir it until the compost/manure is
moistened to field capacity, meaning that if you take a handful of
this mixture in your hand and squeeze it into a ball it will hold
its shape but no water will drip out. We want the mixture moist but
Pour the mixture into the growing chamber and spread it level on the
bottom (at least one inch deep) with your CLEAN HANDS (use anti-bacterial
soap). Remove the lids from one of your colonized substrate jar and
dump the 'cakes' on top of the compost/manure mixture on the bottom
of the chamber. Using freshly washed hands (2nd washing w/soap), crumble
the cake into small pieces (about the size of marbles) and spread
it evenly onto the compost/manure. If you need to apply a second,
or third colonized jar in order to finish the layering, then do it.
Best to have a little much then not enough.
Put 3-6 cups of plain compost/manure into a clean mixing bowl. Using
the spray water/Peroxide bottle and the large spoon, spray and mix
until your compost/manure has reached the field capacity stage (meaning
that if you take a handful of this mixture in your hand and squeeze
it into a ball it will hold its shape but no water will drip out.
We want the mixture moist but not saturated). Pour this onto the crumbled
cakes and spread level with the spoon. You want to have about 1/2-inch
of even compost/manure when finished. What you should have now is
a three layer sandwich. Bottom layer being compost/manure/vermiculite,
center layer being crumbled up mycelium/substrate cakes and top layer
being plain pre-moistened compost/manure. Put the plastic lid on the
Place the growing chamber into a closet or under your bed and leave
it alone for 7-10 days at room temperature. It does not require any
light during this time, but if they do get light it is fine, just
not necessary. As the white mycelium begins growing through the compost/manure
it should resemble the picture below.
It is now time to remove the lid from your growing chamber and let
the compost/manure breathe some extra fresh air. By now you should
have a white fungi (mold) growing across the surface of the compost/manure.
This is your mature mycelium looking for a place to have its babies
(mushrooms). Remove the lid from your chamber and put it away.
Using your spray bottle of Spring Water, saturate the surface of the
compost/manure. You want the compost/manure to be fairly wet, but
not to the point that your white mycelium will be sitting in stagnant
water puddles. The layer on the bottom of your tray (compost/manure/vermiculite)
should be able to absorb most over watering and release it back into
the compost/manure as needed.
Continue watering the surface once or twice daily as needed. It will
not take very long to be able to know when your chambers need watering
- when the surface is dry, it needs more water. They seem to need
more water during the cold months because of the dry air in your home
produced by your heater. If you have to miss a day of watering for
some reason, you can lay the lid back onto the growing chamber for
a day to allow the surface to re-hydrate.
Within a short time of removing your lid, one day to one week, you
should have several mushrooms popping up. When these mushrooms start
to open up and break the veil under the cap, they are ready for harvest.
Just reach in and grasp the stem as close to the compost/manure as
possible and give a twist, it will pop right out.
This is not a step, just a reminder to keep spraying, and keep harvesting,
until the chamber is no longer producing mushrooms (one to two months).
Contamination of Green Mold!
Note the green discoloration. This is our enemy!
This is a fact of life for the mushroom grower. Green mold is a common
contaminate that can find its way into your growing chamber quite
easily. The key to winning this battle is quick and precise counter
measures. The INSTANT you see green on your casing compost get it
out of there! Flame a spoon or heat it as much as possible from your
stove top. Quickly open the chamber and scoop it out and close the
chamber lid. Re-heat the spoon EVERY TIME it has to enter the growing
Mix 1-part Peroxide with 20-parts Spring Water and place it in a
spray bottle. Spray the newly cleaned area until it is nice and soaked.
Try to keep the mixture contained to the immediate area as much as
If you find that you that you were forced to take away much of the
casing compost, just place some DRY CASING over top of that area and
begin spraying with the solution. Do your best to contain and stay
on top of the green mold until it is completely gone or it becomes
a losing battle.
Another Casing Recipe:
Using peat moss, lime flour, and a baking pan or tinfoil
This recipe is for 1 tray's worth of casing (using a 1'x2' tray about
1" thick casing). The amounts can be increased to make larger batches.
To begin, add about 10 cups of peat moss to a large kitchen bowl.
Next, add 1 1/2 cups of hydrated lime flour. Mix together dry. Next,
add water and mix in. Peat moss will soak up an amazing amount of
water. Keep adding water and thoroughly mixing it in ( by hand) until
you can squeeze a handful and get a small trickle of water to run
out of it.
Put the wetted casing material into your baking pan or tin and cover
tightly with tinfoil. Next, put it in the oven and bake at 300 F for
1 1/2 hrs. When it's done, let it sit overnight to completely cool.
And it's ready to use.