PREPARING TO GROW
OYSTER MUSHROOMS:
FACILITIES
The cultivation of mushrooms is an art, but it is based on science and
technology. Any indevour, which is both an art and a science requires both
study and experience. However, those who plan to grow mushrooms can be
split into groups based on several factors. Maybe the most useful way to split
them is to consider what they want to use:
1.Expertise – a person who has worked on a mushroom farm.
2.Waste materials he sees.
3.Waste materials from his own farm or other business.
4.A building he owns, or can get cheaply.
Most people would expect the first to be the most likely to succeed,
but you may be surprised to learn that the entire list is in order of expected
2
OYSTER MUSHROOM CULTIVATION
success. Many waste materials work, but mixtures are generally better than
any single waste. Most farmers who have wastes have other activities that
they must pay attention to. So although they may be dedicated in spirit, they
can not be completely dedicated to mushrooms. There are exceptions, but
most buildings looking for a use, are not good places to grow mushrooms.
It is good to have wastes that mushrooms like to grow on, but there are
plenty of wastes in almost every culture. The most important thing a
mushroom grower needs is knowledge of how to grow mushrooms.
Mushrooms are more like pigs and cattle than like wheat, or potatoes. Yet,
like wheat and potatoes, everything they need must be available exactly where
they are. However, it is not even that simple. Food for mushrooms is food for
other things and mushrooms themselves are easy prey. Animals and plants
both have skin that protects them. Mushrooms have little protection except
that once established they are fierce competitors. The most important tool
that the mushroom grower has is sanitation.
Even if the experienced individual needs help, discussing his needs
will do little help others. More discussion of wastes will be useful, but we
need to have a place to grow the mushrooms, or it will be difficult to do
much. So let us begin by discussing buildings. The buildings are the physical
protection for the mushrooms.
The reason most building looking for a use are a poor choice is because
they do not provide the things the mushrooms need. It should be apparent
that if most building are inadequate, mushrooms have special needs. How
will we learn their special needs? One of the very best ways to learn the
needs of living things is to observe the conditions where they grow normally.
THE NATURAL ECOLOGY OF MUSHROOMS
Oyster mushrooms are found wild in temperate forests and some species in
tropical forests (
Fig. 1). Typically, they grow on dead logs, one relatively
uncommon species attacks weak living trees. We would, therefore, expect
logs to be the best substrate, but we have found that straw and some other
ligno-cellulosic wastes are better for cultivation. Forests are generally moist
3
CHAP 1 FACILITIES
Fig. 1.
Oyster mushrooms (Pleurotus) in a natural, wild environment.
4
OYSTER MUSHROOM CULTIVATION
Fig. 2.
Agaricus growing in the wild - grass.
places with dim light. Logs are sometimes buried by other forest debris. The
survival of the species depends on the ability of mushrooms to protrude above
the surface. Oyster mushrooms have evolved to use low carbon dioxide
concentrations and light as indicators that they have reached above the surface.
However, the trees filter out much of the light and blue light predominates,
so mushrooms respond only to blue light. Many other wood inhabiting
mushrooms have very similar needs.
Relatives of the common commercial mushroom are found in more
open places and are associated with manure and already rotting debris (
Fig.
2
). While open places might suggest a need for light, we have found that
Agaricus
and other mushrooms associated with already rotting materials do
not use light, but depend primarily on gravity as a signal to grow away from.
5
CHAP 1 FACILITIES
Carbon dioxide is also avoided. Wind is more likely to remove carbon dioxide
in the open. Probably, it is also more likely to benefit from photosynthetic
removal of carbon dioxide by grass and other small plants.
We can not get all answers necessary to describe the environment,
simply from observations in the wild, but we can see that there are special
requirments for envionments that we should be prepare to deal with in our
buildings and in the other parts of our cultivation environment.
BUILDINGS AND OTHER FACILITIES
We have said that most ordinary buildings are not suitable for mushrooms.
Oyster mushrooms have some basic requirements for the environment
provided by the growing-buildings:
1.A temperature of 15 to 20°C (59 to 68°F)
2.A humidity of 80 to 95%
3.Good ventilation
4.Light
5.Sanitation
Temperature and humidity should be kept as constant as possible and the
exact needs may depend on the variety. Any rapid changes in temperature
will cause disastrous changes in humidity. At 20°C (68°F) and 90% humidity,
if the temperature drops to 19°C (66°F) the humidity rises to 100%. If the
temperature rises to 21°C (70°F) the humidity drops to 82%. At 15°C (59°F)
the change will be approximately 1% less. That is 99% for 1°C loss and
83% for 1°C increase. The relation between temperature and humidity make
insulation a must. Insulation may be a commercial material, but a thick layer
of soil over a masonry building or straw or even paper between the inner and
outer wall surfaces can be adequate.
At 100% humidity, everything is suddenly wet. Conversely, at 80%
humidity, the mushrooms begin drying. If everything becomes wet, then many
building materials will rot and others will corrode. So growing conditions
6
OYSTER MUSHROOM CULTIVATION
limit our choice of building materials. Concrete and plastic are two materials
that will withstand considerable moisture with little damage. Some growers
use wood or metal structures and cover them with plastic. Others just use
wood or metal and accept its very limited life. The biggest problem with
wood and some other porous materials is that they can harbor diseases and
pests.
Both a good vapor barrier like polyethylene and insulation are needed
to maintain temperature and humidity. In
Fig. 3 we see commercial insulation
in plastic between the ribs (rafters) of a metal building. In Asia they have
built houses of bamboo, polyethylene sheet and used straw for insulation
(
Fig. 4).
Good ventilation is needed for healthy mushrooms and for healthy
workers. Low carbon dioxide is required for mushrooms to form. The stems
of Pleurotus
as well as other wood inhabiting mushrooms will grow until the
carbon dioxide is very low. Centrifugal blowers are generally used to supply
air. The air should be heated or cooled first and then humidity added before
it enters the room. Of course, steam can humidify and heat at the same time.
Ventilation must remove the carbon dioxide formed by the mushrooms, people
and anything else. People can stand almost 10% carbon dioxide, but the
mushrooms are more sensitive. Mushrooms should be picked before spores
are shed, however, even with good management some spore will be released.
Spores can cause asthmatic and hay fever reactions, ventilation can help
reduce the spores in the air.
Light is required for oyster mushrooms and most other tree inhabiting
species. One may read many things about the amount of light, but there have
been very few carefully done experiments. I mentioned that forest light is
blue. I have tried and failed to produce mushrooms with incandescent light.
It is a rather yellow light. Fluorescent lights come in a variety of colors, The
most common are "cool white." With cool white if there is enough light to
read and they are lit 8 hours each day you will have enough light. Natural
daylight does not work well because the temperature will be affected by the
sun. Algae and other plants are more likely to cause trouble in daylight.
Agaricus
, the common commerial mushroom, does not require any
7
CHAP 1 FACILITIES
light and some of the older varieties change color with light. Generally the
only light in the houses are battery operated lights on workers’ helmets.
So, we generally do not want windows in any mushroom growing
buildings. If light is needed by the mushrooms, fluorescent lights are generally
the best light to use. If light is required only by people, battery operated
lights are ususally the most satisfactory.
Sanitation is the most important thing that must be provided by the
building. Sanitation will include:
1. Filtered air in
2. Screen or filters at air exits
3. "Air-lock" changing room
4. Foot bath
5. "Air tight"
Fig. 3.
Building
with insulation
covered by a
plastic vapor
barrier.
ALL openings should provide some means to keep out diseases and pests.
Air exits should have a fine mesh screen or a filter. Air inlets should be
filtered to keep out pests and diseases. A High Efficiency Particulate Air
(HEPA) filter is ideal, but other filters may be completely adequate.
Fig. 5
8
OYSTER MUSHROOM CULTIVATION
shows two excellent furnace/air conditioner filters. If no commercial filters
are available, three layer of muslin or similar fabric will be a good substitute.
Screens or filters should also keep insects out of the air exits. Power failures
and other problems may interrupt ventilation and insects will enter. They can
even fly against the flow of air if it is not fast.
Fig. 4.
Growing
buildings constructed
of
bamboo,
polyethylene
sheet
and straw.
Top
: Thailand
Bottom
: Taiwan
A room for workers to enter the growing facility can be built very
cheaply with a light framework and black plastic film. It can contain rubber
boots, a salt or hypochlorite foot bath and maybe clean clothes, masks or
rubber gloves. The poorest possible source of light for mushrooms is sodiumvapor
lamps. However,
they are extremely efficient
for outdoor lighting. While
they
are efficient
for people. Insects can not see with them, so they are also
9
CHAP 1 FACILITIES
Fig. 5.
Two high quality furnace/air conditioner filters.
good for "air-lock" changing rooms. Yellow colored incandescent light bulbs
are also available, and are adequarte for humans, but are not seen by insects.
If the building can be made air tight, except of the controlled air inlets
and exits, most diseases and insects can be kept out. Insulation foam, silicon
or other caulk can be used to close small openings.
SUBSTRATE INITIAL PREPARATION AREA
Agaricus
requires an area where substrate is wetted and ingredients mixed.
That area is almost always outdoors although often there is a roof with no
walls where front loaders and other machinery can do the heavy work. The
area should always have a concrete surface that can be decontaminated, if it
becomes a source of insects or disease.
Following mixing, the substrate must be composted. That may be done
in the open, usually with heavy machinery to turn it. However, men with
10
OYSTER MUSHROOM CULTIVATION
Fig. 6.
Right: A small hammer
mill (open) showing hammers
and "screen."
Below
: Straw that was chopped
by the hammer mill.
hayforks can do the job. Today most farms are using tunnels or "bunkers".
These are indoor facilities where air is blown up throught the substrate as it
ferments to compost. It is possible to add steam and pasteurize in the tunnels,
as well.
Wood inhabiting species
often use substrates which are more easily handled
if they are first chopped in a hammer mill. Usually the best substrates are
mixtures of several ingredients. The area should be dry, so a roof or more
protection will be desirable for chopping and mixing.
In some cases, the substrate will remain dry until pasteurization takes
place, in others it will be wetted before pasteurization. In still others it will
be wetted and placed in the growing container as part of the preparation.
No mater how the substrate is handled after preliminary preparation,
appropriate space must be available.
11
CHAP 1 FACILITIES
FINAL PREPARATION AREA
Pasturization
requires equipment that can assure that the temperature of
ALL
the wet substrate is 55° to 60°C (131º to 140ºF) for at least 30 minutes.
IT MUST NEVER BE AT A HIGHER TEMPERATURE!
It must also
provide conditions to protect the substrate from fresh contamination and
allow it to cool slowly so that it is about 25°C (77ºF) after 16 to 20 hours.
Sterilization
requires equipment that can assure that the temperature of ALL
the wet substrate reaches 121°C (250ºF) for about 15 minutes. A pressure
vessel is require to reach such temperatures. The substrate must be in
containers the exclude the entrances of all microorganisms. Cooling must be
slow enough so that there is little difference between atmospheric pressure
and the steam or water vapor in the container of substrate.
Sterilization requires much more expensive equipment, much more
fuel and much greater care at every step than pasteurization. It is almost
universally recommended for some species that bring high prices. A few
recommend it for
Pleurotus. However, that suggests that they do not know
proper pasteurization proceedure.
SPAWNING FACILITY
The place where the substrate is pasteurized, cooled, or sterilized must be
maintained with greater sanitation than the growing area. It will probably be
the best place to spawn as well. The air needs to be reasonable for those
working there. But air temperature and humidity need not be controlled
closely. It is ideal to have pasteurization or sterilization and spawning several
kilometers from the growing area. Such an arrangement avoids many sources
of disease and pests. The equipment at this facility is a substantial part of the
whole. However, it will be discussed under the process because there is a
choice of methods and equipment.
12
Mushroom cultivation has many facilities requirements. There are no shortcuts
to those requirements. If the requirements are not met, failure, or at least
poor production is assured. The facilities must provide the environment
required for mushroom growth. The facilities must also provide the primary
protection against insects, other pests and disease. Without the environment
and protection provided by the facilities, management can not p
OYSTER MUSHROOMS:
FACILITIES
technology. Any indevour, which is both an art and a science requires both
study and experience. However, those who plan to grow mushrooms can be
split into groups based on several factors. Maybe the most useful way to split
them is to consider what they want to use:
1.Expertise – a person who has worked on a mushroom farm.
2.Waste materials he sees.
3.Waste materials from his own farm or other business.
4.A building he owns, or can get cheaply.
Most people would expect the first to be the most likely to succeed,
but you may be surprised to learn that the entire list is in order of expected
2
OYSTER MUSHROOM CULTIVATION
success. Many waste materials work, but mixtures are generally better than
any single waste. Most farmers who have wastes have other activities that
they must pay attention to. So although they may be dedicated in spirit, they
can not be completely dedicated to mushrooms. There are exceptions, but
most buildings looking for a use, are not good places to grow mushrooms.
It is good to have wastes that mushrooms like to grow on, but there are
plenty of wastes in almost every culture. The most important thing a
mushroom grower needs is knowledge of how to grow mushrooms.
Mushrooms are more like pigs and cattle than like wheat, or potatoes. Yet,
like wheat and potatoes, everything they need must be available exactly where
they are. However, it is not even that simple. Food for mushrooms is food for
other things and mushrooms themselves are easy prey. Animals and plants
both have skin that protects them. Mushrooms have little protection except
that once established they are fierce competitors. The most important tool
that the mushroom grower has is sanitation.
Even if the experienced individual needs help, discussing his needs
will do little help others. More discussion of wastes will be useful, but we
need to have a place to grow the mushrooms, or it will be difficult to do
much. So let us begin by discussing buildings. The buildings are the physical
protection for the mushrooms.
The reason most building looking for a use are a poor choice is because
they do not provide the things the mushrooms need. It should be apparent
that if most building are inadequate, mushrooms have special needs. How
will we learn their special needs? One of the very best ways to learn the
needs of living things is to observe the conditions where they grow normally.
THE NATURAL ECOLOGY OF MUSHROOMS
Oyster mushrooms are found wild in temperate forests and some species in
tropical forests (
Fig. 1). Typically, they grow on dead logs, one relatively
uncommon species attacks weak living trees. We would, therefore, expect
logs to be the best substrate, but we have found that straw and some other
ligno-cellulosic wastes are better for cultivation. Forests are generally moist
3
CHAP 1 FACILITIES
Fig. 1.
Oyster mushrooms (Pleurotus) in a natural, wild environment.
4
OYSTER MUSHROOM CULTIVATION
Fig. 2.
Agaricus growing in the wild - grass.
places with dim light. Logs are sometimes buried by other forest debris. The
survival of the species depends on the ability of mushrooms to protrude above
the surface. Oyster mushrooms have evolved to use low carbon dioxide
concentrations and light as indicators that they have reached above the surface.
However, the trees filter out much of the light and blue light predominates,
so mushrooms respond only to blue light. Many other wood inhabiting
mushrooms have very similar needs.
Relatives of the common commercial mushroom are found in more
open places and are associated with manure and already rotting debris (
Fig.
2
). While open places might suggest a need for light, we have found that
Agaricus
and other mushrooms associated with already rotting materials do
not use light, but depend primarily on gravity as a signal to grow away from.
5
CHAP 1 FACILITIES
Carbon dioxide is also avoided. Wind is more likely to remove carbon dioxide
in the open. Probably, it is also more likely to benefit from photosynthetic
removal of carbon dioxide by grass and other small plants.
We can not get all answers necessary to describe the environment,
simply from observations in the wild, but we can see that there are special
requirments for envionments that we should be prepare to deal with in our
buildings and in the other parts of our cultivation environment.
BUILDINGS AND OTHER FACILITIES
We have said that most ordinary buildings are not suitable for mushrooms.
Oyster mushrooms have some basic requirements for the environment
provided by the growing-buildings:
1.A temperature of 15 to 20°C (59 to 68°F)
2.A humidity of 80 to 95%
3.Good ventilation
4.Light
5.Sanitation
Temperature and humidity should be kept as constant as possible and the
exact needs may depend on the variety. Any rapid changes in temperature
will cause disastrous changes in humidity. At 20°C (68°F) and 90% humidity,
if the temperature drops to 19°C (66°F) the humidity rises to 100%. If the
temperature rises to 21°C (70°F) the humidity drops to 82%. At 15°C (59°F)
the change will be approximately 1% less. That is 99% for 1°C loss and
83% for 1°C increase. The relation between temperature and humidity make
insulation a must. Insulation may be a commercial material, but a thick layer
of soil over a masonry building or straw or even paper between the inner and
outer wall surfaces can be adequate.
At 100% humidity, everything is suddenly wet. Conversely, at 80%
humidity, the mushrooms begin drying. If everything becomes wet, then many
building materials will rot and others will corrode. So growing conditions
6
OYSTER MUSHROOM CULTIVATION
limit our choice of building materials. Concrete and plastic are two materials
that will withstand considerable moisture with little damage. Some growers
use wood or metal structures and cover them with plastic. Others just use
wood or metal and accept its very limited life. The biggest problem with
wood and some other porous materials is that they can harbor diseases and
pests.
Both a good vapor barrier like polyethylene and insulation are needed
to maintain temperature and humidity. In
Fig. 3 we see commercial insulation
in plastic between the ribs (rafters) of a metal building. In Asia they have
built houses of bamboo, polyethylene sheet and used straw for insulation
(
Fig. 4).
Good ventilation is needed for healthy mushrooms and for healthy
workers. Low carbon dioxide is required for mushrooms to form. The stems
of Pleurotus
as well as other wood inhabiting mushrooms will grow until the
carbon dioxide is very low. Centrifugal blowers are generally used to supply
air. The air should be heated or cooled first and then humidity added before
it enters the room. Of course, steam can humidify and heat at the same time.
Ventilation must remove the carbon dioxide formed by the mushrooms, people
and anything else. People can stand almost 10% carbon dioxide, but the
mushrooms are more sensitive. Mushrooms should be picked before spores
are shed, however, even with good management some spore will be released.
Spores can cause asthmatic and hay fever reactions, ventilation can help
reduce the spores in the air.
Light is required for oyster mushrooms and most other tree inhabiting
species. One may read many things about the amount of light, but there have
been very few carefully done experiments. I mentioned that forest light is
blue. I have tried and failed to produce mushrooms with incandescent light.
It is a rather yellow light. Fluorescent lights come in a variety of colors, The
most common are "cool white." With cool white if there is enough light to
read and they are lit 8 hours each day you will have enough light. Natural
daylight does not work well because the temperature will be affected by the
sun. Algae and other plants are more likely to cause trouble in daylight.
Agaricus
, the common commerial mushroom, does not require any
7
CHAP 1 FACILITIES
light and some of the older varieties change color with light. Generally the
only light in the houses are battery operated lights on workers’ helmets.
So, we generally do not want windows in any mushroom growing
buildings. If light is needed by the mushrooms, fluorescent lights are generally
the best light to use. If light is required only by people, battery operated
lights are ususally the most satisfactory.
Sanitation is the most important thing that must be provided by the
building. Sanitation will include:
1. Filtered air in
2. Screen or filters at air exits
3. "Air-lock" changing room
4. Foot bath
5. "Air tight"
Fig. 3.
Building
with insulation
covered by a
plastic vapor
barrier.
ALL openings should provide some means to keep out diseases and pests.
Air exits should have a fine mesh screen or a filter. Air inlets should be
filtered to keep out pests and diseases. A High Efficiency Particulate Air
(HEPA) filter is ideal, but other filters may be completely adequate.
Fig. 5
8
OYSTER MUSHROOM CULTIVATION
shows two excellent furnace/air conditioner filters. If no commercial filters
are available, three layer of muslin or similar fabric will be a good substitute.
Screens or filters should also keep insects out of the air exits. Power failures
and other problems may interrupt ventilation and insects will enter. They can
even fly against the flow of air if it is not fast.
Fig. 4.
Growing
buildings constructed
of
bamboo,
polyethylene
sheet
and straw.
Top
: Thailand
Bottom
: Taiwan
A room for workers to enter the growing facility can be built very
cheaply with a light framework and black plastic film. It can contain rubber
boots, a salt or hypochlorite foot bath and maybe clean clothes, masks or
rubber gloves. The poorest possible source of light for mushrooms is sodiumvapor
lamps. However,
they are extremely efficient
for outdoor lighting. While
they
are efficient
for people. Insects can not see with them, so they are also
9
CHAP 1 FACILITIES
Fig. 5.
Two high quality furnace/air conditioner filters.
good for "air-lock" changing rooms. Yellow colored incandescent light bulbs
are also available, and are adequarte for humans, but are not seen by insects.
If the building can be made air tight, except of the controlled air inlets
and exits, most diseases and insects can be kept out. Insulation foam, silicon
or other caulk can be used to close small openings.
SUBSTRATE INITIAL PREPARATION AREA
Agaricus
requires an area where substrate is wetted and ingredients mixed.
That area is almost always outdoors although often there is a roof with no
walls where front loaders and other machinery can do the heavy work. The
area should always have a concrete surface that can be decontaminated, if it
becomes a source of insects or disease.
Following mixing, the substrate must be composted. That may be done
in the open, usually with heavy machinery to turn it. However, men with
10
OYSTER MUSHROOM CULTIVATION
Fig. 6.
Right: A small hammer
mill (open) showing hammers
and "screen."
Below
: Straw that was chopped
by the hammer mill.
hayforks can do the job. Today most farms are using tunnels or "bunkers".
These are indoor facilities where air is blown up throught the substrate as it
ferments to compost. It is possible to add steam and pasteurize in the tunnels,
as well.
Wood inhabiting species
often use substrates which are more easily handled
if they are first chopped in a hammer mill. Usually the best substrates are
mixtures of several ingredients. The area should be dry, so a roof or more
protection will be desirable for chopping and mixing.
In some cases, the substrate will remain dry until pasteurization takes
place, in others it will be wetted before pasteurization. In still others it will
be wetted and placed in the growing container as part of the preparation.
No mater how the substrate is handled after preliminary preparation,
appropriate space must be available.
11
CHAP 1 FACILITIES
FINAL PREPARATION AREA
Pasturization
requires equipment that can assure that the temperature of
ALL
the wet substrate is 55° to 60°C (131º to 140ºF) for at least 30 minutes.
IT MUST NEVER BE AT A HIGHER TEMPERATURE!
It must also
provide conditions to protect the substrate from fresh contamination and
allow it to cool slowly so that it is about 25°C (77ºF) after 16 to 20 hours.
Sterilization
requires equipment that can assure that the temperature of ALL
the wet substrate reaches 121°C (250ºF) for about 15 minutes. A pressure
vessel is require to reach such temperatures. The substrate must be in
containers the exclude the entrances of all microorganisms. Cooling must be
slow enough so that there is little difference between atmospheric pressure
and the steam or water vapor in the container of substrate.
Sterilization requires much more expensive equipment, much more
fuel and much greater care at every step than pasteurization. It is almost
universally recommended for some species that bring high prices. A few
recommend it for
Pleurotus. However, that suggests that they do not know
proper pasteurization proceedure.
SPAWNING FACILITY
The place where the substrate is pasteurized, cooled, or sterilized must be
maintained with greater sanitation than the growing area. It will probably be
the best place to spawn as well. The air needs to be reasonable for those
working there. But air temperature and humidity need not be controlled
closely. It is ideal to have pasteurization or sterilization and spawning several
kilometers from the growing area. Such an arrangement avoids many sources
of disease and pests. The equipment at this facility is a substantial part of the
whole. However, it will be discussed under the process because there is a
choice of methods and equipment.
12
OYSTER MUSHROOM CULTIVATION
SUMMARY
Mushroom cultivation has many facilities requirements. There are no shortcuts
to those requirements. If the requirements are not met, failure, or at least
poor production is assured. The facilities must provide the environment
required for mushroom growth. The facilities must also provide the primary
protection against insects, other pests and disease. Without the environment
and protection provided by the facilities, management can not p
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