faced with the challenges of growing mushrooms, it can be helpful to
look at natural habitat of the mushroom species to figure out what
condition might be adversely effecting them. Simple observations of
the natural world can be a powerful tool to understand what might be
helpful in optimizing your growing parameters. Whether you are a
professional grower or passionate hobbyist, it gives you a chance to
geek out and really get down and know the élan
vital of your mushrooms.
use Pleurotis sp. Oyster mushrooms as an example:
all oyster mushrooms grow on logs, on or near to the the forest
floor, with plenty of fresh air.
often fruit after a precipitation event or a rapid change in
thrive in the low light conditions of the forest under normal
diurnal light and temperature patterns.
mushrooms grow all over the world, so as a genus they can live in a
wide range of conditions but many have spectated to live in an
narrow range of temperature and humidity conditions.
often grow on logs that host other fungi, mostly hardwood trees, but
most fungi they don’t live on cow paddies or other animal
waste, just the humus and dead trees of the forest.
are one of the ways fungi have evolved to spread their spores.
can we learn from all this?
Oyster mushrooms need Carbon, Hydrogen, and Oxygen to sustain their
life. In a mushroom log, these come in the form of cellulose,
hemicellulose and a little bit of lignin. There is some protein and
nitrogen present in the cells of a tree, but not a lot. Oysters don
not need much fertilization to thrive and fruit. Adding fertilizers
like nitrogen can help boost production but it is important to
remember these are NOT plants. They respond best to small amounts of
supplements in natural forms that they can break down like coffee
grounds, grain or hair. In some situations fertilizers can be a
detriment, because they attract and feed other fungi, bacteria, and
On the forest floor, oyster mycelium can live happily and not be
affected by a multitude of pathogens lurking in the soil. When
mushroom mycelium is healthy, it can keep invaders at bay. Always
take steps to insure mycelium can have a strong, fast run by
observing optimal temperatures and humidity with plenty of fresh air.
A fast run is your best defense against invading fungi or bacteria.
Mushrooms need fresh air, so you cannot shut them up in a room where
they are breathing their own waste products (CO2)
and expect them to do well. Mushrooms can fruit in a closed
environment, but expect them to be small and thin.
plastic bags to grow mushrooms is an efficient, cost effective way to
grow mushrooms. Really there is no other containment system besides
logs that works better. Obviously, they aren’t the ideal system as
far as air exchange. The humidity tents included in our grow kits have plenty of air holes, and we suggest maintaining good ventilation
in the room or area where the mushrooms are fruiting.
Like plant flowering, mushroom fruiting is actually a stress
response. It is a last ditch effort to have genes survive in the
form of spores under adverse conditions. Things that stress the
mycelium enough to form fruits include: rapid change in temperature,
an increase in moisture, a physical trauma (like dropping a log on
the ground), or coming to the end of its food source (a bag or log
full of mycelium).
easiest way to induce fruiting is by imitating a natural rain event.
Finding a happy medium for everyday growing with moisture and
mushrooms can be a bit of a challenge. I recommend keeping the
moisture low. After all, in nature you will have times when mycelium
will survive during very low moisture conditions. When things are
too wet it invites all kinds of invaders. Keeping the moisture and
humidity low also allows for a big rain-like signal that will induce
fruiting when you do add water. When you are ready for a flush get
out the hose or, in the case of logs, soak in a bucket for 24 hours.
Mushrooms grow outside where
there is plenty of light. They often stay on the shady side of the
log or in a crevices. For fruiting it is necessary to expose mycelium
to some light but keep it out of direct sunlight. They can take only
small amounts of direct sunshine. If they are indoors in a room that
has windows, use a light to mimic the natural day and night cycle.
Many people are surprised to find out things like mushrooms and
bacteria can tell time. The fact is for the whole evolution of life
on our planet there have been regular light and dark cycles. Given
the Earth’s volatile beginnings, it is pretty much the only
environmental constant that early lifeforms could count on.
mushroom mycelium can be grown in the deep regions of a dark log so
you can keep mushrooms in the dark during a spawn run. However, to
initiate fruiting you will need normal light and dark cycles. If you
are growing the mushrooms indoors without windows you will need a
timer or manually turn lights on and off. Also, having the
temperature lowered about 10°F
at night will mimic normal temperature swings and get the mushrooms
in the mood to fruit.
Blue and Pearl oysters are warm and cold weather varieties,
respectively, but tend to be flexible with the range of temperatures
in which they fruit. As with high CO2
levels, if oysters are grown outside optimal temperatures, expect
flushes to be weaker and fruits to be smaller. Pictured here are
Pearls and Blues that got too cold.
a particular oyster strain doesn’t do well for you in any given
season, try another. The strain you are using might have evolved to
a point where they can’t be made happy with their environment. There
is almost always a strain that will work for the temperatures, light,
growing medium and humidity you can easily provide.
of our expert customers and farmers have developed a yearly cycle for
what type of mushrooms they produce. Sometimes the spawn they order
is exactly what you would expect- winter tree, pearl, and elm oyster
for winter, pinks for summer, etc. Sometimes it is counter to what is
read in many mushroom growing reference books. Many grow elms in the
summer and blues in the winter. Mix it up and try a different strain
or even species if you are having trouble growing in a particular
Oyster mushrooms grow fast and breakdown and eat the cellulose,
hemicellulose, and a little bit of lignin. Other fungi, like
woodear, are better at breaking down the fortified lignin walls
allowing the fast-growing oysters to move in and enjoy the rest. So
plant waste and materials made from plant cellulose that have little
or no lignin (straw, paper, jute, agriculture wastes) are great for
growing Oysters on logs, use young trees that have more light colored
sapwood than the sturdy lignin fortified darker heartwood. “Softer
Maple, Poplar, Beech, Birch, Elm, work best for oysters.
Conifers contain resins that pine trees have evolved to fend off
fungal and other invaders (think turpentine or cedar chips). Once
these strong smelling compounds are gone fungi, like oysters, move in
and have a feast on the nice soft pine wood.
that can grow on pine logs like Phoenix, only grow on less aromatic
species like fir and hemlock. If you are using sawdust to grow
oysters it is best to avoid all evergreens, especially cedar. Just a
little bit of pine sawdust can inhibit oyster growth completely.
The myth that all mushrooms like to grow on horse pucky in basements
is a notion we try to dispel here at EM. Almost all of the mushrooms
we grow here live in the woods and grow on logs or from organic
matter on the ground.
Like flower pollen and fruit seeds, mushrooms are a fungus’s way of
spreading their spores/genes around. Like seeds and pollen,
mushrooms and spores can attract the animals and insects. Some
mushrooms even glow in the dark to attract insects – like moths to a
flame. If you are growing outside, anticipate that you might have
some bug visitors. Take proactive measures to try to limit their
access. Simple things like harvesting mushrooms as soon as they are
ready will go a long way to keep a population from moving in and
making a home.
many mushroom growers, my background is in plants. While a knowledge
of growing plants is very helpful, fungi do grow very differently.
If you are new to growing mushrooms take a moment to appreciate the
time line of fungus growth. The mycelium run can take as long as a
month in bags to several months on logs. Then fruits can appear
suddenly. It takes some time to get accustomed to the idiosyncrasies
of growing mushrooms. Much like growing plants, the more you
appreciate, observe and understand the needs of the mushroom the
better grower you will be. A green thumb can turn into a beige
thumb in no time!