GROWING GOURMET - Anto2ni.it

MATERIALS FOR FORMULATING A FRUITING SUBSTRATE 49
rooms growing from this source. (Arora, 1990.)
Cedars and redwoods are likewise not recommended
as they decompose slowly due to their
anti-rotting compounds. Obviously, these same
compounds stifle the growth of mushroom
mycelium.
Other woods than those listed may prove to be
satisfactory. Hence, experimentation is strongly
encouraged. I find that the fast-growing, rapidly decomposing
hardwoods are generally the best
because they have greater ratios of starch-enriched
sapwood to heartwood. These sugars
encourage rapid initial growth, resulting in full
colonization in a short period of time. The key to
successful cultivation is to match the skills of the
cultivator with the right strain on the proper substrate
under ideal environmental conditions.
For outdoor log culture, disease-free logs
should be selected from the forest in the winter
or early spring. If you use sawdust and chips
for indoor or outdoor cultivation, freshness
counts—or else competitors may have already
taken hold. Lumber mills, pulp mills, furniture
manufacturers, and many other wood productcompanies
generate waste usable to the mushroom
cultivator. However, those industries
which run mixed woods and do not separate
their sawdust into identifiable piles, are not recommended
as substrate suppliers. Cultivators
face enough problems in their struggle to understand
the different yields of each crop cycle.
Hence, mixed wood sources are best avoided,
if possible.
Red alder (Alnus rubra) is a "weed tree" in
western Washington State of North America.
Like poplars and cottonwoods, its penchant for
valleys, wetlands and open habitats encourages
a prodigious growth rate. Many of these trees
are common along roads where they foul telephone
and electrical lines.A whole industry has
arisen dedicated to rendering these trees into
chips, a fortuitous situation for mushroom cultivators
.A matrix of smaller and larger particles
can be combined to create an ideal habitat for
mycelium. The smaller particles stimulate
quick growth ("leap-off'). The larger particles
encourage the mycelium to form thick, cordlike
strands, called rhizomorphs, which
forcibly penetrate through and between the
cells.The larger chips become nutritional bases,
fruiting platforms, giving rise to super-large
mushrooms. This concept has been an overriding
influence, steering my methods, and has
resulted, for instance, in the large 5 lb. specimens
of Stropharia rugoso-annulata, the
Garden Giant, that is pictured in this book. A
simple 50:50 mixture (by volume) of sawdust
and chips, of varying particle sizes, provides the
best structure for the mushroom habitat. The
substrate matrix concept will be explored in
greater detail later on.
Cultivators should avoid wood chips originating
from trees along busy roadways.
Automobile exhaust and leachate from the oilbased
asphalt contaminate the surrounding soil
with toxins, including lead and aluminum. Metals
can be concentrated by the mushroom
mycelium and transferred to the mushrooms.
Wood chips from county roads with little traffic
are less prone to this heavy metal
contamination.This problem is largely circumvented
by obtaining sawdust and chips from
larger diameter trees. Sawmills and pulp chip
companies provide the cleanest source of wood
debris for substrate preparation.
Currently, the heavy metal concentrations
taken up by mushrooms are well below the standards
set by the United States government for
fish, for instance. However, air pollution is a
growing concern. My analyses of mushrooms
grown in China, California, and Washington
state revealed that the Chinese mushrooms had
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