ГЛАВА 3

Р?НОКУЛЯЦР?РЇ Р? РљРћР›РћРќР?Р—РђР¦Р?РЇ БЕДНЫХ СУБСТРАТОВ

(Перевод CHAPTER VII SPAWNING AND SPAWN RUNNING IN BULK SUBSTRATES РёР· РєРЅРёРіРё СћСћPaulStamets ==Пола СтаметсаЇЇ “The Mushroom Cultivator”)

РЋРЋToCРЋРЋ

The inoculation of compost or bulk substrates is called spawning. The colonization of these
substrates by the mushroom mycelium is known as spawn running. At spawning and during
spawn running there are several factors that must be considered if yields are to be maximized. These
factors are:
1. Moisture content of the substrate.
2. Temperature of the substrate.
3. Dry weight of the substrate per square foot of cropping surface.
4. Duration of spawn running.

Moisture Content

Mushroom mycelium does not grow in a substrate that is either too dry or too wet. A dry substrate
produces a fine wispy mycelial growth and poor mushroom formation because the water essential
for the transport and assimilation of nutrients is lacking. On the other hand, an over-wet substrate
inhibits mycelial growth and produces overly stringy mycelia. Controlled experiments with
Agaricus brunnescens grown on horse manure composts have shown yield depressions when the
moisture content deviates more than 2% from the optimum. Deviations greater than 5% generally
result in a spawn run that does not support fruitbody production. A dry compost at spawning should
be lightly watered and mixed well to guard against the formation of wet spots. For an over-wet compost
the common procedure is to add gypsum unti! the loose water is bound.

Substrate Temperature

Since mushroom mycelium grows within the substrate, the substrate temperature must be
monitored closely. Thermometers are placed both in the center of the substrate—the hottest region
—and in the room's atmosphere. These two thermometers establish a temperature differential. If the
hottest point in the substrate is 80 В° F. and the air is 70 В° F. then the temperature of the total mass
must lie within this range.

The optimum temperature for mycelial growth varies depending on the mushroom species.
Agaricus brunnescens grows fastest at 77 В°F. whereas Psilocybe cubensis prefers 86 В°F. Temperatures
higher or lower simply slow mycelial growth. The growth curve shown in Figure 119 illustrates
the effect of temperature on the growth of Agaricus brunnescens mycelium. Note that growth
slows at a faster rate as the temperature rises above the optimum. Therefore the object during spawn
running is to keep the substrate within the temperature range that is optimal for the fastest growth of
mycelium.

Dry Weight of Substrate

Other factors aside, the dry weight of substrate per square foot of cropping surface largely determines
total yield. Commercial Agaricus growers aim for at least five pounds of dry weight of compost
per square foot and sometimes compress up to eight pounds per sq. ft. into their containers.
Cropping efficiencies are calculated by dividing total yield per square foot into the dry weight of one
square foot of the substrate. Thus a yield of four pounds per sq. ft. of freshly picked mushrooms divided
by five pounds dry weight of substrate equals an 80% cropping efficiency. Efficiencies of
80–100% are considered to be close to the maximum yield potential of Agahcus brunnescens.

The actua amount of substrate that can be compacted into one square foot of growing area and
managed depends upon the cooling capabilities of the control system as well as the outside temperature.
Experiments using Tracer elements in mushroom beds three feet deep have shown that nutrients
from the farthest point are transported to The growing mushrooms. Yields per sq. ft. increased
although at a lower substrate efficiency.

During spawn running the metabolism of the growing mycelium generates tremendous quantities
of heat. Substrate temperatures normally reach a peak on the 7th-9th days after spawning and
can easily reach 90 В°F. At this temperature thermophilic microorganisms become active, thereby increasing
the possibilities of further heat generation. The substrate can easily soar above 100 В°F, and
a compost can actually rise again to conditioning temperatures. Temperatures between 95–110В°F.
can kill The mycelium of many mushrooms. Even if the mycelium is not completely killed, these
temperatures do irreversible harm to mycelial vitality and fruiting potential. These elevated temperatures
also stimulate the activity of competitor molds and may render the substrate unsuitable for further
mushroom growth. Because of the enhanced heat generating capabilities of deeply filled beds.
Agaricus growers rarely fill more than 1 2 inches of compost into the beds.

The decision on how deep to fill the spawned substrate is an important one. Here again, the
ratio of substrate to free air space in the growing room is significant. (See Chapter IV). An efficient
method of spawn running is to The fill trays 6–8 inches deep with compost and stack them closely together
in the room. In this manner the heat generated within each tray remains controllable, while at
the same time the total compost heat will be sufficient to heat The room. Outside air temperature as
well as the capacity of the heating and cooling equipment should determine how many substrate
filled containers can be placed within a given space. Fresh air is generally used to provide cooling
except when it is warmer than the room temperature.

Duration of Spawn Run

Once colonization is complete, the substrate should be cased, or if casing is not used, it should
be switched to a fruiting mode. If spawn running is continued beyond this point, valuable nutrients
that could be utilized for production of fruitbodies will be consumed by further vegetative growth. If
for some reason the cropping cycle must be delayed, the substrate should be cooled until a more
opportune time.

Spawning Methods

Spawning methods, like spawn itself, have evolved over the years. As late as 1 950 Agaricus
brunnescens growers customarily planted walnut sized pieces of manure spawn or kernels of grain
spawn in holes poked into the compost at regular intervals. Using this method spawn running was
slow, and areas far from the inoculum were more susceptible to invasion by competitors. The full
potential of grain spawn was not realized until the development of “mixed spawning”. The principle
of mixed spawning is the complete and thorough mixing of the grain kernels throughout the substrate.
In this manner all parts of the substrate are equally inoculated, resulting in the most rapid and
complete colonization possible.

The standard spawning rate used by Agaricus growers is seven liters/Ton of compost or one
quart/8 sq. ft. If spawn is readily available and cheap, it is advantageous to use high spawning rates
which lead to more rapid colonization. It is also advantageous to break up the grain spawn into individual
kernels the day before spawning. If the spawn is fresh, the grain should break apart easily. If
the spawn can not be used when fresh, it should be refrigerated at 38В°F.

The basic principle of spawn running is the same regardless of the type of mushroom or substrate.
COLONIZATION MUST PROCEED AS RAPIDLY AS POSSIBLE TO PREVENT
OTHER ORGANISMS FROM BECOMING ESTABLISHED. Once the mushroom mycelium becomes
dominant, natural antibiotics secreted into the substrate inhibit competitors. To prevent invasion
by competitors it is important that spawning take place under carefully controlled hygienic conditions.
Fungus gnats in particular must be excluded, and for this purpose a tight, well sealed working
area is best. This area and all tools should be disinfected one day prior to spawning with a 10%
bleach solution. When using disinfectants be sure your skin is protected and avoid breathing any
fumes.

If the substrate has been filled into shelves, the spawn is broadcast over the surface and mixed in
with a pitchfork or by hand. With trays, a similar method can be used, or alternatively, the substrate
can be dumped out on a clean surface, mixed with spawn and then replaced in the trays. Substrates
from a bulk room are removed, mixed with spawn and then placed into the chosen container.

It is common procedure to level and compress the substrate to avoid dehydration caused by excessive
air penetration. The degree of compression depends upon substrate structure. Long, airy
materials can be compacted more than short, dense ones. Commercial tray growers compact the
compost into the trays with a hydraulic press so that the compost surface resembles a table top. This
enables the application of an even casing layer.

Environmental Conditions

The required environmental conditions for spawn running are very specific and must be closely
monitored. Substrate temperatures are controlled by careful manipulation of the surrounding air
temperature. Heating and cooling equipment are helpful but not absolutely essential unless the outside
climate is extreme. A well insulated room with provisions for fresh air entrance and exhaust air
exit should be adequate for most situations. The steady or periodic recirculation of room air by
means of a small fan helps to keep an even temperature throughout the room and guards against localized
over-heating, especially in the uppermost containers. Humidity is extremely important at this
time and must be held at 90–100%. If the humidity falls below this level, water evaporates from the
Jbstrate surface to the detriment of the growing mycelium. Humidification can be accomplished by
steam humidifiers or by cold water misters. If steam is used, care must be taken that the increase in
r temperature does not drive the substrate temperature above the optimal range. One common
method of counteracting drying is to cover the substrate with plastic. Be ready to remove the covering
during the period of peak activity if temperatures rise too quickly.

During spawn run the mushroom mycelium generates large quantities of carbon dioxide. In
fact, it has been demonstrated that mushroom mycelium is capable of C02 fixation. Because of this
ability to absorb CO2. room concentrations of 10,000–15,000 ppm are considered beneficial and
desirable. A C02 level high enough to stop growth is uncommon under normal circumstances. Being
heavier than air, C02 settles at the bottom of the room, which is yet another reason for even air
circulation within the growing environment.

Super Spawning

Super spawning is also called “active mycelium spawning” vis a vis the Hunke-Till process.
Essentially, a set amount of substrate is inoculated and colonized in the normal manner. The fully
run substrate is then used as inoculum to spawn increased amounts of a similar substrate. One
could theoretically pyramid a small quantity of inoculum into a considerable amount of fully colonized
substrate. This technique requires the primary substrate to be contaminant free; otherwise
contamination, not mycelium, will be propagated. The possibilities inherent in this method may be
of greater application when transferring naturally occurring mycelial colonies to non-sterile yet
mushroom specific substrates. An excellent example of this is the propagation of Psilocybe
cyanescens on wood chips. (See Chapter VI.)

Supplementation at Spawning

One of the newest advances in Agaricus culture is the development of delayed release nutrients
added to The compost at spawning. These supplements are specially formulated nutrients encapsulated
in a denatured protein coat. They are designed to become available to the growing mushrooms
during the first three flushes. The application rate is 5–7% of the dry weight of the substrate.
Yield increases of '/2 to 1 Ib/sq. ft. are normal. Here again, complete and thorough mixing is essential
to success. Caution: these materials enrich the substrate, making it more suitable to contaminants
if factors predisposing to their growth are present. (For suppliers of delayed release nutrients,
refer To the resource section in the Appendix).

Supplementation at Casing (S.A.C.)

SACing is another method used to boost the nutritional content of the substrate. The materials
used are soy bean meal, cottonseed meal, and/or ground rye, wheat or kafir corn grains. The fully
colonized substrate is thoroughly mixed with any one of these materials at a rate of 1070 of the dry
weight of the substrate. The substrate and the supplements must both be clean and free from contaminants;
otherwise contamination will spread and threaten the entire culture. High substrate temperatures
should be anticipated on the second to third day after supplementation. With this type of
nutrient enhancement yield increases of '/2–2 Ibs/sq. ft. are possible.