GROWING GOURMET - Anto2ni.it

274 GROWTH PARAMETERS
Early formation of Shiitake has disadvantages. If the network of mycelium is insufficiently
formed, lacking both density and tenacity, high quality mushrooms can not be supported. If allowed
two weeks of colonization, top grade Shiitake is produced.
When the first crop is picked from the white blocks, they must be carefully cut flush with the outer
surface with a sharp knife or chunks of the sawdust substrate will be pulled off. I prefer to hold back
the fruitings until 28-35 days after inoculation, allowing less than a dozen mushrooms on the first
flush, and then exposing the substrate to the conditions recommended for crop development.
The first flush from white
blocks is unique and calls for a strategy totally different than for subsequent
flushes. Timing is critical. If one is not attentive, the window of opportunity can pass. During
incubation, the outer surface of
the myceliated sawdust appears as a smooth flat plane, pressed flush
to the surface walls of the polypropylene bags. After waiting 20-25 days until the blocks start "buckling"—an
irregular, blister-like surface topography
forms.* These formations are the precursors to
primordia. (See Figure 240). Several days after this surface topography forms, temperatures are
dropped and small brown spots form at the peaks of the blisters. Often appressing against the interior
plastic walls, the primordia can form overnight, measuring 1-3 mm. in diameter. Should more than a
dozen mushrooms form, or if develop underneath the plastic, the crop quality greatly suffers. The cultivator
must assess the maturity of the primordia population and expose the sensitive mycelium to the
air precisely at the right time by stripping the plastic bags from the blocks.
The mycelium is suddenly thrust into the highly aerobic environment of the growing room. Massive
evaporation begins from the newly exposed aerial, fluffy white mycelium. For this first flush,
which forms topically on the outer surface of the sawdust block, the humidity must be maintained at
100% under fog-like conditions until the desired number of primordia form. At this stage, the
Shiitake blocks are snow-white in color and dotted with several brown headed primordia. (See Figure
241).The sudden shift from the CO2 rich environment within the bag to the highly aerobic environment
of the growing room signals the block to bear fruit.
Since these events occur rapidly and the window of opportunity is so narrow, all the skills of the
cultivator come into play. Allowing too many primordia to form is a real problem. The more mushrooms
that are set, the smaller they will be, increasing the labor at harvest. The fewer mushrooms set,
generally the larger they will become. Despite the number of mushrooms that form, the yield remains
constant. The first flush from a moist 6 lb. alder sawdustlchip/brafl is usually 3/4 to 1 lb. of mushrooms
per block.
Once six to a dozen mushrooms form, relative humidity is lowered, and air turbulence is increased
to affect greater evaporation. The aerial mycelium collapses, or in mushroom lingo "pans". This flattened
mycelium becomes the thickened coat of dead cells, eventually giving rise to the brown skin so
characteristic of the remainder of the block's lifespan. (See Figures 246-247).
After the first flush, the fruiting blocks must dry out. The humidity in the growing room is lowered
to 30-50% and maintained around 70° F.(21° C.).** After 7-10 days of dormancy, the now browning
blocks weigh only 3-4 lbs. of their original weight. The blocks are submerged in water (non-chlori-
* Some cullivators call this "blistering" or "popcorfliflg".
** This fmiting strategy is specific to warm weather strains of Shiitake.
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