One of the first methods developed
for cultivating mushrooms was the cultivation of Shitake mushrooms
on logs — the first written record being that of Wu Sang
Kwang of the Sung Dynasty of China (960-1127 AD). The advantage
of log cultivation is the relative ease of the method and care
of the logs, and the life span of the fruiting logs (2-3+ yrs.).
The disadvantage is the unpredictability of the method (yield)
and the length of time between inoculation and fruiting (6-12 months).
Some mushroom species for which log cultivation techniques are
applicable include: Reishi or Ling Chi — Ganoderma
lucidum; Maitake
or Hen of the Woods — Grifola frondosa; Lion's
Mane — Hericium erinaceus; Shitake — Lentinula
edodes; Chicken of the Woods — Polyporus
(Laetiporus) sulphureus; Oyster Mushrooms — Pleurotus
sp.
Log cultivation involves the placement of "plug" spawn
into suitable logs. Plug spawn is most conveniently to be found
on fluted hardwood dowels. You can produce your own plug spawn
by weighing a quantity of dowels into a mason jar; adding an
equivalent weight of water; sterilizing as with grain spawn;
and inoculating the dowels with mycelium covered agar, grain,
or sawdust. If the logs to be inoculated are a different wood
than the dowels then 1or 2 grams of the log's wood should be
placed with the dowels. Sawdust spawn can also be use to inoculate
logs; a special tool called a "sawdust palm inoculator" can
be used to facilitate the process.
Hardwoods such as oak, cottonwood and elm are often recommended
as standard for log cultivation. Thick-barked hardwoods are preferred
over paper-bark woods such as birch. Maple and alder are also
frequently seen in the literature. Plum wood is given mention
in the cultivation of Reishi Mushrooms. Logs should be cut to
lengths of 3-4 feet, three weeks to three months prior to inoculation
(plugging). Stumps can also be used. The period of time between
cutting the logs and inoculation allows the naturally released
anti-fungal (wound compounds) terpenes and (poly) phenols to
degrade so that they do not inhibit the colonization of the log
by the mushroom mycelium. Logs and stumps can be inoculated any
time between last and first frost. Holes, 2 inches deep, of the
same diameter as the plugs being used are drilled into the logs,
2-4 inches apart. Stumps are inoculated around their circumference
into the sapwood (between the bark and the heartwood). One mycelium-covered
dowel per hole is then pounded into each hole in the log or stump.
Holes can be painted with cheese wax or beeswax to protect the
mycelium during incubation. The ends of the logs can also be
painted with wax if moisture retention is a concern. (Note: in
higher temperature climates, such as our own, the wax can melt
into the dowel holes and potentially cut off the availability
of air to the mycelium. Thus, there is a toss up between the
advantages of moisture retention/mycelium protection vs. adequate
aeration of the developing mycelium.) After the logs are plugged,
they are stacked in a suitable location in crisscross piles called "ricks" for
incubation over the next 6-12 months. The rick stacking helps
to maintain an even moisture content/environment. The logs can
also be covered with tarp (not with plastic) to help conserve
moisture. Beds of (and insulation with) sawdust and/or wood chips
is a very effective and simple method of environmental control.
During incubation, logs should be watered once or perhaps twice
a week as required to maintain an optimum humidity.
After 6-12 months of incubation, the logs are checked for mycelia
growth by chipping away an area of bark around one of the plugs.
If mycelia growth is evident fruiting is initiated by soaking
the logs by submerging them in a tub or tank (or watering with
a sprinkler) for 24 hours. Chlorinated water should be avoided
for fruit initiation although it is acceptable for general watering
of your logs. The logs are restacked in an arrangement that allows
fruiting from and access to all sides of the logs. Watering is
continued 2-3 times a day (2-3 times a week for partially buried
logs and stumps) or as required- depending upon the prevailing
weather conditions. Mushrooms should begin to form two weeks
after initiation. After each flush, allow the logs 2-3 week dormancy
period before reinitiating fruiting. This cycle of fruiting and
rest can be continued throughout the growing season. Some hardwood
logs have been reported to bear fruit for upwards of 3 or more
years although the size of the crop decreases each season. |
