It is known as
"shiitake" in Japan. Origin of this mushroom is China. The shiitake mushroom
grows on old wood from dead residues of trees. Various hardwood species of trees have been
used in the bed log production of shitake.
Paddy Straw Mushroom
The paddy straw
mushroom is the most popular Southeast Asia. Several species of Volvariella have been grown for food V. bombycina (Schaellff. Ex.Fr.) Sing. And V. diplasia (Berk. & Br.) Sing. have been
cultivated in India. V. diplasia is white V.Volvacea is blackish V. bombycina differs from the cultivated V.volvacea in terms of habitat as well as colour.
Volvariella volvacea thrives in a temperature
range of 28 to 360C and relative
humidity of 75-85%. This mushroom can be grown by various methods.
A good substrate
should provide good anchorage, good aeration and have the right water holding capacity and
also contain the necessary nutrients, released from the raw compost materials during
fermentation. After these two stages of fermentation, the compost becomes a selective
substrate. When the mushroom spawn is planted, it can spread throughout the compost in
short time with little competition. Volvariella mycelium
grows both on composed and non-composted substrates.
Substrate Preparation and Spawning:
(Nonpasteurized) Portable Outdoor or Indoor Beds: -
Production of Volvariella
mushroom in open portable wooden boxes provides for the easier management of pests and
diseases. Materials needed are wooden boxes, paddy straw/banana leaves and plastic
sheets/growing houses. The frames are 60 x 45 x 20 cm size, open on all sides.
materials are cut to a uniform length of 20 cm. The boxes are filled with the bedding
materials, lightly packed in parallel rows. The bedding materials may be bundled to
facilitate the filling of the boxes. The packed materials loosen when soaked in water so
the initial packing should be as tight as possible. The boxes of bedding materials are
soaked in water for at least 3 hours. With proper soaking, the straw becomes dark brown
and the banana leaves become more transparent. The boxes are removed from the soaking area
and excess water is drained away. The soaked substrate is spawned by inserting pieces of
spawn along the edges of the packed substrates.
substrate in the boxes may be placed in a specially built incubation room with a high
temperature (35 to 380C) and high
relative humidity (at least 5%), or it may be covered with plastic sheets and placed under
shade outdoors. A good spawn run takes about 5 to 7 days. Subsequently, small pinheads
begin to form along the open edges of the boxes.
Nonpasteurized Outdoor Beds by Bundles: -
bundled paddy straw is soaked in water overnight and piled into heaps of three or four
layers, with spawn broadcast between the layers. The heap is compacted until it is 30 to
60 cm thick. Thickness varies according to growing season: during warm weather, the height
of the bed should not exceed 50 cm so that the bed will not overheat and kill the spawn.
The latter method has the advantage of raising the temperature of the heap. Each bed is
covered with paddy straw or plastic sheet for humidity control. Use of newly harvested but
dried straw, high quality spawn and good cultural management of the bed to avoid pests and
diseases are important considerations for obtaining higher yields.
Indoor or Outdoor Molded Beds: -
In this method wooden frames of
various sizes are used. The usual size is 30 cm wide and 30 cm high and the length
of the frame varies according to the amount of substrate available. The frame is open at
the top and bottom. A growing house made of used to control humidity and heat, and to
protect the beds from sunlight. Materials used are simple and include: (i) Chopped paddy
straw (ii) Cotton waste (iii) Wooden frame 30x30x50 cm (iv) Water for soaking straw and
cotton and (v) Growing house or a dark room.
The straw and the
cotton waste are soaked separately. The soaked straw, after complete draining, is placed
in the wooden frame on a wooden platform and compacted by trampling. The soaked cotton
waste is spread around the edge of the wooden frame in a strip about 8 to 10 cm wide.
Spawn is broadcasted on the cotton. More soaked straw is packed into the wooden frame, and
trampled as before. The process is repeated three times, spreading cotton waste over the
top layer each time.
The wooden frame is removed and the
prepared small beds are carried to a growing house on the wooden platform. The temperature
should be about 32 to 350C. The
moisture content of the beds is checked daily. The beds must not become soggy and
anaerobic. Prepared beds may be established outdoors where there are covered with plastic
sheets. Mushroom appear in 5 days and are ready for harvest in 7 days.
A semi-industrialized method
production, which requires pasteurization of the growing substrate directly inside the
mushroom houses, requires indoor beds. Materials used in indoor cultivation are : Cotton
waste or chopped paddy straw, wooden frames about 92 cm x 28 cm (for composting) (sides
only-no top or bottom), Water, CaCO3 (calcium carbonate) 2% w/w of substrate
rice bran, and supplements : chicken manure (5% w/w) or sewage sludge (5% to 10% w/w) or
NPK chemical fertilizer (1% w/w). For preparation of compost, a wooden frame is placed on
the ground and the cotton waste or paddy straw raw materials are packed inside. Limestone,
fertilizer, and water are mixed with the material as it is packed. The materials are
tramped as they are added, to help with mixing and absorption of the water. When the frame
has been completely filled, it is pulled up to a height of about 15 to 20 cm and another
layer of compost is added in top of the first layer. A finished pile of compost usually
consists of four to six layers and is about 70 to 90 cm in height.
is covered with a plastic sheet and allowed to ferment. After two days, the fermented
compost is turned by hand or thoroughly mixed by a mechanical mixer. The rice bran (2% of
the dry weight of the compost) is added at this point. Water is also added, if necessary.
The mixed compost is re-piled and covered with the plastic sheet. Fermentation continues
for another two days.
A suitable size of
bed is about 0.4 m2. The layer of
compost should be about 10 cm thick and should consist of about 8 kg (dry weight) or 26 to
28 kg (wet weight) of compost materials. Live steam (pressurized and over 1000C)
is introduced into the mushroom house for Pasteurization. The air temperature about 60 to
600C is maintained for another 2 hours. The temperature is then gradually
lowered to about 520C by a gentle stream of fresh air. The temperature during
the next 8 hours is maintained at 50 to 520C
by a continuous fresh air supply. The steam valves are then closed and the
temperature is allowed to drop gradually to 34 to 360C . This can take 12 to 16
hours, depending on the outside temperature. The beds now become ready for spawning.
For Spawning, the air temperature is
cooled to 350C and the bed temperature to about 36 to 380C. The
amount of spawn to be used is calculated at 1.4% (dry weight) or 0.4% (wet weight) of the
compost. Pure culture spawn is removed from the bottles and placed on a tray for easy
handling. The spawn is broken into pieces about the size of peanuts. The pieces are
inserted into holes in the compost at a depth of about 2 to 2.5 cm spaced 12 to 15 cm
apart. The spawn is covered with the displaced compost and the beds are covered with a
plastic sheet. The temperature of the mushroom house is maintained at 32 to 340C
during the spawn running period. Full growth may take only 3 to 4 days, depending on the
compost quality and the temperature.
3-day period of spawn run, no water or light is needed. Only a limited amount of fresh air
is required during this period. Three days later fluorescence light and additional
ventilation are provided. On fifth day after spawning, mushroom primordia usually appear
on the surface of the beds. Four to five days later, the first flush of mushroom is ready
The first crop of mushroom is
usually harvested 10 days after planting the spawn. The first flush normally provides
three or four successive days of harvesting and produces 85 to 90 % of the expected yield.
During the next 3 to 5 days (the rest period), additional water may be added to the
substrate. Stable conditions must be maintained in the growing room during the period.
Spraying with superfine mist will maintain the desired humidity in the growing rooms and
protect the substrate form excessive drying. The temperature can be maintained at the
appropriate level by opening or closing the ventilators. The second flush may be also
provide 2 or 3 days of harvesting, but the yield is lower (10 to 15%of the total yield).
Volvariella is best harvested at the button (egg-shaped) stage when the volva or the
universal veil has not broken. A yield for outdoor beds ranges form 10 to 12% B.E. while
indoor beds of cotton waste may yield as high as 50% B.E.