|Mushroom Cultivation in Thailand (Peace Corps, 1987, 85 p.)|
|4. Straw mushroom cultivation in beds|
Straw mushrooms are most commonly cultivated in beds in Thailand. Angel and oyster mushrooms are also grown in beds, but much less often.
The materials needed to cultivate straw mushrooms in beds are the following:
1. Rice straw, or dried water hyacinth as the growing substrate. (Note: With rice straw, use the bottom portion of the stalk left in the fields after harvest. The bottom portion is preferred because it absorbs and retains water better than the upper portion harvested with rice grain and offers a more humid atmosphere for mushroom growth than the tops of the stalk which dry rapidly.) Other substances that may be used include: banana tree trunks and leaves, maize residues, mung bean husks and para rubber tree pulp.
2. Supplementary food made from dry chicken, pig, cattle or buffalo manure mixed in a 1:1 ratio (by volume) with chopped or shredded dry water hyacinth or rice straw. The mix should be watered until thoroughly moistened. Cotton and/or kapok may also be added to the mixture.
3. Spawn. Choose spawn that is sweet smelling and healthy looking with long white mycelium threads visible throughout the growing substrate. (Note: For more information concerning the purchase and handling of mushroom spawn refer to Appendix F.)
4. Watering can and water. Be careful not to use chlorinated water, as it will kill the mushroom spawn. If only chlorinated water is available, it can be dechlorinated by collecting it in a jar and allowing the water to sit for two days. The chlorine dissipates and the water is acceptable for use.
Use of the wooden mold
5. Wooden mold, approximately 80-120 cm long, 40 cm wide at the base, 35 cm wide at the top (to ease removal of the wooden mold once the bed has been constructed).
Figure 18: Wooden Mold
6. Clear plastic sheet and rice straw to be used to cover the beds.
The steps required in the cultivation of straw mushrooms are as follows:
1. Soak the rice straw or dried water hyacinth overnight in water for best results during the cold and hot seasons. During the rainy season, it is possible to soak the straw for only 15-20 minutes and achieve good results, although a longer soaking period is preferable.
Figure 19: Soaking Rice Straw
2. Prepare the soil where the beds are to be made by spading an area approximately 120 cm wide 6-8 cm deep and 7 meters long. Expose this area to the sun for 3-4 days in order to kill any existing bacteria and/or fungi. During the rainy season construct a raised bed 5-10 cm above the surrounding soil level to prevent flood damage during heavy rains.
3. Place the wooden mold at one end of the prepared soil area and sprinkle the supplementary food around the inside border of the mold, creating a band of food approximately 6-8 cm wide and 1 cm thick.
4. Sprinkle one-third of a bag of straw mushroom spawn on the supplementary food, placing the majority of the spore next to the inside border of the wooden mold.
Figure 20: Bed Preparation
(Note: In this example, a bed composed of three layers is being made. Hence, the use of one-third of a bag of spawn per layer. If the bed was composed of four layers, one-fourth of a bag of spawn would be used per layer. Five layers would require one-fifth of a bag per layer, and so on. Each bed constructed will use a total of one bag of mushroom spawn).
5. Place the presoaked rice straw or water hyacinth on top of the spawn-supplementary food layer. Press the straw or water hyacinth firmly into the bottom of the mold, filling the mold one-third full. This completes the first layer of the bed.
6. Repeat this procedure to complete subsequent layers, then water thoroughly with one or two buckets of water. The number of layers planted in one wooden mold varies according to the season: three layers in the hot season, four layers in the rainy season, and five layers in the cold season.
7. Remove the wooden mold and place it next to the first bed, lengthwise, leaving 12-16 cm between beds in the hot season and 8-10 cm in the cold and rainy seasons. Use the described method to plant as many beds as desired. Ten beds of straw mushrooms are commonly planted in one 7-meter row.
8. Loosen the soil between and around the beds in the row. Sprinkle supplementary food over this area and water thoroughly. Sprinkle one bag of straw mushroom spawn over the supplementary food between and around the beds in the ten-bed row.
Figure 21: Covering Straw Mushroom Beds
9. Cover the beds with two sheets of clear plastic, overlapping the sheets in the middle of the beds. Be careful not to let the plastic sheets rest against the sides of the bed as this will inhibit mushroom growth and greatly reduce mushroom production. Bamboo sticks can be used as supports to keep the sheets from coming in contact with the sides (and tops, if desired) of the beds. Wood, rocks and/or dirt should be used to secure the edges of the plastic sheets to the ground (see Figure 21).
10. Cover the plastic sheets with dry rice straw, as shown in Figure 22. This will prevent direct sunlight from shining on the beds which is likely to kill the spawn. If desired, an additional roof of coconut leaves (or other suitable material) can be built over the beds to further protect them from excessive exposure to sunlight and heat. This roof should be built high enough above ground level to allow people to walk comfortably under it.
Figure 22: Protection for Cultivation Beds
11. Check the moisture content of the beds on day 4. This is done by taking a sample of rice straw from one of the beds (one or two pieces of straw is adequate, examine samples from several areas in the row of beds) and twisting it. If much water drips from the straw sample, the beds are too wet and need to be dried. This is done by opening the plastic sheets over the middle of the beds, leaving an open space 5-10 cm wide, the length of the row. This will allow air to circulate within the row, thereby decreasing moisture content. It is best to open the plastic sheets for 5-15 minutes during the early morning and/or late evening, when the sun is low in the sky. This procedure reduces the chances of sunlight-induced spawn kill.
Figure 23: Checking Moisture Content of Straw
If 2-4 drops of water slowly fall from the twisted straw samples, the beds have adequate moisture. If no water drips from the straw, the beds are too dry and require watering. When watering, be careful to water around, not on, the beds.
12. If the weather is extremely hot (35°C and higher) during the first five days after planting, open the plastic sheets over the middle of the beds leaving an open space 5-10 cm wide the length of the row, as shown in Figure 24. This will allow air to circulate slowly within the row and prevent the spore from dying due to high temperatures. If the plastic sheets are opened, the moisture content of the beds should be closely monitored using the technique described in step 11.
Figure 24: Opening Plastic Sheet for Ventilation
13. White thread-like mycelium and possibly small mushrooms might be seen growing in the beds after 5-8 days.
1. Harvest will begin 9-11 days after planting. Pick the mushrooms by twisting them at their base in the straw bed. Straw mushrooms should be harvested before the head of the mushroom fully emerges, since this type of mushroom will bring the highest price.
Figure 25: Harvesting Straw Mushrooms
2. Initial harvest will be complete in 2-4 days. Thereafter, the beds may be watered with plain water, or water enriched with nitrogen (use fertilizer, 25-5-5 vegetable and flower fertilizer, or any other water-soluble fertilizer with a high nitrogen content). Water on top and around the beds. Cover once again with plastic and straw, and after 2-7 days a second, smaller harvest may be possible. One bed should produce a total of 0.5 to 1.0 kg of consumable mushrooms.
This handbook cannot describe all the methods used in the cultivation of straw mushrooms. The method described above is one of the common methods practiced throughout Thailand. It is not the only way to cultivate straw mushrooms. Do not be afraid to experiment or try other methods not described in this handbook. Use common sense.
Figure 26: Site Adjustment for Cultivation in Rainy Season
Straw mushrooms are usually grown in Thailand during the cool and hot seasons, following the harvest of rice. The reasons for this are obvious. First, the supply of rice straw is at its height and farmers are free to pursue other activities since their rice crops have been harvested. Second, because of the large number of producers cultivating mushrooms at the same time, supply is high and the market price is low during these seasons. Although it is possible to cultivate straw mushrooms during the rainy season, it is seldom done due to the lack of rice straw and farmer preoccupation with the rice crop. As one might expect, the market price for straw mushrooms is quite high during the rainy season. For example, in Ubon Ratchathani Province, prices may reach B40 or more per kilogram. Therefore, it may be worthwhile to encourage farmers to store rice straw for mushroom cultivation during the rainy season, or to use water hyacinth as the growing substrate. The technique used is the same as that described here, with the additional step of digging small channels between rows of beds in order to allow rainfall to drain away from the cultivation site, lessening the danger of flood damage to the beds. Farmers who are able to cultivate straw mushrooms successfully during the rainy season will be able to earn a good deal of extra income.
Storing rice straw for mushrooms cultivation