|Mushroom Cultivation in Thailand (Peace Corps, 1987, 85 p.)|
|6. Wood ear mushroom cultivation in wooden logs|
A hammer-punch or drill is needed to make the holes in the logs into which the spawn will be placed. The hammer-punch, as shown in Figure 32, is specifically designed to make the holes in wooden logs for wood ear mushroom cultivation. Hammer-punches are available at most outlets that sell wood ear mushroom spawn. While it is expensive--one hammer costs approximately B130-150 it is very easy to use, takes much of the work out of hole making, and can be used. for many years. It is not necessary for each farmer to have a hammer-punch; one can be purchased and kept at a farmer's house or at an agriculture extension office for many farmers to use as needed. However, if you don't want to use a hammer-punch, a common drill (manual or electric) will work as well. All that is needed is any available device that will make holes in the logs.
Figure 32: Hammer-Punch with Adjustment Head
An appropriate site is also needed to cultivate the mushrooms in the logs. The mushroom house described in the section concerning cultivation of mushrooms in plastic bags is equally well-suited for logs. Growing wood ear mushrooms in a mushroom house will allow a farmer to extend the growing season and take advantage of higher prices during the dry season. However, if a farmer does not wish to build a mushroom house, the wood ear mushroom logs can be stored easily and cultivated under a tree, out of direct sunlight, during the rainy season. The naturally moist and humid conditions prevalent during the rainy season make this method of cultivation possible and profitable and reduces labor, since if it rains, the grower does not need to spend time watering the logs.
Wood ear mushroom spawn, unlike angel, oyster and abalone spawn, is not sensitive to prolonged contact with water. Hence, it can and should be exposed to rainfall; the more the better. Conversely, angel, oyster and abalone mushrooms are not grown profitably when exposed to heavy rainfall, i.e., when cultivated under a tree with no overhead shelter. As previously stated, angel, oyster and abalone mushrooms will rot before reaching maturity if exposed to prolonged contact with water. For obvious reasons, wood ear mushroom logs will not produce well, if at all, when cultivated under a tree during the dry season.
With all materials gathered, the planting of wood ear mushroom spawn can proceed. The first step is to punch or drill holes in the logs where spawn will be planted. The holes should be 1.3-2.5 cm deep (the hole should be punched or drilled through the bark and into the hardwood section of the log, see Figure 33) and 12-15 cm apart. Make the holes in lines or a zigzag pattern all around the log. It is not necessary to make holes in the ends of the logs.
Figure 33: Log Preparation for Planting Spawn
Once the holes have been made, fill each hole to the top with spawn. Do not press the spawn into the hole too tightly. Simply place the spawn in the hole and pack gently, making sure that the hole is completely full.
Figure 34: Planting Wood Ear Mushroom Spawn
After placing spawn in the holes, seal the holes with bark, hardwood, plastic or wax plugs. If a hammer-punch is used, it will be possible to use bark or hardwood plugs as the hammer is sold with a removable head attachment designed to make cover plugs. Use a "trash log" to make the plugs, punching plugs out of the logs until it is impossible to punch anymore. Notice that the attachment makes plugs larger in diameter than the hole punched for spawn planting. This is to ensure a snug fit and to compensate for plug shrinkage as the wooden plug dries out. Hardwood plugs are usually better to use than bark plugs since the former tend to shrink less and are more likely to stay over the hole for a longer period of time.
To secure the plug in place, position the plug over the hole and strike the plug with a hammer or other hard object, driving it into the spawn-filled hole until the plug top is even with the surrounding bark. If a drill is used, and bark or hardwood plugs cannot be made, plastic plugs (available at most spawn outlets) or wax can be used to seal the hole. Plastic plugs are used in the same manner as bark or hardwood plugs and work well, but must be purchased, increasing total input costs. Wax also works well as a plug and can be purchased cheaply at most village temples. To use wax as a plug, first melt the wax, then allow it to cool before applying to the log. Hot wax should not be applied to the log as it will kill the mushroom spawn. While the wax is still soft, seal the holes, filling each with wax to the level of the surrounding bark.
Figure 35: Placement of Holes in Logs for Spawn Planting2
2 Adapted from Deeprom Chaiwongkeit, p. 76.
Figure 36: Storing Logs During Incubation
After the spawn has been placed in the holes and the holes sealed, the logs are ready to be incubated for approximately three weeks. It is important to incubate the logs in a place where the logs won't come in contact with direct sunlight, wind, or moisture. If exposed to sunlight or wind, the logs will dry too quickly, causing the spawn to die before spreading throughout the interior of the log. If exposed to moisture, the spawn will exert its energy to produce mushrooms rather than spreading to the interior of the log to produce more spawn. As a result, overall mushroom production would be very small and short-lived. Consequently, do not water the logs until the Incubation period is over.
The desired sequence of events is for the logs to dry slowly, with the spawn following the remaining moisture to the core of the log. The log will then be filled with dormant mushroom spawn by the end of the Incubation period. As mentioned before, the incubation period for 20 cm diameter log is approximately three weeks. Smaller diameter logs require a slightly shorter Incubation period, larger logs slightly longer.
After incubation, the logs are ready to be moved to the site of cultivation. The most common way to store logs for cultivation, and the method that makes mushroom harvest the simplest, is to lean the logs against a bamboo or wooden pole which is secured parallel to and approximately 70 cm above ground level (the pole can be as long as desired) as shown in Figure 37. The logs should lean against both sides of the pole in order to reduce stress. Once in place, the logs are watered several times daily. (Note: Many growers of wood ear mushrooms advise soaking the logs in water overnight prior to moving them to the site of cultivation in order to help encourage rapid initial mushroom growth. This will not, however, increase the total mushroom production of the logs.) It is impossible to water the logs too much. Wet, rotting logs provide the best atmosphere for wood ear mushroom growth! Logs that are moist at all times will yield large quantities of mushrooms.
Figure 37: Storing Logs During Mushroom Cultivation
Mushrooms will begin to appear around the holes approximately 10-15 days after the onset of watering. The first harvest will be possible about 21-30 days after the first watering if the logs are kept moist at all times. Time from initial watering to first harvest is directly related to the diameter of the log. The larger the diameter of the log, the slower the emergence of the first mushrooms and longer the period of mushroom production.
To harvest, pull the mature mushrooms (those from 3-6 cm in diameter) from the log at their bases. Subsequent harvests will be possible every 6-8 days. Over time, mushrooms will begin to grow all over the logs, even on the ends, and will continue to grow until the log has completely rotted. A 20-30 cm diameter log will produce mushrooms for about 5-10 months, depending on diameter, growing conditions and the type of wood used. One 1520 cm diameter, 1 meter long log will yield about 1-2 kg of fresh wood ear mushrooms.
Figure 38: Harvesting Wood Ear Mushrooms
Figure 39: Drying Wood Ear Mushrooms
Wood ear mushrooms can be very profitable for a farmer to grow due to the low investment, high yield possibilities and high market price. However, wood ear mushroom cultivation does have one major drawback: cultivation requires the use of fresh wood as a growing substrate. Advising and encouraging farmers to grow wood ear mushrooms can accelerate local deforestation, already a serious problem throughout Thailand. However, several steps can be taken to avoid deforesting the land and make wood ear mushroom cultivation possible almost anywhere in the country for many years to come.
Whole trees needn't be cut down in order to cultivate wood ear mushrooms; encourage farmers to trim their trees, and use the larger diameter limbs for mushroom cultivation. Trimming trees will also encourage rapid tree growth and high fruit or fiber production; it is a practice one should follow regardless of any desire to grow wood ear mushrooms. If farmers want to cultivate wood ear mushrooms on a large scale and cannot get enough tree limbs to use as a growing substrate, whole trees may need to be felled. If this must be done, encourage farmers to thin out their old, diseased or otherwise unproductive trees and use them for mushroom cultivation, leaving younger, stronger trees to grow to maturity and provide fruit or fiber for local consumption.
Finally, always encourage farmers to plant more trees than they cut. Many varieties of seedlings are available free of charge from government nurseries. Encourage and assist farmers in taking advantage of this service and plant trees! Some fast growing tree varieties (e.g., Katura, or) can be planted and harvested for mushroom cultivation after only 3-4 years of growth. Encourage tree planting! Using good foresight and proper extension techniques, any agricultural extension agent can make wood ear mushroom cultivation a profitable undertaking for any farmer without depreciating or destroying local resources.