Shiitake (she-e-ta-kay), the Japanese forest mushroom (Lentinus edodes), is a nonpathogenic fungus that can be grown on a variety of currently underutilized logs. Shiitake cultivation began in Japan centuries ago when wild shiitake was collected in the forest. Today Japan accounts for approximately 80 percent of the total annual world production of 200,000 metric tons.

Shiitake is developing into a gourmet item in select U.S. restaurants, grocery and speciality food stores. When cooked, shiitake imparts a full-bodied aromatic but distinctly pleasant flavor to the dish while maintaining its own original color and chewy texture. Shiitake is easily dried and rehydrates well.

Six Cultivation Steps

Successful shiitake cultivation is not necessarily difficult. It should be remembered, however, that the grower is trying to harness and improve on a process that evolved in nature. Mushrooms are dependent on the environmental conditions similar to those found in a forest. There are six key cultivation steps, each of which requires careful attention:

Obtaining viable spawn (inoculum) in pure culture and storing it until use – Commercial shiitake spawn suppliers are located throughout the U.S. and Canada. Ohio residents can easily order spawn and have it shipped to them. Spawn is sold on essentially two mediums: sawdust and wood dowels. Obtaining and preparing logs for cultivation – The species of tree selected for shiitake cultivation is important. Oaks are the preferred species in Japan and have given promising results in the United States. Trees are felled during the dormant season and cut to length (3 to 5 ft.) prior to inoculation. Inoculation – Inoculation is the introduction of the live fungus (spawn) into the log. Holes are drilled into the log and the spawn is placed into the holes either by hand or mechanically. The process is completed by sealing the inoculation sites with hot wax or plastic foam plugs. Laying the logs (to favor fungal growth) – Logs are often laid side by side, propped up at a slight angle in a well-drained, shaded area with single logs placed crosswise between rows. Logs may be turned (reversing the ends) every 2 to 4 months to encourage uniform water distribution and fungal growth. Raising the logs (to favor fruiting) – Shiitake is capable of fruiting only after the fungus has completely colonized the log (6 months to 2 yrs.). Fruiting occurs primarily in the wet, cool seasons (spring and autumn) but adequate rainfall during the summer months can stimulate fruiting, especially with certain strains or varieties. When conditions are favorable for fruiting, logs can be arranged in rows (against a fence for example) in an upright position on well-drained, shaded ground. An upright stacking arrangement facilitates harvesting the mushrooms. Harvesting and crop storage – Once mushroom formation has begun, shiitake often matures in 2 to 7 days. The mushrooms can be either snapped off cleanly or cut with a knife at the log surface. Fresh mushrooms intended for market should be refrigerated immediately after harvest.

Obtaining Spawn, Obtaining and Preparing Logs, and Inoculation

In nature, the shiitake fungus propagates and spreads from spores produced by the mushroom. However, for cultivation, spore germination is too unreliable. Instead, logs are inoculated with actively growing fungus. The fungus is first adapted to wood by growing it directly on small pieces of wood. Active fungal cultures intended as inoculum for mushroom cultivation are called spawn. Because the quality of the crop can be no better than the spawn, growers must use viable shiitake spawn of a good variety in pure culture, free of weed fungi and bacteria.

Spawn Strain Characteristics

Different cultivars or strains of shiitake may perform differently under different conditions. Initially, growers should try more than one strain to ensure success. Also, growers can extend the growing season by using strains that fruit under different environmental conditions. For example, a grower in southern Ohio could use a cold-weather strain for spring and fall production, and a heat-tolerant strain for summer production.

The following strain characteristics need to be considered when ordering spawn from commercial suppliers:

Preference for type of wood

Resistance to weed fungi

Speed of colonization (time of first fruiting)

Ease of fruiting

Season of fruiting

Ability to stimulate (force) fruiting

Required temperature for fruiting

Size, shape, color and flavor of mushrooms

Mushroom storage characteristics

The individual grower will need to experiment with different strains and decide which work best in a particular situation.

Sources of Spawn

There are numerous spawn suppliers throughout the United States and Canada. In addition to experimenting with different strains, growers are encouraged to purchase spawn from more than one spawn supplier. Many spawn suppliers also sell equipment and supplies related to mushroom growing; product catalogs are often available from them upon request. Fact Sheet F-39 Shiitake Mushroom Production: Introduction and Sources of Information and Supplies, includes an up-to-date list of spawn suppliers. It is available from your county office of Ohio State University Extension.

Forms of Spawn

Shiitake spawn can be purchased on two mediums: sawdust and wood dowels. It is usually supplied in either sealed plastic or glass containers. The spawn should be moist, white (sometimes with a brown crust) and appear rather fuzzy. Good quality spawn smells mushroom-like, not mildewy or mold-like. Weed fungi and bacteria are controlled by not damaging or opening the spawn container until use of the entire contents.

Spawn Storage

Spawn must be kept away from direct sunlight and temperature extremes. Storage for a month or more should be in a cool (34-38 F) location away from direct sunlight. Spawn must not be frozen. Prior to inoculation spawn should be warmed to room temperature (70 F) for two to five days.

Obtaining and Preparing the Logs

Trees cut for shiitake mushroom production should be harvested as part of an overall forest management plan. Individuals interested in producing shiitake mushrooms from their woodlot should contact a forester for assistance in selecting the appropriate trees.

Suitable Tree Species

The hardwood tree family most recommended in the United States for shiitake cultivation is the beech family (Fagaceae). The particular genus most successful in this family is Quercus (oak). All oak trees can be used with the possible exception of live oak. The thicker bark oaks such as white and chestnut oak are often preferred over the thinner bark red, scarlet and pin oak.

Beech, birch, chestnut, chinkapin, alder, maple, cottonwood, willow, aspen, poplar, elm and hophornbeam are suitable species but may have commercial limitations. As a rule, the thin-barked low-density species provide relatively quick mushroom production but only for a short time period. Locust, walnut and all conifers are not suitable for shiitake cultivation.

Sweet gum (Liquidambar styraciflua) and sycamore (Platanus occidentalis) have outperformed oak species in selected trials in North Carolina. Other species may prove to be excellent for shiitake cultivation once testing is completed.

Tree Quality

Logs used for shiitake production must be cut from live, healthy trees. Living trees with obvious insect or disease damage should not be used.

Optimum log size is 4-8 inches in diameter and 3-4 feet in length; standard lengths make operations much more convenient. Logs with a thick sapwood layer and small heartwood area are preferred. Logs can be cut from young hardwood trees or branches of older trees.

Logs should be straight for ease in handling but crooked logs can be used. A smooth bark will make the inoculation (seeding) process easier but thin bark tends to crack and peel sooner than thick bark. Regardless of thickness, the bark must be intact on the log.

Tree Felling

Some authors suggest the optimum felling time is when 30 to 80 percent of the tree leaves on the chosen species have changed color. Others suggest tree felling during the coldest time of winter. One reason for the different opinions on tree felling is due to the different theories on the best time to inoculate (seed the logs). Most shiitake growers and researchers agree, however, that trees should be felled sometime during the dormant season (mid-autumn to late winter), before spring sap movement and bud swell.

Logs should not be used for shiitake production if they were cut from felled trees that seasoned during the summer months. For example, trees cut prior to the summer months (even if cut while dormant) should not be used after being exposed to the warm weather conditions of summer.

Log Preparation

After tree felling, logs need to be prepared for inoculation. Regardless of the method of log preparation, two areas need careful attention: the moisture content of the log needs to be maintained above 35 percent and potential log contaminants must be minimized.

One method of reducing moisture loss is to keep logs in whole tree lengths and cut to final log size prior to inoculation. Rain and snowfall can be permitted to wet the logs. If trees must be immediately cut to final log length, logs should be protected from drying winds and direct sunlight by covering with burlap, shade cloth or plastic. If possible, logs should be stacked firewood-style in full shade under conifers. Watering or soaking logs is recommended several days before inoculation if the moisture content drops below 35 percent. Log surfaces should be allowed to dry prior to inoculation.

Log contaminants (insects, diseases, etc.) can be reduced by storing the logs off the ground. Tree length logs can have the butt supported on the stump. Logs cut to length can be placed on pipe, concrete blocks or other suitable material that will keep them off the ground. If stacking logs in contact with the ground, select a well-drained site with good air circulation and use cull logs as supports.

When logs are cut to final length, plan all cuts to give the most good logs. All diseased and wounded sections, forks, crotches and major kinks should be cut out. Small branches should be removed from logs, leaving a stump of approximately two inches. A wire brush can be used to remove lichens and moss from the bark prior to inoculation.

Inoculation

Inoculation is the introduction of the live shiitake fungus into the log. A one-time inoculation will produce mushrooms after 6-18 months and will continue to produce for 3-6 years.

In the past, logs were normally cured after felling for at least two weeks before inoculation. However, many researchers and spawn suppliers are now recommending inoculation as soon as possible after felling. Also, early spring inoculation is now being replaced by fall and spring inoculation. Inoculation should always be done in a shaded area to avoid direct exposure of the spawn to sunlight.

Logs should be watered if the internal log moisture content drops below 35 percent prior to inoculation. Occasional thorough waterings are better than frequent light waterings. The former will increase the internal log moisture content while the latter often just wets the bark surface.

Personnel, Equipment and Supplies Needed

While the entire inoculation process can be done by one person, a minimum of three is suggested: one person to drill holes, one to place the spawn in the holes and one to seal the inoculation sites. A fourth person can be useful in moving logs from one work station to the next.

In addition to the spawn, equipment and supplies needed for inoculation are: drill (preferably high speed if many logs are to be inoculated), bits, work table or saw buck, yard stick or measuring tape, hammer (for dowel spawn), inoculation tool (optional, for sawdust spawn), paraffin/cheese wax/plastic foam (for sealing inoculation sites), heat source (for melting wax), wax dropper or brush (for applying wax), and rubbing alcohol.

Inoculation Procedure

Logs to be drilled should be secured in a saw buck or similar arrangement to prevent the logs from moving (Figure 1). The log bark should be free of dirt and other possible contaminants. Dip the drill bit in rubbing alcohol after finishing each log as a precaution.

The hole-drilling pattern will vary from grower to grower. A general recommendation is to space holes 6-16 inches within rows and 2-4 inches between rows since the shiitake mycelium runs well with the grain but poorly across the grain. Adjacent rows should be offset from one another to create a diamond pattern on the log (Figure 2).

Depth and diameter of the holes will depend on the source as well as the form of spawn. Hole depth generally ranges between 3/4 and 11/4 inches with hole diameter between 1/4 and 1/2 inch. Most spawn suppliers will recommend dimensions for hole size. After a log has been drilled, holes should be filled immediately so as not to lose moisture or permit entry of airborne spores.

Hands should be washed and then wiped with rubbing alcohol before handling spawn. On a work table or second saw buck, dowel spawn can be placed into the holes and then gently pounded in with a hammer. A convenient method is to initially hold the dowels with forceps. Sawdust spawn can either be inserted manually or with an inoculation tool available from many spawn suppliers. Disagreement exists as to whether the sawdust spawn should be packed tightly in the hole or just lightly tamped in. Growers are advised to follow the spawn supplier’s recommendations.

The final step in the inoculation process is to seal the spawn-filled hole with either a paraffin or cheese wax or styrofoam plug. Holes are sealed to prevent loss of moisture, to prevent contamination by undesirable microorganisms and to allow the spawn to grow within the confines of the log. Hot wax also tends to disinfect the inoculation surface. Melted wax can be applied by brush or wax dropper (similar to a turkey baster). Styrofoam plugs are placed on top of the spawn, flush with the surface of the bark.

Suggested Practices After Inoculation

All inoculated logs should be coded to record important information such as spawn strain, tree species, etc. Small aluminum tags fastened to log ends with a staple work well for this purpose. Good record keeping will enable growers to duplicate successful practices by learning from past experiences.

Inoculated logs may be dead piled (firewood style) and shaded with plastic immediately following inoculation. If the log moisture content is low, burlap or similar material should be used to allow rain to reach the logs. If surface molds develop, logs should be moved from temporary to a permanent laying position.

Logs and Laying Yards

Following log inoculation, the shiitake mushroom grower’s objectives are to maintain log moisture content above 35 percent, ensuring speedy, vigorous colonization and to provide an environment with enough ventilation to retard excessive growth of weed fungi. Also, logs should be adequately protected from drying that is so abrupt or severe as to cause shrinkage and cracking or checking on log surfaces. Even small cracking or checking of the bark provides extra surface area for drying and new sites for weed fungi to enter the log.

The choice of location for a laying yard and the choice of log stacking methods can greatly diminish the need for management activities such as irrigation, the use of temporary covers to screen wind and sun, etc. If, for example, the laying yard is a high, open, windy, sunny hilltop, the drying rate of logs might necessitate regular and frequent irrigation and artificial windscreens, sun screeens or coverings on the logs. A different location nearby might be more favorable: lower winds, less sun, higher humidity and less active management.

Stacking methods also affect log moisture content and drying rates. Figure 1 shows four types of stacks: dead piling (or firewood style), “X” (or “A”) frame stacking, crib stacking (or cross-hatch) and lean-to (or diagonal) stacking.

Dead Piling

Dead piling is used mainly for short-term storage, as when logs come off the inoculation line, or for early incubation (temporary laying), with a moisture resistant covering of cloth, plastic, etc. to conserve moisture and shed rain.

Dead piling is not used indefinitely because of the lack of ventilation and potential for contamination if heavy rains penetrate the stack or condensation occurs. Dead piling and covering are probably useful only until the logs require moisture replenishment because of drying or water consumption by spawn growth.

X Frame Stacking

This stacking method is suited to long-term laying only on humid and calm sites, where other stacking methods lead to excess surface moisture and mold growth. Due to low density (space efficiency) and high ventilation, it has limited use for most growers during the spawn run. It may be more useful during fruiting periods with higher humidity and lower drying rates.

Crib Stacking

Cribbing during spawn run (long-term laying) is probably best suited to airy locations in consistently humid climates with ample, regular rains. However, it has potential for problems. Rain shadow effects can be pronounced. Ventilation and relative humidity tend to vary from top to bottom and from inside to outside of the stack. Solar gain and temperature are also unequal from side to side and top to bottom. The higher the cribs are made, the greater the variances.

On the plus side, cribbing can yield good space efficiency and it is simple and convenient. While some growers may find it to be economical, relatively few will find it to be biologically optimum.

Lean-To Stacking

Lean-to stacking is probably the most broadly applicable method. It is certainly the most flexible method, and can provide a high degree of uniformity throughout each stack.

Lean-to stacking enables the grower to maximize or minimize rain shadow effects by either using the same number of logs “vertically aligned” in each course or by setting them out of alignment (Figure 2). Rainfall exposure may also be varied by changing the angle of logs. The nearer to vertical the logs, the less surface area exposed to rain; the nearer to horizontal, the greater the exposure (Figure 3). Additionally, steeper angles may also speed runoff of rain from the log surface.

Angle of stacking with this method also affects air flow in the stack. Air flow increases distinctly at even small elevations above the ground surface. In stacking at low angles, not only are logs in a zone of normally lower air speeds, but the low stack is more apt to deflect air movement aloft, while the higher stack will allow more air penetration. Angle of stacking will also affect the relative humidity of the air to which logs are exposed. Just as air speed changes with small elevations, so does relative humidity of the air. Relative humidity may be quite different at three inches above the ground than it is at three feet. This difference is more pronounced on some sites than others. Wet or heavy soils and low vegetation that transpires moisture (grass for example) accentuate this effect.

In practice, lower stack angles are appropriate for relatively dry climates or sites and for log sizes or species that are prone to excessive drying. Steeper angles are indicated with humid, rainy climates and calm sites or with logs less prone to drying. Growers who experiment with lean-to stacks will often find that changes of stack angles of five degrees cause significant differences in log moisture content over several weeks or months.

A management opportunity that is unique to lean-to stacking is the ability to regulate solar gain of the logs, in turn regulating the daytime temperatures of the logs. Lean-to stacks with the north ends of leaning logs elevated give each log higher solar gain than stacks with south ends elevated.

A grower in a cool climate can use this effect to speed colonization by warming the logs somewhat. This arrangement can also lengthen the growing season in the spring and fall in many locations. Growers in very warm climates might elevate south ends of logs to minimize solar gain (Figure 4). Optimum temperature for spawn growth is 72 F-78 F (log temperature) and temperatures above 105 F are generally lethal.

Solar gain is greatest where there is full sunlight but will still be present under forest shade or most types of shade cloth. Growers may also alter stack orientation to reflect other site specific conditions such as openings in a forest canopy, direction of prevailing winds or up-slope/ down-slope air currents that occur in hilly terrain due to daily heating and cooling.

Summary

The variables and effects in lean-to stacking that have been discussed apply to the other styles of log stacking as well in varying degrees. It should be emphasized though that most other methods will not yield the same uniformity of drying rates, moisture regain, ventilation and solar gain. A shiitake grower who has not experimented with a wide variety of stacking methods may be missing important opportunities, not only in providing optimum spawn growth and reducing contamination but also in making the best use of weather and minimizing labor and material input.

Fruiting, Harvesting and Crop Storage

Fruiting

Shiitake logs are ready to fruit when the shiitake has colonized the outer cylinder of available sapwood. At this point (6-24 months), the mycelium has stored enough nutrients to form mushrooms.

An obvious sign of mature logs is the appearance of mushrooms. Other signs that indicate a readiness for fruiting are: elastic and spongy bark, logs that no longer “ring” when struck, and (under moist conditions) white mycelium appearing on log ends that are traceable to inoculation holes near the log ends.

Log Soaking

Temperature and moisture changes trigger the shiitake fungus to produce mushrooms. Therefore, log soaking is often used for “forced fruiting” and is done at a time planned by the grower.

Log soaking (complete immersion in water) can be done by various methods, such as using stock tanks, ponds or streams. The length of soak depends upon air and water temperature, log age and bark thickness. As a rule, the closer the air (log) temperature to water temperature, the longer the soak. For example, soak time in the summer is usually 6 to 24 hours with 2-3 days the rule in the cool spring or fall. Older logs and thin barked logs absorb water quickly and do not require as long a soaking time as younger or thick barked logs.

Log Stacking and Protection

After logs are soaked they are stacked for fruiting, normally using the X frame or lean-to configuration. Regardless of the stacking arrangement, all sides of each log should be accessible for harvest (Figure 1).

Logs stacked outdoors can use a protective covering to minimize wind and rain, stabilize temperatures and localize humidity around the logs. Burlap and plastic should be used with care and are recommended only for experienced growers. Fruiting (humidity) blankets, which are a better choice for the grower, are porous, white, synthetic, felted material that hold water, allow air movement and provide some insulation.

Environmental Conditions

“Pinning,” which is the development of very small mushrooms, occurs as the logs dry. Whereas well-colonized soaked logs can have moisture contents as high as 80 percent to 90 percent, pinning requires a log moisture content of 35 percent to an optimum of 60 percent.

Optimum temperatures for pinning are between 55 F and 65 F with relative humidities of at least 85 percent.

Light is not required for spawn run, but is required for fruiting (enough light to read a newspaper at arm’s length). If shiitake is fruited indoors, approximately 30 foot-candles of light should be used.

Fruiting Period

Once the “pins” have emerged (3-10 days after soaking), the protective covering should be removed to expose more of each log and to produce dry, firm mushrooms. Depending on the temperature and shiitake strain, the fruiting period usually lasts from one to two weeks. A grower can extend the natural outdoor fruiting season through use of combinations of different strains (cold weather, warm weather and wide range), soaking and log coverings (to prevent natural irrigation and unplanned fruiting).

After mushrooms are harvested, logs should be placed in a laying position and rested for one to three months. Log moisture content should be maintained from 30 percent to 40 percent to promote mycelial growth while inhibiting pinning. Warm temperatures (60-77 F) speed recovery of the logs, after which time they can be soaked (forced) for another flush or crop of mushrooms.

Harvesting

Shiitake mushrooms, growing on one log or a group of logs, will not usually develop at the same time. Therefore, logs must be checked frequently and mushrooms harvested at just the right time to maximize quality.

Shiitake should be picked when the cap is opened approximately 50 to 75 percent (Figure 2). At this stage the gills are exposed but the cap edges are still rolled under the cap. Harvesting mature mushrooms (cap 100 percent opened) can lead to reduced shelf life, a longer delay before the next flush and increased pest problems.

Picking

Shiitake are picked by grasping the lower portion of the stem and, with a slight twisting motion, pulling the mushroom from the log. Shiitake can also be harvested by cutting them as close as possible to the log surface with a sharp knife or scissors. Since bruises on the caps and gills will discolor rapidly, only the stems should be touched during picking.

Picking mushrooms from the bottom of the log and working up can minimize the accumulation of bark flecks and other debris on unpicked mushrooms. Also, after shiitake are picked, the stems can be trimmed to remove debris.

Picked mushrooms can be put into a basket, box, paper bag or other suitable container. Air vents in the container are recommended so the shiitake can be cooled rapidly. To prevent bruising and promote rapid cooling, picking containers should not be filled more than four to six inches deep with shiitake.

Storage

The immediate objective after picking is to cool the shiitake to 33-36 F as rapidly as possible. The use of plastic “crates” or baskets that are slatted on all sides are recommended for refrigerator storage. Mushroom shelf life is reduced dramatically by using containers that do not allow rapid cooling. Also, frost-free refrigerators tend to dry mushrooms excessively.

The storage life of shiitake is similar to that of Agaricus (common button mushroom) and is highly dependent on temperature. For example, at 32 F Agaricus can be stored for 17 to 20 days but at 37 F the storage life is 7 to 10 days.

Costs of Growing Shiitake mushrooms

Shiitake mushrooms are cultivated from at least two different grower perspectives. First, some individuals raise shiitake as a garden crop, producing enough for personal consumption. These individuals can be thought of as “hobbyists.” Second, many individuals pursue shiitake production from a commercial perspective with a goal of maximizing economic return.

The shiitake hobbyist is able to achieve success with a minimum investment since many of the “tools of production” are usually already owned or easily obtainable: hardwood logs, natural shade, electric drill, garden hose and sprinkler, etc. For many backyard gardeners, shiitake spawn is the only out-of-pocket expense necessary to get started. Although spawn prices vary, a rule of thumb is $1 of spawn per four-foot log.

The commercial grower, however, should not expect to operate a profitable shiitake enterprise using hobbyist tools and supplies. Also, the commercial grower must become an expert shiitake marketer in order to realize an economic gain.

Commercial Production Inputs

The following “inputs” are recommended for a commercial grower inoculating 4,000 logs per year for a 15-year planning period.1

Operating Expenses

Log Covers Plastic and fabric

Tools and Supplies Sawdust spawn inoculation tool Staple gun Log drilling stand (sawbuck) Electric drill (high speed) Drill bits Electric extension cord Wax melting pot Wax baster or brush Water hose/sprinkler head Scale for weighing logs (to determine moisture content) Mushroom picking/storage baskets Laying yard maintenance materials Steel racks for carrying/soaking logs Office supplies Tractor operation/maintenance

Utilities Outdoor – water/electricity Indoor (optional indoor fruiting during winter) – water/electricity/heat

Advertising

Shipping Packaging and labels Transportation

Interest on borrowed money

Capital Expenses

Logs Purchased logs Spawn Wax or plastic foam plugs Aluminum identification tags and staples

Soak Tanks Concrete vault

Laying Yard Shade cloth, wooden poles, and steel cable (to hold up shade cloth)

Tractor Used farm tractor with front end lift Trailer for moving logs

Refrigerator

Scale Electronic digital readout (for weighing mushrooms)

Building (indoor operation only)

With the management scenario noted above (4,000 logs inoculated per year for a 15-year planning period) and assigning costs to the operating and capital expenses, growers who invest their own labor and capital may produce a 6.48 percent after-tax rate of return plus equivalent annual incomes of $14,426 for outdoor production and $19,877 for indoor production after taxes. These financial returns require the input of approximately one person-year of labor annually. An outdoor shiitake grower, however, would incur revenue losses of $22,000 in the first year and would not turn a profit until the fifth year. An indoor shiitake grower would incur revenue losses of $94,000 in the first year and would not begin making a profit until the fourth year. Indoor production is potentially more profitable, but requires a much higher investment to get started. Financial returns are not sensitive to individual cost items, but are moderately sensitive to revenues. Revenues are dependent on pounds of mushrooms produced and the price per pound at which mushrooms are sold. Potential growers should read the Baughman (1989) article for a detailed description of the economics of shiitake production.

Factors Affecting the Economics of Shiitake Production

Numerous factors will have an impact on whether or not shiitake production can be a profitable business. Highlighted below are three of the more important factors.

Grower Experience Since shiitake production is relatively new to the United States, most potential growers have little or no practical experience. Therefore, grower inexperience in the early years of the enterprise will affect profitability. Most shiitake economic scenarios, however, assume the grower is knowledgeable about all phases of production.

Mushroom Yield

It is relatively easy to determine the cost of spawn or a new high-speed electric drill. However, it is difficult and risky to predict future yields of shiitake. Different strains of shiitake have resulted in significantly different yields even when management practices are held fairly constant. For example, Ohio State University Extension found an 11-fold yield difference between high and low producing strains. The Forest Resource Center in Minnesota reported yield variations between strains as high as 65-fold.

Marketing

For most individuals, growing shiitake mushrooms will be easier than selling them. Many growers invest time and money in production and devote little effort towards marketing. Even though shiitake is becoming more popular throughout the United States, growers must be excellent marketers as well as producers in order to succeed financially. Extension Bulletin #803, available from Ohio county Extension offices, provides an in-depth overview of marketing shiitake mushrooms.

Future Outlook

The future looks promising for the production of shiitake mushrooms on hardwood logs. Ohio is strategically located for producing this crop since the state has a large population (potential consumers) and an adequate supply of hardwood timber (excellent supply in eastern and southern Ohio).

Potential growers should be cautioned however that successful shiitake production can be quite labor-intensive and growers usually do not master all cultivation practices on their first attempt. In addition, growers will need to not only master the six cultivation steps but also will need to be excellent marketers as well.

Shiitake mushrooms are also being grown in the United States on artificial sawdust logs in environmentally controlled growth chambers. Shiitake growers associations have been formed in a number of states. The news media has provided the shiitake industry with a wealth of free publicity. These and other factors are increasing the general public awareness of shiitake.

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