Shiitake Mushroom Production: Steps to Cultivation and Considerations for Production

The majority of Ohio’s 8.1 million acres of forestland could benefit from timber stand improvement (TSI) or related forest-management practices. One of the disincentives for practicing TSI is that landowners often do not get an immediate economic return when they remove low-quality trees from their woodlot. Many rural landowners are also exploring possibilities for alternative crops and sources of income. The production of shiitake mushrooms on small-diameter (4–8 inches), low-quality logs presents an opportunity for these landowners to grow a specialty crop as an agroforestry practice and supplement their income.

Shiitake (she-e-ta-kay), or Lentinula edodes, can be grown on a variety of underutilized tree species. It is a white-rot fungus that is nonpathogenic to plants. The name “shiitake” originates from Japan and translates into shii mushroom, named after the shii tree. In recent years, shiitake mushroom sales in the United States were estimated to be over $27 million from 2021 to 2022, which is up $3 million from 2019 to 2020. These mushrooms are high in protein and, when cooked, impart a full-bodied aromatic but distinctly pleasant “meaty” flavor while maintaining color and chewy texture.

What to Consider for Shiitake Cultivation

Cultivating shiitake mushrooms on logs as a hobby or as part of a diversified operation is a great way to reduce waste and generate some income, especially when done with TSI. Ohio growers have access to the materials required for this venture, including unmarketable logs (also known as bolts or poles) left over from a timber harvest.

However, before starting with shiitakes as part of a business model, keep in mind that shiitake mushroom production is labor-intensive. Cultivation of shiitake mushrooms is not mastered in the first attempt. The biggest cultivation hurdle is not so much growing the mushrooms but marketing them. Demand needs to be present where shiitakes are sold. It is not feasible to grow shiitake mushrooms as a stand-alone large-scale commercial production operation without substantial market development and a large resource base from which to collect materials.

In addition to outdoor log production, shiitake mushrooms grow on artificial sawdust logs in environmentally controlled growth chambers. These chambers range from inexpensive homemade products to high-tech equipment that costs thousands of dollars. However, this fact sheet focuses on growing shiitakes on logs as part of an agroforestry practice.

Six Steps to Cultivation of Shiitakes

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 environmental conditions found in a forest. Six key cultivation steps require careful attention. Each of these steps is described in more detail in the Ohioline Shiitake Mushroom Production series:

• F-0040 Shiitake Mushroom Production: Inoculating Logs with Spawn
• F-0041 Shiitake Mushroom Production: Logs and Laying Yards
• F-0042 Shiitake Mushroom Production: Fruiting, Harvesting, and Storage
• F-0105 Shiitake Mushroom Production: Troubleshooting

1. Obtain Viable Spawn (Inoculum) and Store Until Use

Ohio residents can easily order spawn and have it shipped to them. Commercial shiitake spawn suppliers nationwide have spawn available on several types of media—grain, sawdust, and wood dowels. For shiitake production on logs, use sawdust and wood dowels. Spawn is best used within a few months of harvesting logs. Delaying inoculation could reduce the productivity of logs. Because spawn is bulky and can readily fill up a fridge or cold room, it is necessary to identify and prepare space for spawn storage that is available until inoculation. Do not freeze spawn.

When having spawn shipped, keep in mind that it may be harmed by temperature extremes. Always review the spawn requirements listed on the supplier’s website before ordering. Open the shiitake spawn package immediately and inspect for quality—do not let packages sit unopened for extended periods of time. Contact the supplier immediately if issues with the spawn are determined during inspection.

2. Obtain and Prepare Logs for Cultivation

The species of tree selected for shiitake cultivation is important. Oaks work well for shiitake production, with white oak species (e.g., white, bur, and chinquapin) preferred over red species (e.g., northern red, black, pin, and scarlet). However, American beech, ironwood, sugar maple and sweetgum are also excellent producers. Red maples can be used, but research has indicated that it is not financially sustainable for commercial operations. Elm, soft hardwoods (e.g., cottonwood, buckeye, aspen), evergreens, and fruit trees are not recommended. Ideally, logs used for shiitake production should be 3–4 feet in length with a diameter of 4–6 inches, although larger logs may be used.

3. Inoculate Logs with Spawn

Inoculation is the introduction of the live fungus (spawn) into the log. Holes spaced 3–4 inches apart are drilled into the log (Fig. 1). Rows of holes should be spaced 3 inches apart, or roughly one row per inch of log diameter. Inoculation may be conducted by hand or mechanically. Once inoculated, holes are sealed with wax. Sealing both ends of the log is not recommended as this can lock out moisture needed for the fungus to develop. Another option is to cap the existing holes with Styrofoam plugs in place of wax. Tools to do this are usually more expensive but also save time and effort during cleanup compared to wax. See F-0040 Shiitake Mushroom Production: Inoculating Logs with Spawn for more information on inoculating logs.

4. Layer the Logs for Colonization (to Favor Fungal Growth)

Logs are often laid side by side and are propped up at a slight angle in a well-drained, shaded area. Single logs are then placed crosswise between log rows. Logs may be turned (reversing the ends) every two to four months to encourage uniform water distribution and fungal growth.

5. Raise the Logs (to Favor Fruiting)

Shiitakes produce fruiting bodies, or mushrooms, once logs have been completely colonized by mycelia (singular: mycelium). This process takes six months to two years. A mycelium is composed of fine filamentous threads called hyphae (singular: hypha) that transport water and nutrients. 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. The effect of rainfall is simulated by submerging logs in cold water overnight to force fruiting to occur, although it is recommended to allow the first flush of mushrooms to occur naturally. Not all strains of shiitake respond to forcing. Cold-weather strains and some warm-weather strains do not respond well to forcing, while all wide-range strains can be forced. During cooler months, when natural fruiting occurs, forced fruiting requires the logs to be submerged for 36–48 hours to stimulate the development of fruiting bodies. When conditions are favorable for fruiting, arrange logs in rows (against a fence for example) in an upright position on well-drained, shaded ground. An upright stacking arrangement facilitates mushroom harvesting.

6. Harvest and Store Mushroom Crop

Once pinning (mushroom formation) has begun, the shiitake mushroom often matures in two to seven days (Fig. 2). The mushrooms can be either snapped off cleanly or cut with a knife at the log surface. Fresh mushrooms intended for the market should be refrigerated immediately after harvest.

Economics of Production

Shiitake mushrooms are cultivated from at least two perspectives. They can be raised by hobbyists as a garden crop, producing enough for personal consumption. Commercial growers pursue a goal of maximizing economic return.

The shiitake hobbyist can achieve success with a minimum investment since many of the tools of production are already owned or easily obtainable:

• hardwood logs
• natural shade
• electric drill
• garden hose
• sprinkler

For many backyard gardeners, shiitake spawn is the only out-of-pocket expense necessary to get started.

The commercial grower, however, should not expect to operate a profitable shiitake enterprise using hobbyist tools and supplies (Table 1). Also, the commercial grower must become an expert shiitake marketer to realize an economic gain.

For both indoor and outdoor production on a commercial scale, losses should be expected in the first few years before turning a profit. 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 research their local markets for fresh shiitake mushrooms before getting started.

Factors Affecting the Economics of Shiitake Production

Numerous factors will have an impact on whether shiitake production can be a profitable business.

Many shiitake growers have little or no practical experience. Therefore, grower inexperience in the early years of the enterprise will likely affect profitability. Most shiitake economic scenarios, however, assume the grower is knowledgeable about all phases of production.

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 constant. For example, Ohio State University Extension found an 11-fold yield difference between high- and low-producing strains. The Southeastern Minnesota Forest Resource Center reported yield variations between strains as high as 65-fold.

For most individuals, growing shiitake mushrooms will be easier than selling them. Many growers invest time and money in production and devote little effort toward marketing. Growers must be excellent marketers as well as producers to succeed financially. It is important for growers to identify and communicate with prospective outlets to determine how much product they may be interested in purchasing before production begins. Value-added production is one method to increase demand. Dried mushrooms, for example, can be sold and distributed to a wider market based on the longer shelf life but require commercially licensed facilities for dehydration and packaging. One may come across shiitakes at grocery stores, specialty stores, and restaurants. Growers can direct-market to these businesses as well as to buyers at farmers markets. It is a best practice to start small and build these markets over time.

Spawn Suppliers

Table 2 is a listing of companies that sell shiitake mushroom spawn or specialized equipment. Most that sell spawn also sell related products, such as inoculation equipment, humidity blankets, books on shiitake cultivation, and more.

Recommended Reading

Many publications are available for those who would like to consider shiitake mushroom production:

• Best Management Practices for Log-Based Shiitake Cultivation in the Northeastern United States from Northeast SARE is a must-read and is available as a free PDF at uvm.edu/sites/default/files/media/ShiitakeGuide.pdf
• Shiitake Growers Handbook: The Art and Science of Mushroom Cultivation by Paul Przybylowicz and John Donoghue
• Organic Mushroom Farming and Mycoremediation: Simple to Advanced and Experimental Techniques for Indoor and Outdoor Cultivation by Tradd Cotter
• Shiitake Mushroom Cultivation in the Northeast United States by Willie Crosby & Fungi Ally LLC. This is a free downloadable pdf available at
  northeast.sare.org/resources/shiitake-mushroom-cultivation-in-the-northeast-united-states
• Farming the Woods: An Integrated Permaculture Approach to Growing Food and Medicinals in Temperate Forests by Ken Mudge and Steve Gabriel
• Growing Gourmet and Medicinal Mushrooms by Paul Stamets
• Developing a Viable Log-Grown Shiitake Farming Enterprise in New York State is a free downloadable PDF available at
  cpb-us-e1.wpmucdn.com/blogs.cornell.edu/dist/d/958/files/2016/10/ShiitakeViabilityWorkbook2018_smallfile-11z0qy6.pdf
• Kentucky Shiitake Production Workbook: Harvesting by Deborah Hill is a free downloadable pdf available at
  ca.uky.edu/agcomm/pubs/for/for85/for85.pdf
• Kentucky Shiitake Production Workbook, Inoculation by Deborah Hill is a free downloadable pdf available at
  ca.uky.edu/agcomm/pubs/for/for81/for81.pdf

For more information, check out woodlandstewards.osu.edu.

Additional Resources

Learn more about the steps to cultivation and considerations for production of shiitake mushrooms:

Baughman, M. (1989). Financial analysis of shiitake mushroom production. Shiitake mushrooms: The proceedings of a national symposium and trade show. University of Minnesota, Educational Development System.

Bratkovich, S. M. (1991). Shiitake mushroom production on small diameter oak logs in Ohio. Proceedings of the 8th Central Hardwood Forest Conference (pp. 543–549). United States Forest Service, Northeastern Forest Experiment Station.
nrs.fs.usda.gov/pubs/gtr/gtr_ne148.pdf

Gilbert, M. (1991). FRC Shiitake mushroom field trials conclude. Shiitake News. 8(3), 1–9.

Hill, D. B., & Szymanski, M. (2010). Kentucky shiitake production workbook, inoculation FOR-81. University of Kentucky Cooperative Extension Service.
ca.uky.edu/agcomm/pubs/for/for81/for81.pdf

Londo, A. J. & Londo, H. A. (2022). Forestry terms for Ohio forest landowners [Fact sheet]. Ohioline.
ohioline.osu.edu/factsheet/f-0104

Mudge, K, Matthews, A., Waterman, B., Hilshey, B., Siergk, S., Laskovski, N., Rockcastle, J., Rockcastle, S., & Gabriel, S. (2013). Best management practices for log-based shiitake cultivation in the Northeastern United States. Northeast Sustainable Agriculture Research & Education.
projects.sare.org/wp-content/uploads/977907shiitake-bmp-3-11-final-for-print-hires.pdf

Royse, D. J., Schisler, L. C., & Diehle, D. A. (1985). Shiitake mushrooms consumption, production and cultivation. Interdisciplinary Science Reviews. 10(4), 329–335.
doi.org/10.1179/isr.1985.10.4.329

Original author (1991): Stephen M. Bratkovich, Former Extension Specialist, Forestry, Ohio State University Extension