D.I.Y. FunGuide: Grow Your Own Oyster Mushrooms at Home (2024)

Basic Materials for Path 2

Three main components are required to start oyster mushroom cultivation:

• Healthy, vigorous spawn
• Pasteurized lignocellulose substrate
• Containers, such as plastic bags (Figure 1)

Protocol

(A) Spawn

For home cultivation, short of buying a ready-made kit, the fastest and simplest approach to growing oyster mushrooms is to purchase spawn rather than produce it. There are many commercial producers of oyster mushroom spawn. Examples are listed in Appendix A.

(B) Lignocellulose Substrate

Using Straw as a Substrate for Oyster Mushroom Cultivation

Wheat straw is an excellent lignocellulose substrate to grow oyster mushrooms on. But one can use many other substrates, including rice stalks, corn cobs, coffee grounds, cotton pulp, peanut shells, some plant leaves (such as banana and plantain), and paper.

The lignocellulose substrate provides the food (organic carbon for energy, nutrients) for oyster mushrooms to grow on, supporting buildup of vegetative biomass which then allows production of the mushroom fruiting bodies.

(C) The Protocol for Using Wheat Straw for Oyster Mushroom Cultivation

Step 1. Obtain straw and cut the straw into 4- to 5-inch-long pieces and then soak the straw overnight in water (Figure 2A and 2B).

Step 2. Pasteurization. Drain the excess water, then pasteurize the straw by keeping it at 165 °F in a water bath for 1–2 hrs (Figure 2C and 2D). Alternative methods to pasteurize the straw including using steam or a chemical bath in hydrated lime, but these methods will not be discussed here.

Step 3. Drain the excess water from boiled, sterilized straw for an hour. From Step 3 to Step 8, set up the working space in a clean environment to prevent the contamination (i.e., clean the working desk and room). It is important to inoculate the straw as soon as it has drained and cooled to reduce the risk of colonization by undesirable fungi.

Step 4. Inoculation. Inoculate the pasteurized straw by adding and mixing the spawn with this substrate at a rate of 5–10% volume/volume or weight/weight basis. The inoculation process can be accomplished by bulk inoculation and then filling the plastic bags, or by adding the straw and spawn in alternating layers directly into the bags. A suitable bag size is 25–30 cm by 50–60 cm (10–12'' by 20–24'').

Step 5. Tightly stuff each bag with inoculated substrate, leaving no big gaps inside. The bag should feel like a firm pillow. Close the bags and secure the tops with string or staples. Then carefully make small cuts (cross cuts of 1/2 cm [1/4"]) using a clean, sharp-pointed cutting tool such as a razor blade or trilobate arrow hood. Make about 10–15 holes about 4–6" apart in two whorls a few inches down from the top and a few inches up from the bottom of the bag.

Step 6. Spawn Run. Incubate the filled bags inside a clean, dark place with high relative humidity. Raise the bags above the floor by placing them on concrete or wooden blocks, or they can be hung inside a small dark room at 24–25°C (75–77°F) and high relative humidity (80–90%). An alternative incubation space can be created using a cardboard box or by inverting a large plastic bin over the bags and keeping a good moisture supply from wet cloth towels or cups of water placed underneath (Figure 3). Under proper incubation, white mycelium of the oyster mushroom will grow out from the spawn particles and colonize the straw substrate (Figure 4).

Step 7. Spawn Run, continued. Observe the fungal growth (spawn run) colonizing the straw substrate for the next two to three weeks until the whole bag becomes white indicating good fungal biomass production. The bags are then ready for fruiting, which is triggered by light and lower temperatures (Figures 5 and 6).

Step 8. Fruiting―Mushroom Production. Initiation of the fruiting phase of many oyster mushrooms requires a lower temperature of 20°C (68°F) and light. The completely colonized straw bags can be triggered into fruiting by transfer to a fruiting chamber. This chamber has ambient environment of about 20°C (68°F), controlled (if possible) by an air-conditioning system, 90% humidity controlled by humidifiers or foggers, and a cold source of illumination such as inflorescence or energy-saving light for periods similar to day and night interval (or it could be continuous for the whole fruiting period). In cases where the biomass buildup chamber is going to be used as fruit phase, then the ambient environment condition can be adjusted for that chamber keeping the colonized bag logs in place. Also, there should be good air exchange to avoid carbon dioxide buildup, yet it should not adversely affect or prevent maintaining high humidity (90%) around the bags. An example of a fruiting chamber made using a laundry hamper is shown in Figure 7. Mushroom primordial appear at the holes made in the plastic bags and develop into the "pinhead" stage. The pinheads expand into the first flush of oyster mushrooms if proper air exchange and humidity are maintained (Figure 8). Clusters of the developed mushroom are harvested by twisting and gently pulling or by cutting flush with the substrate with a knife. After this first flush of mushrooms, there should be 2–4 more flushes depending on the fungal strain and the ambient environment.

Note: Protect the bags from crawling and flying insects and rodents. Closely examine the bags for the presence of blue, green, black, or yellow spots, which are indications of contamination and presence of unwanted fungi and/or bacteria. For example, Trichoderma is one of the common contaminants and characterized by rapid greenish growth. Generally, contaminated bags, especially highly contaminated ones, are best removed and discarded. However, partially contaminated bags may yield at least one flush of oyster mushrooms.

Appendix A

Examples of sources to obtain oyster mushroom spawn or oyster mushroom growing kits. There are many others.

1. Amazon
2. Farmers markets
3. Wal-Mart
4. Field and Forest Products (http://www.fieldforest.net)
5. Cascadia mushrooms (http://cascadiamushrooms.com)
6. Fungi Ally (http://fungially.com)
7. Fungi Perfecti (http://www.fungi.com/)
8. Mushroom Mountain (https://mushroommountain.com)
9. Mushroompeople (https://www.mushroompeople.com)
10. Mushroom Adventures (http://www.mushroomadventures.com)
11. Unicorn Bags (https://unicornbags.com)
12. Spore Trading Post (http://www.sporetradingpost.com)
13. Everything Mushroom (http://everythingmushrooms.com)
14. MycoSupply (https://www.mycosupply.com)
15. Wylie Mycologicals (http://www.midwestgrowkits.com)
16. Mushroom Shack (http://www.mushroomshack.com)

Appendix B: References Cited

Kuo, M. 2005. "Pleurotus ostreatus: The oyster mushroom." Retrieved from the http://www.mushroomexpert.com/pleurotus_ostreatus.html

Petersen, R. H. and I. Krisai-Greilhuber. 1996. "An epitype specimen for Pleurotus ostreatus." Mycol. Res. 100:229–238.

Stamets, P. 2000. Growing Gourmet and Medicinal Mushrooms. 3^rd Ed. Berkeley, California: Ten Speed Press.

Vilgalys, R. 1997. "Biodiversity of the oyster mushroom Pleurotus." Mushroom News 1997: 32–35.