Alternative growing practices for oyster mushroom cultivation in the Northeast

View the project final report

• 2015 annual report

Commodities

• Miscellaneous: mushrooms

Practices

• Crop Production: double cropping, greenhouses, high tunnels or hoop houses, low tunnels, season extension
• Education and Training: networking, on-farm/ranch research, workshop
• Production Systems: organic agriculture, permaculture

This study addresses alternative growing practices for oyster mushroom cultivation in the northeast. Specifically, this study will focus on the method that is used to prepare straw for oyster colonization. Oyster mushrooms are said to “demand few environmental controls, their fruiting bodies are not often attacked by diseases and pests, and they can be cultivated in a simple and economic way”. When compared to other specialty mushrooms these factors along with the short cropping cycle, about 2 months, make oyster mushrooms the most appealing gourmet mushroom to cultivate in the northeast. Most oyster mushroom farms in the northeast, according to mushroomcompany.com there are about 85, use hot water pasteurization to treat straw. Hot water pasteurization requires a large supply of propane (a non-renewable energy source) and constant monitoring by the farmer. This task generally takes 4-8 hours. The farmer must be focused on bringing the water up to temperature, maintaining temperature, and finally removing straw from the 150 degree water.

Working around 140-150 degree water and pulling straw out of a large heated container is difficult and dangerous for mushroom farmers and unappealing to potential mushroom farmers. An alternative method to prepare straw for oyster colonization would offer a demonstrable improvement to new and existing oyster mushroom cultivators.

• This study will give mushroom farmers clear information comparing the different methods of preparing straw for oyster mushroom cultivation. This will result in greater yields and reduced growing costs.


• A change in straw preparation will increase safety for both the workers and the environment. Farmers will no longer need to work around scalding water. The herbicidal effect of dumping near boiling water on the ground will also be eliminated.


• This study will encourage other farmers in the northeast to begin cultivating oyster mushrooms. The Commercial Mushroom Growers Network has shown the diverse methods farmers use to prepare straw but there remains a lack of data studying the benefits and downfalls of each method in the northeast. Several farms have moved towards more sustainable methods including cold fermentation and lime treatment instead of the traditional hot water pasteurization. This study will look deeper into these methods and compare the time taken to prepare the straw and biological efficiency (BE) for four different techniques.

In a preliminary survey of two groups, the Commercial Mushrooms Growers Network and the Mushroom Listserv (Cornell) Fungi Ally received positive feedback to conduct this study. Of the ten responses received eight of the farmers had tried different techniques of treating straw but were continuing use of hot water pasteurization. When asked if a study comparing B.E. for different straw preparations would be valuable nine of the ten farmers responded with a five (the highest on a scale of one-five). One responded with a four. Two of the farmers had been injured or burned while doing hot water pasteurization and another farmer would not allow his employees to do this process because of the risk.

Fungi Ally proposes the use of cold fermentation or wood ash soak to treat straw for oyster mushroom cultivation. These two treatments are safer, less expensive, less time consuming, and more attractive to potential oyster mushroom farmers than hot water pasteurization. We will measure Biological Efficiency and time of preparation for four different treatment methods to discern which is best:

Pasteurization - Hydrated lime soak - Cold fermentation - Wood ash soak.

There are three objectives for this project:

• Quantify the most effective treatment method for straw used in oyster mushroom cultivation for small-scale mushroom farms in the Northeast.


• Record how different strains of oyster mushrooms respond to the different pasteurization techniques.


• Publish and distribute a guide for oyster mushroom cultivation in the northeast. This guide will include straw preparation methods, spawn sources, incubation and fruiting guidelines, building a fruiting room, storage of oyster mushrooms, and marketing.

Fungi Ally will be measuring Biological Efficiency (B.E.) and time of preparation between four different straw treatment methods and six different strains from May 1^st through October 31^st. We will exclusively use grain spawn for all inoculations and inoculate at 10% of wet weight of the substrate. All straw will be chopped in a leaf mulcher before being treated. We will inoculate, incubate, and harvest 2 different strains during each trial. Each treatment method will fill 16 bags total, 8 of each strain. Straw will be treated by one of the following four methods.

• Hot water pasteurization. This will be the control for each trial run. Straw will be submerged in a 55 gallon barrel of water. The water will be brought to 150 degrees F and maintained for 2 hours. The straw will then be removed


• Hydrated lime soak. Water will be mixed with the proper amount of hydrated lime to bring the solution to a pH of 12, approximately 2 cups. The water will then be pumped to a showerhead and sprayed onto the straw in a 55 gallon drum for 16 hours, with a minimal amount of water left over.


• Cold fermentation. Straw will be submerged in a 55 gallon barrel of water for 5-8 days. Straw will be removed when the smell of fermentation is apparent.


• Wood ash soak. Water will be mixed with the proper amount of wood ash to bring the solution to a pH of 12, approximately 12 cups. The water will be pumped to a showerhead and sprayed onto the straw in a 55 gallon drum for 16 hours, with a minimal amount of water left over.

All treatments of straw will be handled the same post treatment. After treatment straw will be laid out on a metal table to cool/drain. Once drained to the proper moisture content, 60%, and cool enough to handle the straw will be packed into plastic tubes. Plastic tubing with a diameter of 10 inches will be used. Each tube will be about 2.5 feet high and weigh 20 pounds. The exact final weight at time of inoculation will be recorded. Straw will be stuffed into the bottom of the tube and layered with grain spawn. The tube will be filled following the layering method of straw, spawn, straw, spawn, straw etc. Each tube will receive 2 lbs of grain spawn. Once full the tubes will be tied off and holes will be punched in the tubes. A spacing of 6 inches in row and 3 inches between rows will be used.

Inoculated tubes will incubate for 3 weeks until full colonization occurs.

• Fully colonized tubes will be moved into the fruiting room and monitored by the project manager.


• Humidity and air exchanges will be maintained at proper levels for mushrooms to develop properly.


• High and low temperature and humidity levels will be recorded daily.


• First harvest will occur within 1-2 weeks of moving the tubes into the fruiting room. The wet weight of mushrooms will be recorded for each tube.


• A second flush will be allowed to form within the next 2 weeks and the wet weight will again be recorded.


• After 4 weeks bags will be removed from the fruiting room and composted. The first flush, second flush, and total B.E. will be measured and recorded. The formula to measure B.E. is: B.E.= (fresh weight of mushrooms/ dry weight of substrate) * 100. (Change et al 1981).

The trial will be conducted 3 times between April 13^th and Sept 28^th with inoculations happening the first Monday of the month. There will be a rotation of 6 strains tested throughout the year.

Trials comparing strains will be completed three times during the growing season from April 1 to September 26. The start dates are shown in the table below. Any hours accrued before notification of grant acceptance will not be billed towards the grant.

The labor and data collection for each trial will take approximately 119 hours each.

• 18 hours total for inoculum preparation add 10 hrs for second G2 and third batch. Dylan




• 3 hrs for agar medium preparation, autoclaving culturing


• 5 hrs for G1 prep, autoclaving, culturing


• 5 hrs for G2 prep, autoclaving, culturing    


• 5 hrs for G1 and G2 shaking, monitoring


• 2 hrs for jar washing

• 26.5 hours total for straw prep and inoculation done by Willie




• 2 hrs shredding straw


• 0.5 hrs prep time for cold fermentation


• 1 hr prep time for lime


• 2 hrs prep and cook time for pasteurization


• 1 hr prep time for wood ash


• 18 hrs time inoculation, 2 hrs prep while straw drains, 16 hrs tube creation (32 tubes at 30 minutes per tube) Willie and Dylan

• 11 hrs total for incubation monitoring (1 hr every other day for 3 weeks scoring for progression, contamination) Dylan


• 81.5 hrs total for fruiting set up, monitioring, data collection, and harvesting. Willie and Dylan




• 2.5 hrs for set up


• 56 hrs monitoring, harvesting, data collecting


• 3 hrs breakdown and composting

Written data will be entered into spreadsheets weekly as it is

collected. Setting up the sheets will take 2 hrs, and weekly data entry will take 1 hr. Data Analysis be performed starting October 5 after all data has been collected. Calculating B.E. values and creating charts will take 5 hrs.

-6hrs for presentation

-20 hrs for booklet

-Presenting 10 hrs

-travel

During straw colonization, photographs will be used for documentation of colonization and contamination data, and will be used to demonstrated any notable differences in mushroom quality. In addition, B.E. will be calculated as mentioned above. Any significant differences between preparation times between treatments will be noted.

Research results will be shared with mushroom farmers through multiple channels:

• Fungi Ally will apply to speak at several conferences including the 2015 NOFA summer conference, the 2016 Telluride Mushroom Festival, and the 2015 Radical Mycology Convergence. All three events are attended and seen by hundreds of people with elevated interest in oyster mushroom cultivation.


• Fungi Ally will publish this study and information on straw preparation, spawn sources, strain selection, and fruiting requirements in the winter of 2015-16. We will share this guide on our website, in the Commercial Mushroom Growers Network, the Mushroom Listserv, The Mushroom Growers Newsletter and with our contact list of over 200 mushroom cultivators who have attended our workshops.


• In the fall of 2015 we will have an on farm tour and demonstration of our research open to the public. We will advertise this event through CISA, our website, Facebook page, email list, NOFA mass, Stockbridge School of Agriculture, and mushroomcompany.com.