Carbon Dioxide Enrichment of Controlled Environment Plant Chambers via Specialty Mushroom Cultivation

View the project final report

Commodities

• Miscellaneous: mushrooms

Practices

• Crop Production: cropping systems, food product quality/safety, greenhouses
• Education and Training: extension
• Farm Business Management: new enterprise development
• Natural Resources/Environment: carbon sequestration
• Production Systems: greenhouse systems
• Sustainable Communities: sustainability measures, urban agriculture

The past few years have seen the rise of controlled environment ‘vertical farms’ in almost every major city around the world. These precisely controlled plant chambers require a high level of carbon dioxide to maintain optimal photosynthetic levels. Currently, there are two main options to accomplish this – injecting pure C0₂ from cannisters or using a generator that is run on natural gas or propane. Injecting pure C0₂ is a cost-inefficient option while burning natural gas or propane increases the carbon footprint of the vertical farm. As cities trend towards a carbon-free future, alternative sources must be explored for C0₂ enrichment.

This problem can be addressed by linking a specialty mushroom cultivation chamber with a plant cultivation chamber via air exchange. Carbon dioxide respiration from mushrooms can be used to enrich leafy plants that photosynthesize.  If enough carbon dioxide can be generated, this research will shift the paradigm for how growers enrich their plants with carbon dioxide. Furthermore, specialty mushroom cultivation can also play an important role in tackling the problems of local food insecurity, inefficient water use, and waste management by growing highly nutritious mushrooms on agricultural and industrial waste.

This research will focus on which specific species, substrates, and environmental conditions are ideal in the context of urban agriculture. The impacts will be measured by C0₂ levels, yield, and bio-efficiency. Outputs of this research will include a published scientific paper and an instructional guideline in order to empower a new generation of specialty mushroom cultivators.

1. Measure which species of specialty mushrooms produce the highest amount of yield and usable carbon dioxide for plant chambers. The species of specialty mushrooms will be selected based on their market potential, nutritional profile, and demonstrated history of cultivation - Pleurotus ostreatus (Pearl Oyster), Hericium erinaceus (Lion’s Mane), and Lentinula edodes (Shiitake). The timeline of mycelial inoculation of the substrate bags to post-harvest is approximately six weeks – therefore, the project will be able to go through multiple rounds of testing within a one-year time period.
2. Measure which substrate produces the highest amount of bio-efficiency and usable carbon dioxide for plant chambers. The substrate is a critical variable in terms of efficient mushroom production and may have a profound impact on the amount of carbon dioxide emitted by the mushroom for enrichment of plant chambers. The substrate can be divided into a carbon source and the nitrogen source. Whenever possible, this project aims to partner with local businesses for straw, coffee grounds, wood chippings, and other waste streams that can be used as substrate.
3. Measure which controlled environment conditions are optimal for specialty mushroom production (humidity, temperature, ventilation, light, carbon dioxide level). It is important to know the precise conditions that the mushroom grow bags require during the different stages of cultivation. This project will test preexisting assumptions of ideal conditions for growth and see if any controlled changes in environmental conditions may result in higher yield or more carbon dioxide production.