Spent Mushroom Substrate as Fertilizer

View the project final report

• 2015 annual report
• 2016 annual report

Commodities

• Agronomic: rye, wheat
• Vegetables: beans, beets, garlic, greens (leafy), peas (culinary), peppers, radishes (culinary), tomatoes
• Additional Plants: herbs
• Miscellaneous: mushrooms

Practices

• Crop Production: drought tolerance, fertilizers, organic fertilizers
• Farm Business Management: community-supported agriculture
• Soil Management: organic matter

Nebraska Mushroom, in partnership with Cook Grow Sew and Red Hawk Farms, will explore environmental and economic benefits of utilizing spent mushroom substrate as a crop-enhancing soil amendment. The project will conduct studies comparing soil health and produce/income outcomes. Established relationships with CSAs and Community CROPS will be the outreach conduit. (50)

Currently Nebraska Mushroom produces 100 pounds of mushrooms each week, along with 1600 pounds of spent substrate with plans to double capacity and output in the next 3 months. Currently this waste is discarded in landfills and will equal over 83 tons of waste in 2015. With the rich nutrient (Nitrogen, Phosphorus, and Potassium) and moisture retention value, spent mushroom substrate is a soil amendment for organic crops. It is essential for Nebraska Mushroom to reduce landfill contributions and costs while generating a revenue stream through dissemination of the spent substrate to farmers to be put to use as fertilizer. This mutually beneficial relationship will allow vegetable farms to utilize a locally produced and available organic fertilizer at a lower cost than what is currently being used. Some farmers are using higher cost products produced out of state and/or from multiple sources whereas this all-inclusive compost promotes healthy, diverse soil structure, which is a naturally balanced growing medium that helps defend against pathogens and insect infestations. Increased production is anticipated from this study as well, which translates into increased income to local farmers. Some studies have indicated that use of spent mushroom substrate improves appearance and increases size and weight of produce.

Currently local farmers utilize multiple products on their crops. This study will explore the cost benefit of using substrate and viable pricing structure in relation to other methods.

Nebraska Mushroom's substrate consists of shredded organic matter, including hardwood sawdust, hardwood chips, rye, wheat bran, lime, gypsum, water, and wheat straw. The bran, rye, lime, and gypsum are typically used up in the growing process, however, there may be trace amounts. Once weathered, the microbes are active and create an end product that is partially decomposed hardwood. This ideal growing medium for mushrooms has many benefits for other organic crops including acting as pesticide and fertilizer.