More About Mushroom Sustainability

Mushroom growers are ultimate recyclers, taking waste from other sectors of the agriculture industry and composting it into substrate, which is what mushroom farmers call the organic matter mushrooms grow in.

  • A big part of the mushroom composting process is combining used straw and bedding materials from horse farms as the recipe for mushroom substrate. It is also common for mushroom growers to recycle mushroom stumps from harvesting as compost ingredient for the next crop.
  • Other recycled materials used as part of the compost recipe for mushroom substrate include chicken litter (bedding litter that can be used as a fertilizer) from poultry farms, cotton hulls (what is left of cotton bolls when the fiber has been harvested), almond husks, corn cobs, brewers grain (left over when processing grains to make beer and other malt products), wheat straw, molasses, saw dust, and other similar materials that are left over from the processing of food, fiber, and fuel materials.
  • The recipe for mushroom substrate is just as important – and just as customized by farmer – as the recipes we use in our kitchens. Growing mushrooms can be tricky and highly specialized. The substrate for mushrooms grown in Pennsylvania may be a little bit different than that used to grow mushrooms in California or Texas because of each area’s differences in what is available locally. Taking advantage of the products of other agricultural enterprises where mushrooms are grown is part of what makes mushrooms so sustainable – and what makes the mushroom industry a perfect partner for other agricultural operations.

Growing mushrooms is a mystery to most people. Because of how they are grown (in indoor growing houses), you don’t see them out in fields or go pick them yourself. But this growing process is just part of what makes mushrooms one of the most sustainable foods on the planet.

  • Mushrooms produce high yields from a very small physical footprint. In 2017-18, 26 million square feet (or about 1 square mile) of growing area produced the 891 million pounds of mushrooms sold in the U.S.
    • Mushrooms are grown indoors in facilities called “mushroom houses.” In more traditional facilities, the exterior is concrete with layers of wooden beds where the mushrooms are grown.
    • Newer operations may be constructed of more energy-efficient materials and feature additional vertical growing space on aluminum beds and automation.
    • In many of the growing houses, temperature, humidity, and fresh air can be managed remotely/automatically – sometimes through an app on the owners’ smart phone!
  • The growth cycle of a mushroom crop in the growing room is just 6-10 weeks, so each mushroom farm can produce as many as 8 crops per year. This rapid growth cycle means facilities are consistently in use, and some inputs are durable items that are cleaned and re-used for each crop.
    • Mushroom beds are typically harvested in breaks or flushes, staggered about a week apart, with 3-4 days of harvesting for each flush. Being able to get multiple harvests from each crop is another way in which mushrooms are a relatively low input, highly sustainable food.   
  • Following harvest, the substrate that produced the mushrooms is a great byproduct that has multiple uses. These include mine reclamation projects, green roofs, landscaping and home gardening (including potting soil), application on field or vegetable crops and various forms of re-use within the mushroom industry.
    • Given the ways that mushroom compost can be used after the crop is done, and the ability of the farmers to re-use water within the operation, mushroom farms generate very little waste.

From an environmental perspective, mushrooms farmers are progressive stewards of the land, water, soil, and air.

  • Because mushrooms are grown indoors, managing inputs – including energy and water consumption – is very important for mushroom growers. Being smart about how they use and re-use materials is helpful from an environmental standpoint and as part of managing their overall business.
    • Many in the mushroom industry, from those who are composting materials to create mushroom substrate to the growers themselves who operate the farms, reuse water to make sure this very valuable resource is managed and reused as effectively as possible – and that local water supplies are protected and preserved.
    • Mushroom farms are finding ways to manage their energy use, which includes using building space and grounds to create their own power sources. One farm in Pennsylvania has installed solar panels and is able to source the energy needed to grow mushrooms from the sun!
    • Mushroom farms are also able to manage their operations in a way that means they are consuming energy during ‘off peak hours’ – early in the morning, late in the evening or even overnight. This decreases the demand on the energy grid, resulting in smarter energy use across the community the mushroom farm is in.
  • Mushroom Farm Environmental Management Plans (MFEMP) from the Pennsylvania Department of Environmental Protection provide growers with guidance on how to manage the environmental footprint of mushroom production. Farms in other states have also adopted these guidelines. This is an important part of the sustainability process that encompasses waste management, soil management, groundwater, air, and even facility management best practices aimed at making mushroom growers good neighbors and environmentally aware stewards of natural resources.
  • Another sustainable approach to growing mushrooms is the use of Integrated Pest Management or IPM plans. IPM is an ecological approach to managing pests. Because mushrooms can grow so well in small areas, it is critical that pests and diseases be managed using effective, sustainable ways. An IPM program means farmers are thinking about how they are growing mushrooms and how to prevent pests and diseases – as well as how to treat them.
    • Rather than spraying chemicals to eliminate threats (like pests and diseases), an IPM approach has growers think about their facilities, the inputs they are using, how they are growing mushrooms (the length of the growing cycles), the tools their employees are using (picking baskets, cutting knives, etc.), sanitation, and even the use of beneficial insects to control those that are harmful to the mushrooms.
    • IPM is a holistic way to looking at how mushrooms are grown, and a major part of the sustainability of an industry that grows more than 900 million pounds of mushrooms on a relatively few farms.

Technology is also playing a role in helping mushroom farmers decrease inputs and increase sustainability through energy use strategies, such as automated operations and new tools that help monitor and decrease inputs, including lights, moisture, and temperature. Mushroom farmers are also using technology to manage the process of filling/emptying mushroom beds and move product from farm to consumer.  

Mushroom farms are an economic driver in their communities. A great example of this is Kennett Square, PA (Chester County), which is known as the “Mushroom Capital of the World,” and is home to 47 Agaricus mushroom growers.

  • Pennsylvania accounts for 63% of the fresh mushrooms grown in the U.S., creating adirect economic impact of $793 million per year. When you add in industries that are related to growing and processing mushrooms, there is a total economic impact of $1.1 billion per year and 8,600 jobs (with $298 million going toward employee compensation). For the Commonwealth of Pennsylvania, this means total annual tax revenue from the mushroom industry of $17 million.
  • Nationally, growing and processing mushrooms is a $1.5 billion industry with a total annual economic impact of $3.1 billion. There are 20,800 jobs in the mushroom industry, generating $853 million per year toward employee compensation. 

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