Investigating the Efficacy of Reusable Grow Bags in Specialty Mushroom Cultivation to Reduce Single-Use Plastic

Commodities

• Miscellaneous: mushrooms

Practices

• Crop Production: municipal wastes
• Education and Training: farmer to farmer
• Sustainable Communities: infrastructure analysis

Mushroom cultivation generates
roughly 1-2 million tons of polypropylene (PP) and high-density
polyethylene (HDPE) plastic waste per year globally, with 3 tons
of plastic coming from Bridgetown Mushrooms alone. A reusable
alternative to single-use plastic grow bags would significantly
reduce plastic waste. This project will test the feasibility of a
reusable grow bag made of silicone rubber (SR) and compare
growing outcomes with current single-use PP bags.

Previously, Bridgetown Mushrooms
partnered with the Oregon Applied Sustainability Experience,
funded by US EPA, to investigate effective alternatives to PP
bags. Solutions explored had significantly lower production
rates, higher costs, or infrastructure requirements infeasible
for the company. The company distributed an industry survey and
interviewed nine experts, all of which expressed concern about
plastic waste in the industry. Findings concluded that while
there is not a simple solution, there is collective desire to
reduce waste and explore reusable bags. 

SR stands out as a potentially
suitable material for reusable bags. SR can be used indefinitely
at 300°F with minimal deterioration. This project seeks to test
an initial concept of a reusable bag made of SR to determine its
viability. Working with material specialists, Bridgetown
Mushrooms will develop and compare a reusable bag made of SR with
the current standard PP bag. Lessons learned from this project
could pave the way for eliminating the majority of plastic waste
in the industry. Potential outcomes would be the elimination of
at least 78,000 single-use plastic bags (3 tons) per year at
Bridgetown Mushrooms alone, and collaboration with the industry
for broader development and adoption.

Bridgetown Mushrooms will develop
a fact sheet and accompanying graphics to distribute via its
social media channels and website, will share information at an
industry conference, and will initiate a pledge for cultivators
to reduce plastic waste in the mushroom industry.

Research Objectives:

1. Assess the difference in biological efficiency between
   fruiting blocks cultivated in reusable silicone rubber (SR) bags
   and standard polypropylene (PP) bags.
2. Evaluate the variance in contamination levels for the
   treatment (SR) and the control (PP).
3. Determine the longevity of prototype reusable SR bags when
   subjected to continual heat exposure in an autoclave.
4. Establish the financial cost and feasibility of adopting
   reusable silicone bags.

Educational Objectives:

1. Raise awareness and promote reusable growing bags to
   professional mushroom cultivators and hobbyists.
2. Engage with stakeholders and build community support for
   alternatives to single-use plastic growing bags.
3. Introduce a pledge for cultivators to reduce plastic waste in
   the mushroom industry.