Using mulches and biodegradable biobased mulch film
In farm crop production, you can use mulches — bark, leaves, hay, newspaper — under specific conditions and restrictions.
All mulches and crop inputs must be included in your Organic System Plan and approved by OTCO prior to being used for any purpose on certified land.
What types of mulch are allowed for use in organic crop production?
Nonsynthetic mulches (i.e. bark, leaves, hay) are allowed for any application in organic crop production and may be used as a fertilizer, pesticide, general crop tool or production aid.
Synthetic mulches are prohibited, except for three types approved for use in organic agriculture:
- Newspaper or other recycled paper, without glossy or colored inks
- Plastic mulch and covers (petroleum-based, PVC-free)
- Biodegradable biobased mulch (BBM) produced without organisms or feedstock derived from excluded methods (non-GMO)
Allowed synthetic mulches must comply with all organic regulations that limit how the mulch is produced and used in organic application.
Can I use newspaper and recycled paper as mulch?
Can I use plastic as a mulch?
Plastic mulch that does not contain polyvinyl chloride (PVC-free) may be used in organic crop production as an herbicide or a weed barrier only and must be removed at the end of the season.
Plastic mulches used in perennial crop applications may be left for more than one season as long as it’s removed before the plastic decomposes, breaks into pieces, or becomes impossible to effectively remove from the soil. Plastic mulches that biodegrade or break down are not allowed since removal at the end of the season is required.
Can I use a biodegradable biobased mulch film (BBM) as a mulch?
There are very few BBM approved for use in organic production. Before using any BBM, you must request approval from your organic certifier to review for compliance and verify whether it meets the following regulatory requirements:
- Compostability standards ASTM D6400, ASTM D6868, EN 13432, EN 14995, or ISO 17088
- At least 90% biodegradation absolute or relative to microcrystalline cellulose in less than two years in soil, according to one of the following test methods: ISO 17556 or ASTM D5988
- Must be biobased with content determined using ASTM D6866, 7 CFR 205.3
Although multiple submissions for BBM approval have been received, Oregon Tilth has yet to approve any BBM for organic crop production due to the inability to meet regulations.
Can the BBM regulatory requirements change in the future?
The National Organic Standards Board (NOSB) considered revising the definition and requirements for BBM at the Fall 2020 NOSB Meeting.
Both industry representatives and certification bodies commented that current BBM regulations result in very few approvals. Regrettably, other less environmentally friendly plastics with harsher impacts on the planet are approved and used.
Oregon Tilth encourages stakeholders and interested parties impacted by current BBM regulations and policies to submit comments and opinions to the NOSB and to the NOP. Help regulators understand the detrimental impacts of current legislation and the organic industry’s desire to modify regulations to provide a more environmentally friendly, usable alternative.
- Oregon Tilth’s Comments to the NOSB, Spring 2020: Biodegradable Biobased Mulch Film
- Allowed Mulches on Organic Farms and the Future of Biodegradable Mulch
- 2012 Technical Report: Biodegradable Mulch Film Made from Bioplastics
- 2015 OMRI Report on Biodegradable Mulch
- 2016 Supplemental Biodegradable Biobased Mulch Film Technical Report
- NOP Memo to the NOSB with Report on Biodegradable Biobased Mulch Films in Organic Crop Production (Michigan State University (MSU, September 2019) (pdf)
- NOSB Research Priorities for 2020
- NOSB Meeting: October 2020 – Discussion documents and outcomes
- NOSB Meeting: April 2021 – Check here for upcoming discussion documents