Fact sheet that provides guidelines for using mulches and weed barrers in organic production
Guidelines for Using
Mulches and Weed Barriers
O rg a n i c C e rt i f i c a t i o n F a c t S h e e t
WSDA Organic Program has developed guidelines to help producers understand organic
standards as they relate to the use of mulches and weed barriers. USDA organic regulations define
mulch as any material that serves to suppress weed growth, moderate soil temperature, or
conserve soil moisture.
USDA organic regulations require producers to use management practices to prevent crop pests, weeds, and diseases. Weed problems may be
controlled through mulching with fully biodegradable materials, or by using plastic or
other synthetic mulches: Provided that, they are removed from the field at the end of
the growing or harvest season. 7CFR §205.206
Mulches and weed barriers are production inputs on organic farms. All mulches and weed barriers,
synthetic or non-synthetic, must be included in your annual Materials Inventory.
Acceptable Mulches and Weed Barriers
Non-Synthetic Mulches
Non-synthetic mulches and weed barriers are acceptable for use in organic production. Some of
the most commonly used non-synthetic mulching materials are manures, bark chips, sawdust,
leaves, grass or flower cuttings, hedge trimmings, and straw. Request and maintain records
regarding the source and content of any inputs to ensure they don’t contain prohibited materials.
Synthetic Mulches
Acceptable synthetic mulches include biodegradable paper mulches from recycled sources (ex.
black-and-white sections of newspapers), as well as plastic mulches, weed barrier fabrics, or row
covers. Synthetic biodegradable mulches must meet specific standards to be acceptable.
In annual cropping systems, plastic mulch, weed barriers, or row covers must be removed after the
crop is harvested. In perennial cropping systems, plastic mulch, weed barriers or
row covers may be left in the field beyond the harvest season; however, these
inputs must be removed before the plastic decomposes or breaks into pieces so
that it is not possible to effectively remove all pieces from the soil.
AGR 3007 – Updated July 2019
Guidelines for Using Mulches and Weed Barriers
Page 2
Biodegradable mulch film products must be produced without GMOs or feedstocks. Additionally,
they must meet specific criteria for compostability, biodegradation, and bio-based content as
defined at §205.2. As of the printing of this publication, no biodegradable film products have been
approved for use in organic agriculture. Contact WSDA Organic Program prior to the use of these
materials.
Unacceptable Mulches and Weed Barriers
Newspaper or other recycled paper with glossy or colored ink.
Polyvinyl chloride (PVC)
Biodegradable mulch film that does not meet the required standards
Additional Resources
Biodegradable Biobased Mulch Film Definition: USDA Organic Regulations §205.2
https://www.ams.usda.gov/rules-regulations/organic
NOP Guidance: Allowance of Green Waste in Organic Production Systems (NOP 5016)
https://www.ams.usda.gov/content/usda-address-green-waste-compost-ruling
Cooperative Extension: Mulching for Weed Management in Organic Vegetable Production
http://www.extension.org/pages/62033/mulching-for-weed-management-in-organic-vegetableproduction
WSDA Organic Program
PO Box 42560 | Olympia WA 98504-2560
(360) 902-1805 | organic@agr.wa.gov
http://agr.wa.gov/organic
AGR 3007 – Updated July 2019
All Regions
External Link
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