Materials and inputs in organics

#Approved materials

When evaluating which materials — e.g., fertilizers, sanitizers, pest management controls, processing aids, etc. — you might use on your operation, we strongly encourage you to consider assessing options reviewed and approved by the Organic Materials Research Institute (OMRI) and the Washington State Department of Agriculture (WSDA). OTCO allows use of OMRI- and WSDA-approved materials provided they are in current approved standing, and used in accordance with listed restrictions.

Materials are separate from sourcing organic seeds and ingredients, please review those rules separately.


Don’t risk losing or jeopardizing your certification. Never use an OTCO unapproved material — or a non-OMRI/WSDA approved material — until after OTCO review and approval.

Request a list of current, OTCO-approved materials
OTCO is able to provide assistance regarding approved materials for crop, livestock and processing/handling operations. Please note, we’re only able to provide listings for product types and not particular brands. Please contact your client service team for additional info.


Oregon Tilth re-reviews all materials/inputs intended for use in a NOP certified product every five years. As such, we may periodically request that you submit updated documentation to assist us in verifying the continued compliance of the materials you use.

Request approval for an unapproved material

  • Tell us how you want to use it
    In order for our staff to review the material, we need to know how you plan to use it. Keep it simple, but be sure to identify whether the material is for crop, livestock or processing.
  • Provide product information
    OTCO requests the exact full brand name, product type (e.g., 2.0, Plus, granular), manufacturer, copy of product label, ingredient list, and specification sheet.
  • Send information to OTCO
    Our staff will help determine the best way to send your request and information. OTCO will provide a written response of approval or denial upon completion of review.


For more information on materials approval see our Big Questions Answered brochure.

#The National List

The National List of Allowed and Prohibited Substances defines which non-organic substances are allowed and which agricultural substances are prohibited for use in organic crop, livestock, and processed food production.

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