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Using Approved Farm Inputs and Materials for Organic Certification

UpdatedSeptember 9, 2025
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What To Know About Using Approved Farm Inputs & Materials for Organic Certification

Summary: When farming organically, not all materials are created equal. Fertilizers, pest control, seeds, compost, and even mulch must be approved before use. Using an unapproved input, even by mistake, can risk your organic certification. Oregon Tilth and trusted resources like OMRI can help you determine what\’s allowed. Always get approval first, follow usage restrictions, and document everything in your Organic System Plan (OSP).

Overview: Why Material Approval Matters

For your farm to be certified organic, every input you use whether it’s fertilizer, pest control, or compost— must comply with USDA National Organic Program (NOP) standards. This means you can’t just grab something off the shelf. You must:

Even if a product is labeled “natural” or “organic,” that does not mean it’s automatically allowed in certified organic production.

Materials Allowed During Transition to Organic

During your transition period, only inputs approved for organic use are permitted. These include:

  • Fertilizers
  • Pest and disease controls
  • Seeds and seed treatments
  • Livestock health products
  • Cleaning and sanitation agents
  • Any material applied to land, crops, or animals

Check all materials against the USDA National List and use OMRI or WSDA databases to verify approval. When in doubt, ask your Oregon Tilth certification team before using the material.

Fertilizers in Organic Farming

Soil fertility in organic farming must be maintained or improved through practices that promote soil health. These include:

  • Cover cropping
  • Crop rotation
  • Adding plant or animal materials (like compost or manure)

Can I Use This Fertilizer?

Look at the product’s composition. If it contains synthetic materials not on the National List, it’s not allowed. Be especially cautious with:

  • Chemical fertilizers: Synthetic nitrogen, phosphate (e.g., superphosphate), and potash are prohibited.
  • Ammonia or nitrate-based fertilizers: Most are not allowed.
  • Soluble natural fertilizers: Allowed, but must follow specific restrictions.
  • Lime products: Only mined calcium carbonate and dolomite are allowed. Processed forms like quicklime or slaked lime are prohibited.
  • Fish-based and aquatic products: Often allowed with restrictions check first.
  • Compost: Must meet composting or raw manure rules.

Never use any fertilizer unless it is:

  • OMRI or WSDA listed, or
  • Reviewed and approved by your Oregon Tilth team.

Micronutrients

Micronutrients may be used only when:

  • There’s a documented soil or plant deficiency.
  • A crop’s specific needs are known and documented.

Synthetic forms are allowed only with proper documentation. Submit test results and crop requirements before applying.

Manure Use Guidelines

Manure enriches soil but comes with strict rules, especially for crops meant for human consumption. There are no restrictions for crops NOT meant for humans.

Timing Requirements:

  • 120-day interval: If the edible part of the crop touches the soil.
  • 90-day interval: If it does not.

Additional Requirements:

  • Grazing animals: Same 90/120-day rules apply.
  • Off-farm manure: Must be free of prohibited additives (e.g., bedding with synthetic chemicals). Supplier documentation is required.

Compost Use in Organic Farming

Plant-Based Compost:

  • Allowed with no pre-harvest interval.
  • Feedstocks must be nonsynthetic.
  • Document source and ingredients in your OSP.

Compost Containing Animal Materials:

Two options:

  • Treat as raw manure (apply 90/120 days before harvest).
  • Meet NOP composting standards, which include:
    • 3+ days at 131°F or higher
    • Documentation of time, temperature, ingredients, and pile turnings

Off-Farm Compost:

  • Requires a statement of ingredients, temperatures, and turnings.
  • No documentation? Treat as raw manure.

Mulch & Biodegradable Biobased Mulch Film (BBM)

Approved Mulches:

  • Nonsynthetic: Bark, leaves, straw, etc.
  • Recycled paper: Must be free of glossy or colored inks.
  • Plastic mulch: Allowed if PVC-free; must be removed at season\’s end.
  • Biodegradable biobased mulch (BBM): Rarely allowed. Must meet strict standards for biodegradability, compostability, and be non-GMO.

Note: As of now, Oregon Tilth has not approved any BBM due to current regulatory limitations.

Key Reminders

✅ Always verify materials through:

  • The OMRI Products List
  • WSDA Material Input List
  • Your Oregon Tilth certification team

✅ Include all materials in your Organic System Plan.

✅ Never assume a product is allowed based on its label alone.

✅ Keep records of material use, including:

  • Product labels
  • Purchase receipts
  • Application logs
  • Supplier statements (if off-farm sourced)

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