Using fertilizers

Organic farmers are required to manage soil fertility and crop nutrients in a way that maintains or improves soil organic matter content.

Approved methods include, but are not limited to, crop rotations, cover crops, and the incorporation of plant and animal materials into soil. All fertilizers and soil amendments must be included in your Organic System Plan and approved by OTCO.

How do I know if I can use a fertilizer?

When asking, “Can I use this fertilizer or material?,” focus on the product’s composition. You must follow the same guidelines for materials, observing all approved product restrictions and prohibitions per the National List.

Do not risk jeopardizing your certification — a label may not disclose all of the product’s ingredients. For all non-OMRI or non-WSDA approved materials, request approval from your client service team. Never use an unapproved fertilizer until after OTCO review and receipt of approval.

What chemical fertilizers are prohibited?

All chemical fertilizers — particularly macronutrient nitrogen, phosphate (e.g., triple or super) or potash — as identified on the product composition label are prohibited for use.

Are ammonia and nitrate-based fertilizers prohibited?

All ammonia fertilizers and most nitrate fertilizers are not allowed.

Are soluble natural fertilizers allowed?

All highly soluble natural fertilizers are permitted for use with restrictions.

Is lime permitted for use?

Not all sources of lime are allowed. Mined limestone (calcium carbonate) and dolomite (magnesium carbonate) are permitted for use, while quicklime (calcium oxide), burnt dolomite (magnesium oxide), slaked lime (calcium hydroxide), and milk of magnesia (magnesium hydroxide) are prohibited.

What about fish-based or aquatic products?

Stabilized liquid fish products, aquatic plant extracts and humic acid derivatives are permitted for use with restrictions.

Are there any prohibitions for compost?

Compost made from sewage sludge (human waste/bio-solids) or fortified with synthetic fertilizers is prohibited. Additionally, you must follow compost restrictions and guidelines.