Sources of Organic Fertilizers and Amendments
Agronomy Resource Listby Andy Pressman
NCAT Agriculture Specialist
How to Use This Resource List: For your convenience, you can now search for suppliers by state, by product category, or by using a keyword. Before beginning your search, however, you are encouraged to read About This List and What Can I Use in Organic Crop Production.
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About this List
Organic farming is a whole-system approach to optimizing the natural fertility resources of a farm. It works through traditional practices of recycling farm-produced livestock manures, composting, crop rotation, green manuring, and crop residue management. Secondarily, organic agriculture looks to local waste products—manures, food and seafood processing wastes, etc.—to supplement soil fertility economically.
While many organic operations achieve a high degree of sustainability using these methods, innate nutritional deficits in regional soils, past management abuses, and high productivity demands often require the farmer to purchase additional fertilizers or amendments from specialty suppliers.
This resource list is a guide to suppliers of bulk organic fertilizers and specialty soil and foliar amendments, and is geared to commercial farmers and market gardener—especially organic producers. Sources are categorized by product type, and thus it also serves as an educational overview of the different organic fertilizers, biostimulants, inoculants, rock minerals, and other amendments available. The products and suppliers listed are based on the compilers' current knowledge of the materials available in the marketplace and the specific product offerings of each company listed.
Please note that this list focuses on manufacturers, regional and national distributors, and mail-order sources. It is not comprehensive and includes few localized dealers, as these would be too numerous to mention. Therefore, be advised that many of these materials and products can be found locally at farmers' co-ops, retail garden centers, nurseries, neighborhood organic supply outlets, and the like. This is especially true of plant and animal by-products, dried livestock manures, composts, fish emulsion, and seaweed extracts. Take the time to shop carefully Comparing prices and labels can yield significant savings.
It is important for the reader to know that mention of a product does not ensure its acceptability for certified organic production. (See the text box What Can I Use in Organic Crop Production?) Furthermore, many of the companies listed sell a wide range of products including some that are prohibited under the National Organic Standard. It is the responsibility of the grower to consult with his/her certifier and determine the acceptability of any questionable material or product.
Finally, the mention of a company or individual in this list does not constitute an endorsement of that company, its products, or its business practices, by NCAT, the ATTRA Project, or the USDA.
Qualified businesses not presently included in this list should contact Andy Pressman at ATTRA for inclusion in future updates. Updated information should also be addressed to his attention. Contact Andy at:
Qualified organizations not presently included should either use Submit/Update Listings or contact Andy Pressman at ATTRA for inclusion in future updates. Updated information can also be addressed to their attention.
E-mail Andy Pressman
This page was last updated on: May 16, 2012