Oregon State University has developed a tool to help growers compare the cost, nutrient value, and nitrogen availability of organic fertilizers.
The Organic Fertilizer Calculator is an online Excel-based calculator designed to help farmers compare organic fertilizers and plan the most balanced and cost-effective fertilizer program for their farm. Growers first use a worksheet to check the nutrient analyses of the materials being evaluated and then enter application rates to determine total nutrients provided. The costs worksheet helps growers compare product prices.
To download or learn more about the calculator, visit http://smallfarms.oregonstate.edu/organic-fertilizer-calculator.
Editor’s note: The original link above from when this was published no longer works. Oregon State University has created a new page at: https://extension.oregonstate.edu/organic-fertilizer-cover-crop-calculators