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.