Increased environmental concerns surrounding soluble nitrogen sources have forced many to reconsider organic fertilizers. Organic fertilizers, as well as slow-release synthetic sources, release small amounts of nitrogen over long periods. University research from across the country has concluded that when applied correctly, organic and slow-release products will reduce environmental impact. Several organic fertilizers are available today. Most are plant and animal by-products, rock powders, inoculants, and conditioners. These products are often sold at garden centers and through horticultural supply companies. This publication will talk about common organic products and how they are released in the soil.