Organic fertilizers are fertilizers that are naturally produced. Fertilizers are materials that can be added to soil or plants, in order to provide nutrients and sustain growth. Typical organic fertilizers include all animal waste including meat processing waste, manure, slurry, and guano; plus plant based fertilizers such as compost; and biosolids. Inorganic "organic fertilizers" include minerals and ash. The organic-mess refers to the Principles of Organic Agriculture, which determines whether a fertilizer can be used for commercial organic agriculture, not whether the fertilizer consists of organic compounds. Examples and sources The main organic fertilizers are, peat, animal wastes, plant wastes from agriculture, and treated sewage sludge. Minerals Minerals can be mined from fossil products of animal activity, such as greensand (anaerobic marine deposits), some limestones (fossil shell deposits), and some rock phosphates (fossil guano). Adding limestone or “liming” a soil is a way to raise pH. By raising the pH of a soil, microbial growth can be stimulated, which in turn...