Definition
According to the University of California Agriculture and Natural Resources, organic fertilizers " are derived from either plant or animal products containing a significant quantity of one or more of the primary nutrients necessary for plant growth: nitrogen, phosphorus, and potassium. Nutrient content must be labeled on the package. Most natural organic fertilizers also provide significant quantities of organic matter, so they can also be classified as soil amendments." Examples of organic fertilizers include: manures, bone meal, and sludge.
Because organic fertilizers come from natural resources, they are more easily renweable than their synthetic counterparts. They also tend to maintain soil health and promote biodiversity; however, they tend to have lower quantities of nitrogen, phosophorous, and potassium, which are essential nutrients that plants need to grow and flourish.