The nutrients provided by organic fertilizers are generally more readily metabolized by plants and are frequently preferred by many gardeners. Organic fertilizers also tend to break down slowly in the soil, so they are usually quite long lasting. This means that using organic fertilizers will generally cost slightly more than using chemical types for the same amount of plant food. Chemical Fertilizers Chemical fertilizers, contrary to popular belief, are generally natural in origin, often occurring as natural mineral deposits in many parts of the world. These deposits are then mined and the valuable chemicals found in the rock is ground and purified for sale.
Chemical fertilizers are usually very uniform and consistent in their plant food content.
Some of the chemicals used in such fertilizers are manufactured synthetically and formulated to achieve some special purpose, such as liquid spray application fertilizers. Examples of chemical fertilizers include Sulfate of Ammonia, Superphosphate and Sulfate of Potash. In general, chemical fertilizers are the cheapest way of providing plants with the essential nutrients they require and, since they are very consistent, accurate dosing may be achieved. They are also usually more easily dissolved in water than are organic fertilizer, so they act more quickly, but don't last as long, and are generally more easily leached out soils. Chemical fertilizers, if misused, can contribute significantly to surface water pollution as rainfall or irrigation dissolves the chemicals and washes them down into storm drains and sewers.