The main disadvantages of using artificial, or inorganic, fertilizers, according to the Clemson University Extension, is that they risk polluting the groundwater, and some inorganic fertilizers can harm plants if they are allowed to remain on the foliage. Also, they do not add as many nutrients to the soil as organic fertilizers and need to be applied more often than natural fertilizers, according to the Oregon State University Extension.
The nutrients in artificial fertilizers do not stay in the soil for very long. For this reason, gardeners must apply inorganic fertilizers to their soil more often than organic fertilizers. Inorganic fertilizers that release their nutrients into the soil more slowly, and thus require fewer applications, are available from some manufacturers.
Artificial fertilizers go through a manufacturing process, while organic fertilizers, such as manure, typically do not undergo this type of treatment. The treatment process creates fertilizers that are very high in the three primary nutrients plants need, which are nitrogen, phosphorus and potassium. Because inorganic fertilizers have such high concentrations of these minerals, they work more rapidly than fertilizers such as manure and compost. This is why artificial fertilizers are so popular with home gardeners and farmers despite their potential disadvantages.