Due in part to the increased awareness of food cultivation in the United States, there has been a new interest in organic products and organic gardening. With this new interest, there has also developed a heated debate as to what type of gardening is better: organic or inorganic. Both types of gardening provide different benefits and disadvantages, so which method is "better" largely depends on your gardening needs.
Organic fertilizers are derived from living organisms or their by-products; some of the more popular examples include fish emulsion, guano, manure, bone meal and blood meal. These organic substances are naturally rich in nitrogen, phosphorus or potassium, all of which are necessary for healthy plants. Because of varied conditions in nature (including annual rainfall or the organisms' diet) the levels of nitrogen, phosphorus and potassium can fluctuate greatly. Although naturally occurring, organic materials cannot be used by a plant directly. Organic materials must first be broken down by microorganisms in the soil to be available for use by the plant, which can be a lengthy process. If the plant is in need of a specific nutrient immediately, an organic fertilizer will not be effective because of the time it takes to breakdown into a usable form. This slow breakdown of organic nutrients can also be beneficial because you are less likely to suffer from over-fertilization. Over time, organic nutrients help build soil structure and and the soil's ability to hold nutrients and water.
Inorganic or synthetic fertilizers refine nutrients from inorganic sources, such as rocks, petroleum or from organic substances. Although some manufactured fertilizers come from organic sources, they differ primarily because the synthetic nutrients are stripped to a more basic state. In isolating the synthetic nutrient, manufacturers eliminate the need for nutrient processing in the soil itself and also works to make the content of the nutrient more reliable. Plants can readily use synthetic nutrients because they have already been broken down to a usable state. This benefit can be particularly useful if your plant is experiencing some sort of nutrient emergency because the necessary nutrients will be absorbed quickly and easily by the plant. However, because synthetic nutrients are so easily absorbed by plants, there also lies a greater threat of over-fertilization. Plants can easily be burned through too much nutrients. Another drawback of synthetic nutrients is that they are very susceptible to leaching, or washing away. Manufactured nutrients do little to build the soil and may actually cause long term damage to soil through pH changes or salt buildup. However, these problems are less of an issue with indoor gardens that are grown hydroponically.
The choice to grow organically or inorganically ultimately lies with the grower. There are benefits and drawbacks to both types of gardening, so make sure you know what will benefit you and your garden most before choosing.