Organics vs Synthetic
Organic is all the rage. Understandably, organic growing techniques offer many benefits. Looking specifically at fertilizers, it's important to understand the advantages of both organics AND synthetics. Some will call them "chemical" fertilizers. In general, the word chemical carries a bad stigma. But water could be considered a chemical, depending upon definition. So instead, let's call them synthetics.
SYNTHETIC FERTILIZERS - are mostly or entirely man-made in origin. For example: phosphate rock can be mined, then treated with acid to extract water-soluble phosphate salts. This results in a phosphate fertilizer that is more potent than an organic source. This means less volume by weight is required during application. The upfront costs for the fertilizer are often less.
A liquid synthetic fertilizer may provide a quick release of nutrients to plants that are showing signs of malnutrition. Or a granular synthetic may have a special time release coating that supplies a low, constant supply of nutrients over a long period of months. Using synthetics allows for the replenishment of a single macronutrient if soil tests reveal a deficiency.
However, reliance on these fertilizers does little to promote beneficial soil microbes. Sole reliance on synthetics will not build a healthy, living soil profile. A first time gardener may find initial success using synthetics. This is good. With success, comes a continued desire to garden and to learn more. For long-term sustainability many gardeners choose to incorporate organic materials for both structure as well as nutrition.
ORGANIC FERTILIZERS - are derived from natural sources such as minerals, animals or plant by-products. Through the breakdown or decomposition of organics, nutrients are released for plant consumption. Microbes, including beneficial bacteria and fungi are a vital part of this system. This is because the nutrients that are tied up in organic matter are not immediately available for uptake. The decomposition or mineralization process is what reduces organic compounds to their inorganic forms. These ions are then transported in water to the root systems and thus absorbed by the plant.
This process could be likened to the extraction of a refined metal from a metal ore. It takes 2 tons of iron ore to make 1 ton of pig iron. Similarly, organic fertilizers are much like that unrefined ore. They still need to be processed. That's why a larger volume of fertilizer may be needed to reach NPK values that rival synthetics.
But utilizing organic fertilizers can be very beneficial in the long-term. You may find plants are heartier, more resistant to disease and pests. Using organic fertilizers can be a simple process if you are willing to buy a pre-blended, balanced commercial supplement. Or for the adventurous, you could acquire base components and blend them yourself. It can be a fun experience for the more advanced gardener.