Answer: There are positives and negatives to both. Organic fertilizers are made from the remains of once living things, therefore they contain carbon. Inorganic fertilizers are man-made from mineral salts, and contain no carbon. (The definition of organic varies widely, but it usually contains carbon.) Miracle Gro is considered inorganic. At the smallest level that plant roots are taking up nutrients, there is no difference to the plant. However, organic fertilizers (such as fish emulsion, alfalfa meal, blood meal, bone meal) provide long-term benefits to the soil, by giving soil microorganisms and earthworms food. Organic matter also improves the structure and workability of soil over time. Organic fertilizers are less likely to burn plants because they have low concentrations of nutrients (e.g., 5-3-1). Organics are slower working, but remain available to the plants longer. They are usually more expensive.
Inorganic fertilizers are usually less expensive, work faster, and have higher nutrient concentrations (e.g., 15-30-15). However, they leach through the soil faster, and can burn plant roots if improperly applied. Because they contain no organic matter, they don't improve the soil over time. Because they are made of mineral salts, they can cause salt build-up over time. These are a few of the basic differences between the two types.
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