Why not use chemical fertilizers? It’s a reasonable question. After all, nitrogen, phosphorus, and potassium ARE chemicals, so where is the advantage in these bags of heavy, grainy stuff, that need to be measured and mixed and then dug in, when you can just pick up a small plastic bottle of the blue stuff?
There are several organic fertilizer benefits, some purely altruistic, others much more self-interested. First of all, most chemical fertilizers provide only that well-known trio, nitrogen (N), phosphorus (P), and potassium (K). These three, known as the macro-nutrients, are indeed required in greater quantity than any others, but they are only three of the thirteen nutrients plants need. The three chemicals that qualify as secondary nutrients, calcium, sulfur, and magnesium are generally ignored, as are the trace nutrients, boron, chlorine, manganese, iron, zinc, copper, and molybdenum. While these are needed in far smaller quantities than the macro-nutrients, they are still essential. (more…)