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Recipe for Fertile Soil

Let's face it, the wonders of soil composition and chemistry are not exactly a turn-on for most casual gardeners. Reading the back of a fertilizer bag is about as far as you get. But you don't have to be an agronomist to know the basics. And learning soil composition 101 is the first step to a healthy garden.

To understand what your plants need from soil, you need to consider 3 basic nutrients: nitrogen, phosphorous and potassium. Each ingredient must be present in the right amount. Too much will hurt the environment, while too little will starve your plants. You'll notice that most fertilizers list the quantity of nitrogen, phosphorous and potassium respectively by their ratios, i.e., 10-20-10 or 10 parts nitrogen to 20 parts phosphorous... you get the drift.

Before you start mixing and matching nutrients you need to know what your soil already has. Go get your soil analyzed. The pick the right fertilizer to add the right amount of each nutrient.

Here's why your soil's chemistry needs to be properly balanced. Starting with nitrogen, you won't get a reading on it from your soil analysis because it doesn't persist in the soil long enough to be measured. But providing the right amount is essential to promoting plant growth. The first sign of nitrogen debt is yellowing leaves or leaves turning a lighter shade of green. Without it, plants don't develop foliage or leaves like they should or synthesize sunlight for energy. Too much of it, however, burns the roots and stunts flowers. Although you won't see it, the excess nitrogen will leach into groundwater supplies or run off into water bodies, creating environmental and human health problems.

The right dose of phosphate or phosphorous also adds a lot to your recipe because it helps plant growth, especially in producing seeds, fruits and flowers. Your plants also need it to resist diseases. Anemic flowers and darker or reddish-colored leaves will show up on a plant in phosphorous-poor soil. An overdose of phosphorous, on the other hand, doesn't serve your plants or the environment. Potassium also contributes to disease-resistance, as well as strong stems and robust growth. It also increases water uptake.

Finally, pay attention to the pH measurement of your soil's analysis. Keep your soil around 6.0 to 6.5, not too acidic and not too alkaline. However, remember that certain plant species may prefer a higher pH. Lime can be applied to highly acidic soils, while sulfur can be added to alkaline soils to lower the pH.

Sources used to create this article include Michele Shoup and the New Orleans Times-Picayune.

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