Lawns and gardens need to be fertilized because most soils do not provide the essential nutrients required for optimum growth. Even if you are lucky enough to start with great soil, as your plants grow, they absorb nutrients and leave the soil less fertile.
By fertilizing your lawn and garden, you replenish lost nutrients and ensure that this year's plants have the food they need to flourish.
There are six primary nutrients that plants require. Plants get the first three—carbon, hydrogen and oxygen—from air and water. The other three are nitrogen, phosphorus and potassium.
The Essential Nutrients
|Governs overall plant health and growth above-ground. Accelerates growth and deepens the green color in grasses. Nitrogen should be applied with a balanced hand – too much makes plants grow quicker than their roots can support.
|The essential element for strong root development. Plants with proper amounts of Phosphorus are also more resistant to disease and have improved seed production, fruit growth, blooming and flowering.
|Potassium plays more of a behind-the-scenes role than Nitrogen or Phosphorous, but still is necessary for optimizing plant health. Potassium improves water retention and disease resistance while protecting plants from cold weather.
Using this chart, you can determine the percentages of these nutrients in a fertilizer. A 5-2-0 fertilizer like Milorganite is 5% Nitrogen, 2% Phosphorus and 0% Potassium.
Fertilizers come from many sources. Synthetic fertilizers are manufactured from minerals, gasses from the air, and waste materials. Organic fertilizers obtain their nutrients from natural organic sources such as microbes, organic wastes, and other similar materials. Learn more about the differences between organic and synthetic fertilizers.