Fertilizer acts as vitamins for your lawn.  Using too much is harmful.  Using too little—when needed—can result in poor health and susceptibility to diseases.  A healthy, properly-maintained lawn is pleasing to look at, increases the value of a home and provides many environmental benefits relating to air and water quality, according to scientific research gathered by The Lawn Institute.

Maintaining a healthy, environmentally beneficial lawn requires proper maintenance techniques, from mowing and watering, to fertilizing and occasionally pesticides and herbicides.

When Should You Fertilize Your Lawn?
The most effective time to apply fertilizer to your lawn depends on where you are geographically located and the type of grass you have.  The best time to fertilize warm-season grasses is mid-summer; for cool-season grasses, it is late spring or early fall. 

What Type and How Much Fertilizer Should You Use?
Lawns within each geographic or climatic region of the country are different.  Ideally, contact your state’s agricultural extension agency to find out the procedures for conducting a soil sampling and analysis to determine your lawn’s fertility needs.  At the very least, ask your local lawn & garden retailer which fertilizer is best and when it should be applied.

Proper application
To assure uniform coverage use a broadcast spreader adjusting the spreader application dial to distribute one-half of the fertilizer bag’s recommended setting.  This allows for two applications of the recommended coverage which assures even and thorough coverage.  Make the first application in an up-and-down pattern, covering the entire lawn.  Begin the second application immediately, in a left-to-right pattern to cover the entire lawn.

What’s in a Bag of Fertilizer?
A typical lawn fertilizer bag’s label has three numbers, such as 5-10-5, indicating the contents.  Those numbers represent the ratios, by weight, of three major macronutrients: nitrogen (N), phosphorus (P) and potassium (K), all of which are essential to healthy plant life.  For example, a 50-lb. bag of fertilizer labeled 5-10-5 has 5% N (2.5 lbs.), 10% P (5 lbs.), and 5% K (2.5 lbs.).  The bag’s remaining 80% (40 lbs.) by weight is a carrier for the fertilizer, making it easier to apply to your lawn.

The importance of these macronutrients is: N gives plants the ability to grow rapidly and produce large amounts of succulent, green leaves; P plays an important role in seedling development, cell building and root growth; and K helps the overall cell structure of a plant by making it more resistant to disease and physical damage due to heavy foot traffic.  When properly applied, these macronutrients encourage a healthy lawn which significantly contributes to a healthier environment than a lawn that receives no nutrients.

Misinformation about Phosphorus
Lack of scientific knowledge has led to a major misconception about phosphorus.

Myth: The use of phosphorus on your lawn is bad for the environment.

Scientific Fact: Scientists have determined that phosphorus run-off from non-fertilized grass is actually as much as 147% higher than run-off from grass that is properly fertilized.