Turf grass is often a hungry ground cover, requiring lots of nutrients to survive and thrive. Most soils do not have enough nitrogen, says the University of Minnesota Extension, to maintain a healthy turf. Too much fertilization, however, will cause foliage burning, as well as accelerated top growth and reduced root depth.
Before applying fertilizer to a turf grass lawn, perform a soil test, says the University of Arkansas. A soil test determines the pH, or soil acidity, of the lawn and the potassium and phosphorous levels. Collect soil samples from several locations in the lawn to a depth of 4 to 6 inches and test them using a home testing kit or send them to a university extension office. Sample in the late fall or winter, once the soil is depleted, to get the most accurate results.
Calculating the Lawn
To apply fertilizer properly, measure the lawn in square feet. Nitrogen application is made in pounds per square feet. To calculate the area of the lawn, measure the length and width, then multiply the two lengths. Nitrogen is applied by weight per 1,000 square feet of lawn.
The fertilizer label indicates the weight of the macronutrients---nitrogen (N), phosphorous (PO) and potassium (K)---by displaying their percentage in the content of the bag. A 24 lb. bag of fertilizer with a 14-14-14 nutrient content, representing N, PO and K in that order, contains 14 percent of each nutrient by weight, so 24 X .14 = 3.36 pounds of each nutrient in the bag.
Apply fertilizer nutrients to the lawn according to the soil test results. Use a spreading device such as a drop or broadcast fertilizer spreader for the application. According to the University of Minnesota, drop spreaders are more accurate than broadcast spreaders.
Fertilizer pollution is a concern when applying regular applications to the lawn. Avoid drainage areas by the street when fertilizing to prevent fertilizer runoff. Never spray spilled fertilizer with water to remove it. Water minimally after a fertilizer application to prevent the fertilizer from running off and polluting nearby bodies of water.