Fertilization is one of the most important components of a healthy lawn. Grass, especially high-maintenance turf grasses such as modified Kentucky bluegrass, are heavy nutrient fertilizers. When grass uses more nutrients than is replaced in the lawn, the plant weakens, making it more susceptible to disease and damage. Regular fertilization replaces the nutrients in the soil and keeps your grass healthy.
Fertilizer is identified by the three numbers printed on a bag's label. Numbers show the three major nutrient components of the fertilizer by weight: nitrogen (N), phosphate (PO) and potash or potassium (K), respectively, according to the University of Wisconsin Cooperative Extension Service. A fertilizer bag showing 25-10-10 is 25 percent N, 10 percent PO and 10 percent K. Fertilizers are sold in fast- and slow-release forms. Slow release is better for sandy soils that leech water and nutrients, while quick release is best for clay soils that retain nutrients long after application.
Application of fertilizer is determined by the weight of nitrogen present in the fertilizer says the Clemson University Extension. Nitrogen weight in the fertilizer is determined by dividing the percent on the label into 100 or by multiplying the weight of the bag by the percentage of nitrogen. Nitrogen is applied at a rate of pounds to 1,000 square feet of lawn. Grass type determines how many pounds of fertilizer per 1,000 feet is required.
Syntheic vs. Organic
Synthetic fertilizers are made of chemicals that are either sprayed or dropped on the lawn in granular form. Chemical fertilizers, according to Ohio State University, generally release nutrients quicker than organic fertilizer. Organic fertilizer is made of animal manure, or previously living plant or animal sources, such as corn husks, bone or fish meal.
Fertilizer is spread using either a spraying wand or a spreader. Application is best done when it's not windy or rainy because that will create fertilization drift or leeching. Ohio State University recommends fertilizer applications in the late summer, then again at the end of November before the grass goes into winter dormancy period. These application times promote healthy growth and prevents disease over the winter months.
Soil testing is the best way to determine the fertilization needs for the lawn. PH strips are available at garden centers or soil samples can be sent to a university cooperative extension service for a small fee. University soil labs will give recommendations of how best to fertilize the lawn to reach the ideal pH level of between 6.0 and 7.0 acidity. This prevents mistakes in fertilizer application.