Like all plants, turf grass needs nutrients to thrive. The most important nutrient for grass is nitrogen, followed by potassium and then phosphorous. Additionally, fertilizer should provide minor nutrients that the soil is deficient in.
Homeowners should have their soil tested every 3 to 5 years. A soil test can tell the nutrient balance of the soil. Homeowners can choose a fertilizer that supplies nutrients that the soil is deficient in.
Nitrogen is the most important element for lawns. Nitrogen in fertilizer promotes vigorous growth and green color. The amount of nitrogen a lawn needs varies among turf grass types.
Phosphorous is important to lawns in smaller amounts to stimulate root growth. Potassium is more important than phosphorous because it helps turf grasses to use nitrogen efficiently.
Fertilizer is labeled with N-P-K numbers that indicate the ratio of nitrogen, phosphorous and potassium in the fertilizer. The best fertilizers for lawns have high N number, low P number and a moderately-high K number such as 22-3-14, 29-2-5 or 20-4-8.