A lush, rich green lawn is what we all strive for when growing grass. Nitrogen fertilizers and ample water each play a key role in maintaining a green lawn, according to Purdue University. Mowing height also contributes to the green appearance of the lawn, with slightly longer blade lengths resulting in a greener appearance. Apply lawn fertilizer when planting or sodding a lawn and several times each year thereafter to maintain vigorous green growth.
Select a high-nitrogen fertilizer product designed for lawn grass with both slow-release and quick-release forms of nitrogen. Look for a product with a guaranteed analysis of 24-4-8 or a similar ratio of nitrogen to phosphorous and potassium, respectively.
Fertilize your lawn grass two to three times per year. Start with a light feeding in spring, then use a very light application to no fertilizer in summer, and fertilize most heavily in the fall. Heavy fall feeding boosts the root strength and results in vigorous green growth all year and does not contribute to weak growth or insect populations. Cool climates with short growing seasons can skip the summer application entirely.
Apply the amount of fertilizer recommended on the product label for your specific square footage of lawn area, type of soil and type of grass. Always err on the side of less, not more fertilizer if in doubt. Excess fertilizer can burn lawns, run off into nearby bodies of water or cause weak, disease-prone growth.
Apply fertilizer evenly over the lawn by hand-casting or with a spreader tool working from one end of the lawn area to the other, overlapping rows slightly so all of the area is covered.
Immediately follow each fertilizer application with a deep watering to wash the fertilizer nutrients down to the surface of the soil and into the root zone. Drench the soil down to at least 3 inches below the thatch and repeat watering once or twice a week with 1 inch of water per week. Warm, dry climates or certain kinds of grass will require more water. Rainy climates may require less.