How Often Can I Put Nitrogen on My Lawn?

Nitrogen

• Plants need nitrogen for protein production and photosynthesis. Nitrogen is a key component in chlorophyll, the pigment that makes plants green; therefore nitrogen promotes a lush, green color in your lawn. Nitrogen stimulates dense growth and helps turf grasses stay healthy to fight off diseases.

Why Fertilize?

• Although the air is made up of 78 percent nitrogen, most plants cannot use atmospheric nitrogen. The nitrogen cycle, which uses precipitation to move the nitrogen from the air to the soil where microorganisms turn it into plant-usable nitrogen, often takes too long to replenish the nitrogen in the lawn before the grass shows evidence of a deficiency. Fertilizers are applied to counteract this deficiency.

How Often?

• The types of lawn grass and your area's climatic conditions determine when your lawn needs an application of nitrogen fertilizer. For example, Texas A & M Extension Turf Grass Specialist R. L. Duble recommends two applications of a general fertilizer per year, plus two applications of a nitrogen fertilizer during the summer months for southern areas of Texas. John Street, a horticulturist from the Ohio State University Extension, recommends fall and late fall applications of fertilizers over spring and summer applications. Check with your county cooperative extension office for the best practices in your area.

Precautions

• Although the proper use of nitrogen for fertilizing your lawn helps create a healthy lawn, misuse is costly. Nitrogen fertilizers need water and time to change the nitrogen into a form that plants can use. Unused nitrogen leaches into the soil and away from plant roots or runs off with rainwater or irrigation water, potentially contaminating waterways. Over-fertilization also promotes disease and rapid growth, and rapid growth means more mowing for you. Under-fertilization leads to yellowed lawns that invite pests and disease. Always follow the manufacturers recommendations when applying nitrogen fertilizers.