Nitrogen is the primary element responsible for the deep green color in grass, acting as a foundational ingredient for a healthy lawn. This element is categorized as an essential macronutrient because plants require it in large quantities to support vigorous growth and survival. Without sufficient amounts of nitrogen, the grass cannot properly execute the biological processes that give it its desirable appearance. The presence of nitrogen directly influences the vibrancy and density of the turf, which is why it is the most prominent nutrient in most lawn fertilizers.
Nitrogen’s Role in Chlorophyll Production
The rich green color of grass is a direct result of a pigment called chlorophyll, and nitrogen forms a structural component of every chlorophyll molecule. Chlorophyll is the substance that captures sunlight and initiates photosynthesis, the process plants use to convert light energy into chemical energy for food production. If the grass lacks nitrogen, it cannot produce enough chlorophyll, which limits its ability to absorb light and manufacture the necessary energy for growth.
This function makes nitrogen a fundamental building block for the grass plant’s cells, proteins, and enzymes, driving rapid leaf and blade development. Adequate nitrogen levels ensure the grass remains dense and robust, promoting a thick turf that can better resist environmental stresses like foot traffic and drought.
Recognizing Nitrogen Deficiency
A lawn suffering from insufficient nitrogen will exhibit visual symptoms, which turf professionals refer to as chlorosis. The grass blades will lose their deep color, appearing pale green or developing a yellow tint. This yellowing typically begins on the older, lower leaves first because nitrogen is a mobile nutrient within the plant.
As the plant’s supply runs low, it relocates nitrogen from older leaves to support newer growth at the tips. This nutrient reallocation causes the older blades to display the symptoms of pale coloration first, while the new growth may temporarily remain greener. Along with discoloration, nitrogen deficiency also leads to stunted growth, thin turf density, and a lack of vigor, making the lawn look patchy and sparse.
Safe and Effective Nitrogen Application
Supplying nitrogen to your lawn is primarily achieved through fertilizer application. Fertilizer bags feature an NPK ratio, three numbers representing the percentage by weight of Nitrogen (N), Phosphate (P), and Potash (K). Since nitrogen is the key component for color and growth, a professional lawn fertilizer will often have a higher first number, such as a 20-5-10 ratio.
Nitrogen Forms
Nitrogen is available in two main forms: quick-release and slow-release. Quick-release nitrogen is water-soluble, providing an immediate surge of nutrients that results in a rapid green-up within days, though the effect is short-lived, lasting only a few weeks. Slow-release nitrogen is coated or chemically bound, providing a steady, consistent feed over a much longer period, sometimes up to two months.
Avoiding Fertilizer Burn
To avoid a condition called “fertilizer burn,” which appears as brown, scorched patches on the lawn, you must apply the product accurately. Fertilizer burn occurs because the nitrogen compounds are salts that, when over-applied, draw water out of the grass roots via osmosis, causing dehydration. Always follow the manufacturer’s directions for the correct application rate, and avoid applying fertilizer to a wet lawn or during extreme heat or drought conditions.