January 29, 2024

Nitrogen Fertilizer for Grass: The Complete Guide

What is nitrogen fertilizer for grass? What does nitrogen do for your grass? How much nitrogen fertilizer do you need for your grass? These are all important questions that we want to help you answer.  

Fertilizer is tricky because there are so many different types. There are so many kinds of fertilizer that it can be daunting to make a choice. In this guide, we hope to answer some of your burning questions about nitrogen fertilizer and show which fertilizer you need. Let’s answer some of your questions:  

What is nitrogen fertilizer for grass? 

Nitrogen fertilizer for grass is like a power-up. It's a specially formulated fertilizer that contains a high concentration of nitrogen, which is an essential nutrient for the growth and development of your grass. Think of it as a booster shot that gives your grass the nutrients it needs to thrive. Nitrogen fertilizer for your grass comes in various forms like granules, liquid, or slow-release pellets, making it easy to apply to your lawn. By providing that extra dose of nitrogen, this fertilizer helps promote healthy leaf growth, vibrant green color, and overall lushness in your grass. So, if you want your lawn to be the envy of the neighborhood, nitrogen fertilizer is your go-to. 

Nitrogen fertilizer for grass works wonders in several ways: 

  • Promotes Growth: The high concentration of nitrogen in the fertilizer stimulates the growth of shoots, which leads to a denser and thicker grass cover. This helps your lawn fill in any bare spots and creates a lush, full appearance. 
  • Enhances Leaf Development: Nitrogen is a key component in chlorophyll production, the pigment that gives plants their green color and plays a vital role in photosynthesis. By providing an ample supply of nitrogen, the fertilizer supports the development of healthy, vibrant leaves, resulting in a visually appealing lawn. 
  • Increases Root Development: Nitrogen is not only responsible for above-ground growth but also plays a crucial role in root development. As the shoots grow, they encourage root growth, helping the grass establish a strong and deep root system. This improves overall drought resistance and nutrient uptake. 
  • Improves Nutrient Availability: Nitrogen fertilizer helps optimize soil nutrient levels. It assists in releasing other nutrients, such as phosphorus and potassium, from the soil, making them more accessible to the grass. This ensures that your lawn receives a well-rounded supply of essential nutrients for optimal health. 

However, it's important to apply nitrogen fertilizer in the appropriate amounts and at the right time. Overapplication can lead to excessive growth, increased vulnerability to diseases, and environmental issues like runoff. When it comes to determining the amount of nitrogen fertilizer needed for your grass, it depends on various factors such as the type of grass, soil conditions, and desired results. Here are some general guidelines based on my search: 

  • Rutgers University recommends applying one pound of nitrogen or mixed fertilizer per 1,000 square feet of lawn, assuming your fertilizer contains 20% nitrogen. This calculation can help you determine the appropriate amount for your specific lawn. (Source: Rutgers NJAES
  • The Lawn Care Nut suggests staying between the range of ½ to ¾ pounds of nitrogen per application. However, they mention that it's acceptable to exceed this range slightly. (Source: The Lawn Care Nut

It's important to note that these recommendations provide a general starting point, but it's always a good idea to consider local conditions, follow product instructions, and consult with local experts for more precise recommendations based on your specific lawn. 

Now let’s move on to N-P-K ratios. 

What are N-P-K ratios? 

N-P-K ratios refer to the amount of nitrogen (N), phosphorus (P) and potassium (K), found in fertilizers. These ratios are typically represented in a three-number format, like N-P-K. 

For example: 

  • A fertilizer with a ratio of 10-5-5 means it contains 10% nitrogen, 5% phosphorus, and 5% potassium. 
  • A ratio of 20-10-10 indicates a fertilizer with 20% nitrogen, 10% phosphorus, and 10% potassium. 

The numbers in the ratio represent the percentages of nitrogen, phosphorus, and potassium, respectively. 

Different plants have varying nutrient requirements, so selecting the appropriate nitrogen ratio depends on the specific needs of the plant or crop. For example, leafy green vegetables generally benefit from higher nitrogen ratios to promote lush foliage growth, while flowering plants may benefit from a balanced ratio to support both flower and root development. 

It's essential to consider the specific requirements of your plants, soil conditions, and any soil tests conducted to determine the most suitable nitrogen ratio for optimal growth and health. 

Isolated patch of turfgrass. Nitrogen fertilizer for grass really helps this grass grow.

What are the different kinds of N-P-K fertilizers? 

There are various types of N-P-K fertilizers available on the market, each with different compositions and uses. Here are some common types: 

  • Complete Fertilizers: These fertilizers contain all three major nutrients – nitrogen (N), phosphorus (P), and potassium (K) – in varying ratios. They are often labeled with an N-P-K ratio, such as 10-10-10 or 20-10-10, indicating the percentage of each nutrient in the fertilizer. 
  • Nitrogen Fertilizers: These fertilizers are high in nitrogen content and are used to promote vegetative growth. They typically have a high first number in the N-P-K ratio. Examples include urea (46-0-0), ammonium nitrate (34-0-0), and calcium nitrate (15.5-0-0). 
  • Phosphorus Fertilizers: These fertilizers are rich in phosphorus and are beneficial for promoting root development and flowering. They usually have the second highest number in the N-P-K ratio. Examples include diammonium phosphate (18-46-0) and triple superphosphate (0-46-0). 
  • Potassium Fertilizers: These fertilizers are high in potassium and are important for overall plant health, stress resistance, and fruiting. They tend to have a higher third number in the N-P-K ratio. Examples include potassium chloride (0-0-60) and potassium sulfate (0-0-50). 
  • Balanced Fertilizers: These fertilizers have equal or similar ratios of N-P-K, such as 10-10-10 or 14-14-14. They provide a balanced supply of essential nutrients for general plant growth. 
  • Slow-Release Fertilizers: These fertilizers release nutrients gradually over an extended period, providing a steady supply to plants. They can be formulated with different N-P-K ratios and are often labeled as controlled-release or timed-release fertilizers. 

It's important to choose a fertilizer based on the specific needs of your plants, soil conditions, and the recommendations of soil tests or local gardening experts. 

What N-P-K ratio does your grass need? Well, that depends. For a full list of turfgrass and fertilizers needed by each variety, check out this turfgrass guide.