Function

• Nitrogen, called a macronutrient, is crucial for photosynthesis--the process by which plants make food for themselves. All plants must have nitrogen to survive. The chloroplasts in the plants carry out photosynthesis. If they do not receive enough nitrogen, they will not work correctly, and the plants will turn yellow. Lawn grass needs nutrients to maintain health and color, as well. The essential nutrients are not always present in the soil or they may not be in proper ratios for optimum plant growth. Fertilizers can provide nitrogen, potassium and phosphorous needed to grow healthy grass lawns.
  
  

Types

• Two types of lawn fertilizer exist, and both types contain nitrogen: organic and inorganic. Organic fertilizer, composed of organic materials such as decaying animals and plants, doesn't break down as quickly for plant consumption as inorganic. But organic fertilizer is kinder to the environment because it doesn't harm groundwater or produce the down-river problems that inorganic fertilizers can.
  
  

Significance

• Typically, the label on inorganic fertilizers can help you select the product and nitrogen level appropriate for your grass type. However, manure and compost are not labeled to indicate the ratio of nutrients.
  
  

Features

• The nitrogen in fertilizer can be controlled-release or fast-release. Slow-release formulas generally produce a more uniform grass color. These formulas are less likely to dissipate through the air or soil and less likely to burn your grass. Fast-release nitrogen is usually cheaper, provides needed nitrogen even if the soil is cold and responds quickly to return your lawn to a green color.
  
  

Misconceptions

• Your lawn will not always need equal amounts of nitrogen, phosphorous and potassium. For example, when lawn grass is growing more actively during the summer, you may need more nitrogen. If you are just establishing your lawn, use a fertilizer with a greater percentage of phosphorous than nitrogen or potassium.