What's Actually In A Lawn Fertilizer?

hands holding granular fertilizer for a lawn

Having a lush, green lawn is something that many people strive for. While there are several factors to consider when it comes to creating and maintaining an aesthetically pleasing yard, one of the most important aspects is properly fertilizing your lawn. Fertilizers provide essential nutrients and chemicals that help grass stay healthy and look great. But what exactly is in a fertilizer? In this article, we will explore the most important ingredients in lawn fertilizers so you know exactly what you are feeding your turf!

liquid fertilizer spreader

How Do Lawn Fertilizers Work?

Before we get into the contents of lawn fertilizers, let’s first briefly discuss how fertilizers work in a lawn. Fertilizer acts as a “food” for your grass, providing essential nutrients to help it grow and thrive. The fertilizer you apply to your lawn gets absorbed into the soil and into the roots of your grass. When the lawn is properly fertilized, you will begin to see improvements in color, texture, and growth soon after application. In addition to supplying necessary nutrients, fertilizer also helps improve soil structure by adding organic matter, which also helps control weeds, deter pests, and more.

Granular Fertilizer

Synthetic vs. Organic Fertilizers

When it comes to choosing the right fertilizer for your lawn, there are two main types: synthetic (or chemical) and organic fertilizers. Synthetic or chemical fertilizers provide a quick boost of nutrients that can be readily available to plants within hours of application. This makes them ideal for new growth at the start of the season or lawns that are struggling and need an immediate influx of nutrients. The main ingredients in these varieties are nitrogen, phosphorus, and potassium (the NPK ratio), and many synthetic fertilizers also include micronutrients like zinc, magnesium, iron, and more. These are the types of fertilizers used by professional lawn care companies for their efficacy.

Organic fertilizers, on the other hand, are not manufactured to include certain chemicals and elements. Rather, they rely on natural substances like manure, compost, and other sources of organic matter to nourish the soil. While these types of fertilizers are slower to work than synthetic varieties, they provide a more long-term solution with fewer potential risks. However, these types of fertilizers are better for sustaining a thriving lawn, as they will do little to provide immediate results if your lawn is having issues growing.

Nutrients found in grass clippings all around new grass leaves

Explaining The NPK Ratio

When it comes to finding the right fertilizer for your lawn, one of the most important factors is understanding the NPK ratio. This stands for nitrogen (N), phosphorus (P), and potassium (K). These three elements are essential in helping plants grow and develop properly and can be found in many different kinds of store-bought synthetic fertilizers. The ratio is denoted on the packaging of store-bought synthetic fertilizers as percentages of each element contained in the fertilizer.

For example, seeing “20-20-20” on a fertilizer package means 20% each of nitrogen, phosphorus, and potassium is in the fertilizer for a 1-1-1 ratio. Another example would be “10-5-5” to indicate 10% nitrogen, 5% phosphorus, and 5% potassium for a 2-1-1 ratio. Understanding exactly how much of each macronutrient is present in your fertilizer is crucial to the success of your lawn fertilization efforts, as each nutrient plays a specific role and provides different benefits to your lawn.

Lawn Health

Function Of Nitrogen

Nitrogen is arguably the most important macronutrient found in lawn fertilizer. It helps grass grow faster and thicker, as it encourages photosynthesis by increasing the production of chlorophyll in grass blades and provides a key component to healthy cell development. Chlorophyll’s main function in grass blades is to absorb light from the sun and use that stored energy to convert carbon dioxide and moisture into glucose. 

Chlorophyll is also what gives pigment to grass blades for that much-desired green color. Essentially, nitrogen is necessary for feeding your lawn and helping it grow vibrant and lush. Too much nitrogen, however, can stress your grass and cause it to become discolored, so it is important to pay attention to NPK ratios and follow instructions.

Main Benefits Of Nitrogen:

  • Encourages photosynthesis
  • Taller and thicker grass
  • Quick growth rates
  • Vibrant green coloration
Man Spraying Fertilizer, Wide Image

Function Of Phosphorus

Phosphorus is another important nutrient that helps your grass grow strong and healthy. Its primary function in fertilizer is to ensure that the roots of plants develop properly, which is essential for proper absorption of water and other nutrients within the soil. The early stages of your lawn’s development need phosphorus because it helps protect the weaker, young grass from erosion by establishing sturdier roots. This ingredient also helps nitrogen work more efficiently by encouraging the transfer of energy throughout the plant.

Main Benefits Of Phosphorus:

  • Helps create root systems
  • Protects against erosion
  • Assists energy transfer
  • Supports nitrogen function
winter lawn care

Function Of Potassium

Potassium is the third and final macronutrient that helps grass grow strong and healthy in synthetic fertilizers. This element helps with root development as well, but its main function in lawn fertilizer is to help your grass better tolerate both drought and cold temperatures in cool-season climates like ours. Potassium also assists in disease resistance by helping grass blades strengthen cell walls so they can stand up against environmental pressures like heavy foot traffic, pests, and disease. Potassium is essential for the cool-season grasses used here in Illinois.

Main Benefits Of Potassium:

  • Improves drought tolerance
  • Enhances disease resistance
  • Protects against freezing temperatures
  • Encourages stronger roots
purple granular fertilizer spreader

What's In Weed & Feed?

Weed and feed fertilizer is a combination of a herbicide and fertilizers in an all-in-one product. These products work together to give your lawn full protection against weeds, pests, and disease. In addition to the typical nutrients and chemicals in fertilizers, weed and feed products contain selective, post-emergent herbicides like dicamba, MCPP, or 2,4-D.

These herbicides target broadleaf weeds that have already sprouted up in your lawn, and the product can be applied across your entire lawn to both improve grass health and eradicate these weeds at the same time. Unfortunately, the chemicals in weed and feed do not kill grassy weeds, so non-selective weed killers will have to be applied directly onto weeds like crabgrass and annual bluegrass.

Gloves, fertilizer, and a rake on grass

Elite Lawn Fertilization For Illinois

Ultimately, having a successful and healthy lawn requires the right combination of nutrients, chemicals, and herbicides, among other factors. Knowing how chemicals and different ingredients affect the health of your lawn will go a long way in providing the best lawn care possible. With Elite Lawn Care’s services in Illinois, you can rest assured that all these components are taken into account when we provide our professional fertilization services. Let us help make sure that your lawn gets exactly what it needs so it stays lush and vibrant throughout the year!


Algonquin IL | Lawn Care & Landscaping

Elite Lawn Care offers a full range of lawn care and landscaping services in Algonquin IL, such as mowing, fertilization, weed control, and snow removal, using advanced technology for a vibrant and healthy lawn. Choose Elite for hassle-free maintenance and enjoy a lush, beautiful green space at your home.

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