Lawn fertilizer, also known as "lawn food," provides essential nutrients to grass, such as nitrogen, phosphorus, and potassium, which help it grow stronger and healthier. Applying fertilizer can also promote grass greening and enhance its overall appearance.
How your lawn reacts to fertilizer depends on many factors, including the air and soil temperature, soil moisture, what kind and how many microbes you have in your soil, and especially the type of fertilizer you use.
It is vital to use the correct amount of fertilizer and to apply it at the right time of year based on the specific needs of the lawn.
Nitrogen in Lawn Fertilizer
Nitrogen is the most important nutrient in fertilizer and plays a vital role in the growth and development of grass. The nitrogen in fertilizer promotes lush, green growth and strong, healthy roots.
In traditional fertilizers, nitrogen comes from ammonium, nitrate, and urea compounds. These dissolve readily in water, so once wet; they quickly break down into ammonium nitrate, the form of nitrogen that grass uses. This is commonly referred to as "quick-release" nitrogen. The advantage of "quick-release" nitrogen is that it promotes faster grass greening due to the instant availability of nitrogen.
The downside of quick-release nitrogen is that it can burn a lawn when spilled or overapplied, generally breaks down within eight weeks, and is prone to losing nitrogen into the air and through leaching when rain carries the dissolved runoff into streams.
Slow-Release Nitrogen Fertilizer
Fertilizer manufacturers have developed slow-release and controlled-release fertilizers to compensate for the possible adverse effects of traditional fertilizers. Slow-release fertilizers are designed to:
- Minimize the risk of causing damage to the lawn by over-fertilization or burn.
- Prolong the period during which the fertilizer is active and providing nutrients, from a few weeks to several months.
- Decrease the amount of nitrogen that leaches out and potentially contaminates water sources.
Coating nitrogen compounds with sulfur or a polymer is a method to release the nitrogen slowly over time. The coating is gradually worn away by soil microbes and water, which makes the nitrogen release slower and more controlled than with quick-release sources that don't have a coating.
Weather and soil conditions can affect nitrogen release rate in coated fertilizers. Warmer temperatures and damp soil can speed up the release. At the same time, cool and dry conditions can slow it down, especially for sulfur-coated products, which rely more on soil moisture and microbial activity than polymer-coated products.
The nitrogen release rate also depends on the quality of the coating and the degree of cracking or breaking that may occur after manufacturing.
Even though coated fertilizers rarely burn, they can sometimes leave spots on lawns when the breakdown factors vary enough.
We suggested applying granular fertilizers to your lawn before it rains or watering them right after they were put down to ensure a proper release rate.
Methylene Urea Nitrogen
Methylene urea is a slow-release nitrogen that is released gradually over time rather than all at once. It combines urea with an organic aldehyde compound (most often formaldehyde). Soil microbes slowly break down methylene urea at a predictable rate influenced by temperature and soil moisture.
Methylene urea's breakdown rate varies depending on a lawn's nitrogen needs. In other words, the release rate naturally slows in cooler weather when grass-growth needs are less and speeds up when the weather warms, and grass-growth rates increase. An advantage of methylene urea nitrogen is that it retains its slow-release rate even if the granules are cracked, chipped, or crushed.
Approximately three-fifths of the nitrogen in GreenView's Fairway Formula Lawn Fertilizers come from methylene urea, while the remaining portion comes from sources of quick-release urea. The result is a product that quickly greens lawns (from the quick-release urea) but is also less likely to burn and is effective for 12 weeks per application (from the slow-release methylene urea). This means lawn owners only have to apply fertilizer twice a year instead of four times.
If you have had lawn weed problems in past years, consider opting for Fairway Formula Spring Fertilizer Weed & Feed and Crabgrass Preventer, which prevents and controls over 200+ broadleaf weeds, including dandelion, crabgrass, plantain, and clover, while fertilizing for up to 12 weeks.
Apply Fairway Formula 30-0-12 Fall Fertilizer in early fall to repair lawn damage caused by heat, drought, pests, or foot traffic. The fall version contains slightly more potassium and less sulfur than the spring version.
Depending on the size of your lawn, you may need to apply the fertilizer in multiple applications throughout the season to ensure that each area receives the proper amount of nutrients. Additionally, you should water your lawn regularly and mow it at the recommended height to help keep your lawn looking its best.
Organic fertilizers are made from by-products of plant and animal processing. They offer an alternative approach to controlling a lawn's nitrogen use.
These fertilizers break down gradually and naturally over time. However, their nutrient rates are relatively low – typically a third or less than the nutrient rates of the above coated and methylene-urea products.
For those leaning organic, GreenView offers Turf Nurture Natural Base Lawn Fertilizer which is a blend of natural organics (feather meal, soy protein, and meat and bone meal) with methylene urea for a product that boosts nutrient levels while avoiding burn, limiting runoff, and extending the release time of the nitrogen.
Turf Nurture has a nutrition breakdown of 15-0-7 and can be applied whenever grass is actively growing.