A Guide to Greener Grass - Selecting the Proper Fertilizer for Your Lawn

Amir Tajer

Posted on April 19 2018

Having a yard with luscious, green grass is ideal, but is not always the easiest to achieve. Many turn to fertilizer to help with lawn care, but with all the options available on the market, how do you know which one to choose?

Read on to learn how to diagnose your lawn and what factors you should consider before deciding what fertilizer is best for your lawn's needs.

Symptoms of a Sick Lawn

Healthy grass is thick, uniformly green and weed-free. When you run your hand over the top of healthy grass, it will feel like plush carpet – bouncy, springy and resilient.

Alternately, sick lawns will suffer from one or more of the following:

Minimal or no thatch  Composed of roots, grass stems, clippings and other debris, thatch plays a vital role in regulating temperature, insulating soil and evenly distributing moisture in lawns. Thatch accumulates on top and just below soil. In healthy lawns, thatch is usually self-decomposing so you don't have to worry about it growing excessively.

Soil pH imbalance – Brown, yellow and dead spots could indicate problems with soil pH. A pH level between 6.6 and 7.3 is considered neutral. Numbers above 7.3 indicate a more alkaline soil while numbers below 6.5 indicate a more acidic soil. Plant and grass growth may be severely restricted if the soil is too alkaline. A good pH for many grass types is between 6.5 and 7.0 but some grass types tolerate various ranges of soil pH levels.

Fungal growth – Mysterious circles of pale green or white grass emerge in otherwise healthy grass if fungal threads have contaminated the soil. Initially, this "grass ring" may appear greener and thicker than the grass surrounding the ring. This happens because decaying organic matter provides more nutrients and moisture to the ground before starving grass roots.

Weed invasion – Weed overgrowth in lawns is typically caused by improper mowing, irrigation or fertilization practices. Identifying what kinds of weeds are overtaking your lawn is helpful to implementing a successful weed control plan that includes a lawn fertilizer and correct lawn maintenance.

What Should You Consider Before Choosing a Lawn Fertilizer?

Grass Type

All grass types require potassium, phosphorous, nitrogen and water to thrive. Common types of grass include Kentucky blue grass, perennial rye grass, tall or red fescue, Bermuda grass and zoysia grass. While all grass needs the proper amount of nutrients provided by lawn fertilizers, some grasses require less watering and lawn maintenance than others.

Nutrient Content of Your Lawn

Before choosing a fertilizer, it’s best to determine soil pH to get a good idea of what nutrients your lawn needs. This correctly addresses nutrient deficiencies and avoids feeding your grass excess nutrients that can be harmful to plant health.

Strongly alkaline soils should be fed a fertilizer that eliminates iron chlorisis – a condition preventing grass from taking up iron. Zoysia and Bluegrass are susceptible to iron deficiency. Soils presenting neutral or near neutral pH levels facilitate absorption of nutrients necessary for healthy grass.

Method and Frequency of Applying Fertilizer

When it comes to fertilizing your lawn, the application process largely determines the effectiveness of the fertilizer. You want to fertilize cool-season grass types (Kentucky bluegrass, tall fescue and perennial rye) in spring and early fall and warm-season grass types (Bermuda, Buffalo and Zoysia) in later spring and late summer.

 Broadcast or drop spreaders are used to feed lawns with dry fertilizer, while water soluble or liquid fertilizers require hose-end applicators to spray fertilizers over your lawn.

N-P-K Ratios

A fertilizer's nutrient quality is designated by its N (nitrogen), P (phosphorous) and K (potassium) ratio. For example, fertilizers with an N-P-K ratio of 15-15-15 indicates it contains equal amounts of these three nutrients. Fertilizers with N-P-K ratings of 21-8-14 provide high concentrations of nitrogen (21 percent), four times the amount of phosphorous (eight percent) and about half the amount of potassium (14 percent) included in the fertilizer.

Choosing the right N-P-K ratio is vital to growing healthy grass. Learn more about N-P-K ratios of fertilizers here.

What is the Difference Between Organic and Chemical Fertilizers?

Although chemical and organic fertilizers have their pros and cons, when selecting one over the other, it really comes down to personal preference.

Processed (chemical) fertilizers are manufactured from petroleum, animal and/or rock-derived products. During refinement of chemical fertilizers, nutrients are super-concentrated to facilitate absorption by grass and other plants.

Composed of plant, animal, mined minerals and other natural materials, organic fertilizers require minimal to no refinement. Examples of ingredients found in organic fertilizers include manure, rock phosphate, blood meal, fish by-products and cottonseed meal.

Organic fertilizers release nutrients slower than chemical fertilizers because soil-based biochemical processes take longer to start releasing nutrients.

Should I use Urea or Ammonium Sulfate?

Two types of lawn fertilizer you may have seen on the market are Urea and Ammonium Sulfate. Both are nitrogen rich fertilizers and quick release, making them perfect for rapid growth in turf and natural lawns, alike. But they also have their advantages and disadvantages depending on what you are trying to achieve.

Urea

Processed from ammonia, our water soluble, heavy metal free Urea fertilizer is rich in nitrogen and has an N-P-K of 46-0-0. Soil microbes convert urea into nitrogen soon after the fertilizer is applied. For maximum effectiveness, mix soil with urea fertilizer to prevent loss of beneficial gases created when urea changes to ammonium bicarbonate before it converts to nitrogen.

Advantages of urea fertilizer include its affordability, easy storage and safe combination with other fertilizers. Grass types that prefer acidic soil thrive when fed urea fertilizer.

Ammonium Sulfate

High alkaline soils on the other hand, benefit the most from ammonium sulfate fertilizers because it provides sulfur to lower soil pH.

Our water soluble, Ammonium Sulfate fertilizer contains 24 percent sulfur and 21 percent nitrogen. The kind of nitrogen contained in ammonium sulfate is immediately available for root uptake. It’s also easy to store and will not melt in high humidity like ammonia nitrate does.

However, lawn owners should be aware that ammonium sulfate may elevate acidity levels of soil which can negatively impact most types of grass.

You can apply ammonium sulfate either diluted in water or as top dressings for lawns. Regular lawn maintenance should include ammonium sulfate fertilizer to reduce soil pH in severely alkaline lawns and to stimulate grass growth.

So which fertilizer will you choose? Whether you choose to purchase Ammonium Sulfate or Urea, you will surely experience a healthier lawn in no time!