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Blue fertilizer in brown bag on green grass

The Complete Guide to Using Lawn Fertilizer

The House Method team researches, reviews, and recommends a number of services, including lawn care providers. Affiliate disclosure.

Healthy lawns start from nutrient-rich soil. Your lawn draws nutrients from the soil up through its roots and uses those nutrients to grow into lush, dense grass. In an ideal world, your lawn’s soil would contain the perfect blend of nutrients your grass needs.

Unfortunately, most of us aren’t that lucky. That’s where fertilizer comes in. Proper lawn fertilizer applications boost your lawn’s ability to grow beautiful, thick grass. Our guide to lawn fertilizer explains how to choose the right fertilizer for your lawn, read the label, and safely apply the fertilizer to your lawn.

Of course, finding the right combination of fertilizers and getting the timing exactly right can be a bit of a hassle. If you decide you don’t have the time to decode fertilizer labels and spend hours behind a fertilizer spreader, we recommend TruGreen as a professional lawn service provider. Learn more about TruGreen’s lawn care packages, including fertilizer application, and get a free quote by giving them a call at 888.535.3193 or filling out their online form.

Benefits of fertilizing your lawn

You might wonder why you need to fertilize your lawn. After all, you’re already watering and mowing it regularly to promote healthy growth. However, an unfertilized lawn must rely solely on the nutrients currently present in your soil. This can vary greatly between lawns even in similar climates or soil types. Soil nutrients may have been lost when your home was built or due to improper lawn care from a previous owner.

Properly fertilizing your lawn not only helps your grass to grow more evenly and efficiently but also helps reduce the appearance of weeds in your grass. Developing a fertilizer application plan for your lawn leads to grass with rich, green coloring and dense coverage across your yard.

Choosing the right lawn fertilizer

When you stop by your local lawn and garden store, you’ll notice an almost endless display of lawn fertilizers for sale. From “weed and feed” to lawn food, fertilizers aren’t lacking in variety. With all of these options, you’re probably wondering how you go about choosing the best lawn fertilizer available.

The reason you’ll see so many varieties of fertilizer reflects the numerous combinations of nutrients individual lawns need to maintain healthy growth.

Composite mineral fertilizers

Most common lawn nutrients

Almost all lawn fertilizers contain one or more of the three major nutrients required for a lawn’s optimum growth. The nutrients Nitrogen (N), Phosphorus (P), and Potassium (K) are most commonly found in grass fertilizer. Not only are they important to plant growth, but they are also usually the most deficient in natural soils. Each nutrient serves a different purpose for promoting ideal plant growth.

Nutrient Name Key Benefits
  • Nitrogen (N)
  • Is responsible for rapid growth
  • Helps synthesize proteins
  • Increases leaf development for dense lawns
  • Phosphorus (P)
  • Helps early root growth
  • Promotes plant maturity
  • Aids in seed development
  • Potassium (K)
  • Helps grass resist drought and disease

Determining what nutrients your lawn needs

There are two main factors that contribute to what nutrients your grass needs. One is the type of grass that is planted in your yard. The other is the existing nutrients available naturally in your lawn’s soil. Both of these factors play an integral role in determining which nutrients your fertilizer should contain.

  • Type of grass—Grasses come in warm-season and cool-season varieties. A warm-season grass that thrives in a Southern state needs different amounts of nutrients than a cool-season grass that grows best in the Pacific Northwest. Knowing what types of grass are planted in your yard can help you choose the right lawn fertilizer.
  • Soil properties—Your soil has one of the largest effects on your fertilizer needs. It’s generally recommended that you perform a soil test to determine which nutrients your soil lacks and the pH level. These simple tests give you a detailed breakdown of your lawn’s soil by collecting a sample and mailing it to a lab.

Translating lawn fertilizer labels

Lawn fertilizer companies don’t always do a fantastic job of making their fertilizer labels understandable. When you buy almost any bag of fertilizer, you’ll see three numbers listed somewhere on the label, such as 20-20-20. These numbers represent the amount of Nitrogen (N), Phosphorus (P), and Potassium (K) in the fertilizer, in that order. Many brands of lawn fertilizer won’t list the nutrient names, so it’s important to remember that the amounts will always be listed in the order of N-P-K.

The numbers themselves represent the percentage of weight of each nutrient. For example, if a bag of fertilizer says 20-5-5 and the bag weighs 50 pounds, there are 10 pounds of Nitrogen in the bag and 2.5 pounds each of Phosphorus and Potassium.

20% (first number in N-P-K sequence) X 50 (pounds of fertilizer in bag) = 10 pounds of Nitrogen

5% (second number) X 50 pounds = 2.5 pounds of Phosphorus

5% (third number) X 50 pounds = 2.5 pounds of Potassium

Lawn fertilizer plans are generally developed on how many pounds of Nitrogen is required per 1000 square foot of lawn per year. If you don’t feel like calculating out the exact amount of nutrients needed by your lawn, there is a simple trick to finding a good grass fertilizer. Looking at the fertilize number sequence, you may notice some have a large amount of one nutrient and lower amounts of others. In the example above, there is a higher percentage of Nitrogen than Phosphorus or Potassium. This is the ratio you typically want for growing grass. Aim to purchase a fertilizer with a higher number for Nitrogen and then a lower number for Phosphorus and Potassium.

garden fertilizer on gardeners hand

Disadvantages of Phosphorus

Although Phosphorus is an important nutrient that all plants need to survive, studies have shown that using Phosphorus in lawn fertilizers may contribute to unnecessary runoff into waterways. This can lead to increased algae blooms that lower the water’s recreational value and may harm wildlife such as fish by depleting oxygen levels in the water.

Phosphorus can still provide a lot of benefits to your lawn, but it is important to use it correctly. Avoiding applying fertilizer around ponds, drainage systems, or other water sources is the number one way to prevent Phosphorus runoff. Additionally, you can test your soil before applying fertilizer to determine the Phosphorus levels. If your lawn has plenty of Phosphorus already, there’s no need to add more, and you can choose a Phosphorus-free fertilizer.

Many companies have stopped adding Phosphorus to their commercial-available fertilizers. Local laws may restrict your use of Phosphorus as a lawn fertilizer. Be sure to check your local city, county, and state laws for Phosphorus restrictions.

Types of Nitrogen fertilizers

Since lawns generally need Nitrogen more than the other major nutrient, lawn fertilizer companies have developed various fertilizer types to effectively get Nitrogen into your soil. Generally, Nitrogen can be applied in controlled-release (also known as slow-release) or quick-release applications. Our chart below looks at the advantages and disadvantages of each type.

Fertilizer type Description Advantages Disadvantages
Controlled-release Granular beads of fertilizer that release nutrients into the soil over a period of 6–8 weeks.
  • Uniform application and growth
  • Less loss of nutrients through the soil or air
  • Less likely to burn the lawn
  • Less frequent applications
  • Less effective on cold soil
  • More expensive
  • Nutrients aren’t readily available, so it will take longer to see a change in your lawn’s color
Quick-release Either a liquid concentrate or water-soluble beads that immediately release nutrients into the soil when watered.
  • Fast response from grass; get a greener lawn faster
  • Less expensive
  • Provides immediate nutrients, even when the soil is cold
  • More likely to burn grass
  • More likely to lose nutrients in air or water and deteriorate soil quality
  • Need more frequent applications

Should I use organic or inorganic fertilizer?

In addition to controlled-release and quick-release lawn fertilizers, there is a distinction between organic fertilizers and inorganic fertilizers.

  • Organic fertilizers—These are natural materials that provide necessary nutrients to your lawn. Though a wide category, most organic (carbon-based) materials from plants and animals contribute to the nutritional makeup of your soil. Examples include manure, compost, bone meal, and alfalfa.
  • Inorganic fertilizers—Also known as chemical fertilizers, inorganic fertilizers are synthetically produced to provide an exact amount of nutrients based on the chemical makeup.

It’s important to look at the pros and cons of each type of fertilizer when choosing the right fertilizer for your lawn. We’ve put together a chart with the advantages and disadvantages of both organic and inorganic fertilizers. Often, the best choice for a lawn is a combination of fast-acting inorganic fertilizers and slow, steady nutrients from an organic fertilizer.

Fertilizer type Advantages Disadvantages
Organic
  • Won’t burn lawns
  • Slow and steady nutrient release
  • Contains a wide range of trace minerals and balanced nutrition for your grass
  • Helps soil life by breaking down soil matter and encouraging aeration from earthworms
  • Less nutrient release in cooler temperatures
  • More expensive
  • Dependent on microorganisms in the soil
  • Animal manure or other homemade organic fertilizers may not be completely broken down, causing harmful runoff
Inorganic
  • Commonly available
  • Formulas varied for exact lawn needs
  • Works quickly
  • Inexpensive, even for higher quality brands
  • Shorter life span
  • Can affect soil fertility/deteriorate soil
  • Potential to burn lawn
  • May cause chemical runoff
black soil in man hand closeup outdoor

The best time to use lawn fertilizer

Much like choosing the right fertilizer for your lawn, the best time to fertilize your lawn depends on a number of factors. In addition to factors like grass type or climate, your specific lawn may need more or fewer fertilizer applications than your neighbors. Testing your soil once or twice a year can help you determine if you need to do another fertilizer application. Additionally, if your grass is yellowing, a pale green color, or not growing, it may be time to apply some lawn fertilizer.

Ideal grass temperature Examples of grass types Location commonly grown When to apply fertilizer
Cool-season
  • Kentucky Bluegrass
  • Tall fescue
  • Perennial Ryegrass
  • New York
  • Oregon
  • Minnesota
  • Inland California
Fall, though you can do a follow-up application in early spring if your lawn needs it.
Warm-season
  • Bermuda
  • Zoysia
  • Centipede
  • Florida
  • Arizona
  • Southern California
Early summer—You can add a second application in August to promote healthy growth before these varieties go partially dormant in the winter months.

Lawn fertilizer application

How you fertilize your lawn greatly depends on the type of fertilizer you’re using and the size of your yard. There are several types of lawn fertilizer applicators that spread an even layer of fertilizer onto your lawn. You may also sprinkle fertilizer by hand on small areas or if using an organic fertilizer such as compost, which may get stuck in a fertilizer spreader. Although the size of your lawn will affect the time it takes to fertilize it, you should set aside several hours to fertilize your lawn completely. Choose between these types of fertilizer applicators:

  • Handheld applicators—Great for smaller areas like patchy spots or small lawns, handheld applicators are similar to a broadcast spreader but much smaller. They allow you to turn a crank handle and spread small amounts of fertilizer.
  • Push-behind drop spreader—Drop spreaders deposit fertilizer in neat rows directly below the spreader as you walk. Since the fertilizer is evenly spread, drop spreaders can take longer to use on larger lawns.
  • Broadcast spreader—Similar to a drop spreader, broadcast spreaders are usually pushed from behind. However, they have various settings and a rotatory device that spins faster the faster you walk. Your speed controls how far the fertilizer is spread in a crescent formation from your spreader.
  • Liquid applicators—Used only for fast-release liquid fertilizer, liquid applicators include spray pumps and hose nozzles that mix concentrated fertilizer in with water.
Male hand watering garden with pressed spray

Safety while using lawn fertilizer

Most lawn fertilizers are not concentrated enough to cause instant harm, but you still want to make sure you handle them safely and correctly. Be sure you read all directions on both your spreader and the fertilizer bag before beginning. This will ensure you know how to correctly operate the spreader and will let you know if your fertilizer needs to be mixed with anything. Once you’ve covered your lawn, sweep off fertilizer granules from hard surfaces like sidewalks or roadways to prevent runoff when watering.

My lawn is fertilized, what next?

Once you’ve determined which fertilizer is best for your lawn and properly applied it, you might have questions about watering, mowing, or safety after fertilizer applications.

When should I water the lawn after fertilizing?

After fertilizing, you should lightly water the entire lawn to help flush the nutrients into the soil. After the initial watering, water as you normally would for your grass type.

When can I let my pets back onto the lawn?

Your fertilizer label should give you an exact time frame of when it will be safe to allow pets into the yard. Fertilizers that have not been absorbed by the soil can cause vomiting, diarrhea, and other serious illness in pets. If you’re unsure if your fertilizer is safe, look for a variety that is kid- or pet-friendly.

When can I start mowing my lawn after fertilizing?

If you use a granular bead fertilizer, you should be able to begin mowing again after the first watering or rainstorm. This allows the granules to sink into the soil.

 
Blue fertilizer in brown bag on green grass

Lawn fertilizer: DIY or hire?

With so much technical information and chemical involvement that goes into fertilizing your lawn, it’s a good idea to leave it to the professionals. A professional lawn care service like TruGreen will determine the best type of fertilizer for your lawn, as well as how much needs to be applied.

DIY

  • Cheaper up front: It may be cheaper to purchase fertilizer from your local lawn and garden store and spread it yourself.
  • A lawn to be proud of: If you can get the perfect nutrient formula for your lawn, you can certainly be proud of your hard work.
  • The downside: Alternatively, if you do end up burning your lawn, you will have to figure out how to fix the problem on your own.

Hire

  • Specialized knowledge from experts: Professional lawn technicians know how to test your soil and create the right mix of fertilizers for your needs.
  • Continual lawn care: Once your lawn is properly fertilized, the professionals can keep it looking great with regular appointments.
  • Problem correction: Companies like TruGreen offer a Healthy Lawn Guarantee®◆ to ensure you get the lawn you want. If the fertilizer burns your grass, they’ll accept responsibility and get it fixed.

TruGreen: Keeping your healthy lawn year-round

Fertilizing your lawn is just one part of a complete lawn care routine all year long. Investing in a professional lawn care company can help you not only build a beautiful lawn but maintain it. The best part is you won’t have to waste your time trying to figure out fertilizer labels and amounts for your lawn. Providers like TruGreen offer a range of lawn care service packages to take care of the fertilization or your yard, and much more.

TruHealthSM Lawn Plan TruCompleteSM Lawn Plan TruSignatureSM Lawn Plan
  • Lime
  • Pre-emergent and targeted weed control
  • Fertilization
  • Lime
  • Pre-emergent and targeted weed control
  • Fertilization
  • Aeration
  • Lime
  • Pre-emergent and targeted weed control
  • Fertilization
  • Aeration
  • Tree & Shrub Plan

All three packages include the Healthy Lawn Guarantee and Healthy Lawn Analysis®✦.

Why choose TruGreen for your lawn fertilizer needs?

At House Method, we suggest TruGreen as a professional lawn care provider to take care of fertilizing your lawn. As America’s #1 lawn care company, they have branches in many major cities—including Tampa, Austin, and Houston—across 47 states, so there’s likely one near you.*

Not only are their technicians experts in the lawn care field, but they provide the localized service your lawn needs. They’ll be able to determine what types of fertilizers work best for your climate, soil type, and grass type. Other reasons we recommend TruGreen include:

  • Guaranteed results—The Healthy Lawn Guarantee ensures that you’re satisfied with the technician’s work and are happy with how your yard works. If not, they will come between regularly scheduled appointments to fix the problem.
  • Healthy Lawn Analysis—Your lawn fertilization service starts with an analysis of your lawn to figure out what’s missing from your soil.
  • Care that’s tailored to your lawn care—Your lawn is a unique landscape, and TruGreen provides the individualized care necessary for it to thrive.

If you’re interested in learning more about TruGreen’s lawn fertilizer and lawn care services, give them a call at 888.535.3193 or fill out the online form for a free quote.

green short thick Bermuda grass lawn background

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*America’s #1 lawn care company based on U.S. market share of professional lawn care companies. 2017 NorthStar Partners U.S. Share Tracker. Purchase of full lawn plan required for Healthy Lawn Analysis, which is performed at the first visit. Guarantee applies to full plan customers only.

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