How to fertilize lawn?


How Often Should You Fertilize Your Lawn?

If there’s one scent that’s most reminiscent of spring, it’s the smell of fresh grass.

In order to have a lawn that is vibrant, green and ready to sink your bare feet into, however, you must take care of it. A turf maintenance program aims to produce attractive grass that is healthy and able to withstand the rigors of everyday use.

A key element of this program is fertilization. But what does fertilization do and how often does the lawn need it? How often you should fertilize your lawn is based on a number of important factors.

Types Of Fertilizer

Turf fertilization contributes greatly to lawn color, density, uniformity and growth. Properly fertilized grass better competes with weeds, crowding them out. Well-maintained lawns also recover from damage caused by environmental stresses like drought much faster than neglected or improperly fertilized lawns.

Fertilizer comes in many blends of three important nutrients—Nitrogen (N), Phosphorus (P) and Potassium (K). These nutrients are usually listed on the fertilizer bag in N-P-K order.

Using the right blend of N-P-K for your lawn takes an understanding of the specific needs of your turf, as well as your soil. Testing the soil can be a great first step in knowing what nutrients your lawn needs — and what your turf fertilization program should include. Outback can do this for you or you can send a soil sample to a local university extension service for testing.

How Often To Fertilize

A typical lawn care program in Idaho Falls includes five fertilization treatments, two of which include some form of weed control, usually a pre-emergent herbicide in spring and a post-emergent herbicide in summer.

The full, five-step program is crucial to a truly healthy lawn.

One fertilization treatment each year really doesn’t do enough to help give the lawn the nutrients it needs; you wouldn’t notice a real positive difference.

It takes multiple applications. Even four treatments are just OK. That fifth treatment, which is usually done around late October, is one of the most important for winterizing the lawn and helping it come back rejuvenated the following spring.

Also, consistency is key with turf fertilization. Caring for the lawn one year and then ignoring it the next doesn’t mean you won’t have problems such as weeds slowly start to creep up. A lawn consistently fertilized will slowly get to a prime and healthy growing place.

Timing Is Everything

The timing of each fertilization treatment, as well as using the right amount of nutrients, is also crucial to a solid turf fertilization program. You don’t want a bunch of iron or nitrogen to hit the turf at one moment in the growing season and then not at any other.

Using a slow-release nitrogen source is also important at certain times of year (like this spring which is a bit early this year) because it does pretty much as it describes — releases that nitrogen slowly into the lawn, providing that needed green up and growth burst as spring settles in.

Lawn Fertilization At Its Finest

As you can see, turf fertility is a detailed process that involves adequate knowledge of your turf types, your soil condition and understanding weather and other conditions that impact fertilization treatments.

Outback can take care of all of the details for you and provide a custom turf fertilization program that can make your lawn the envy of the neighborhood. We can also include a soil test in your lawn analysis.

Contact our experts at 208-656-3220 or fill out the contact form to set up a no-obligation meeting with one of our team members to discuss your lawn challenges and needs.

Should I Fertilize My Lawn in the Fall? Yes! Here’s Why and How.

Our toes love gliding through our lush, green grass. But did you know our lawn does far more than just look and feel good?

Lawns also improve air quality, reduce heat by 20 to 30 degrees and generate oxygen. That’s another reason why we need to ensure lawns stay healthy. So they can continue creating these perks.

One of the best ways to keep grass vibrant on the surface and healthy down into their roots is to fertilize. And right now is the most important fertilization of the year – not spring!

Learn why fall is the year’s most important lawn fertilization– and everything you need to know about the best time to fertilize. Should you mow first? Wait until after it rains? Or wait until the best time of day to fertilize the lawn?

Why Fertilize Your Lawn in Fall – The Best Fall Month and Time of Day to Fertilize

Summer heat is stressful on our lawns. Fall’s cooler temperatures provide the perfect setting for lawn to regain strength.

Fall is the best and most important time to fertilize your lawn because:

• Fall’s morning dew delivers moisture to help turf absorb the fertilizer.

• The grass has a chance to build stamina before a chilly winter.

• Supporting root growth in fall leads to a healthier, greener lawn in spring.

While fall is naturally good for feeding our lawn, you can deliver an extra oomph by fertilizing as best as you can, too.

When in fall should you apply fertilizer to your lawn?

Apply fall lawn fertilizer 2 to 3 weeks before the ground freezes.

To find an exact date, look for the first frost date in your area. That date is typically a good time to fertilize since the ground hasn’t frozen yet.

More generally, mid-October is a good time to apply lawn fertilizer.

Is there a best time of day to fertilize your lawn?

Sure is! The best time of day to fertilize is in the morning or early evening. Both times avoid the warm daytime temperatures that work against fertilizer.

When to fertilize lawn after mowing?

Start with a clean slate by mowing the lawn right before you fertilize. Leave some grass clippings behind to help the roots.

Should lawn fertilizer be applied before rain?

Never fertilize lawns before a heavy rain to avoid runoff, so be sure to check the forecast before you start. And if it recently rained, let the grass blades dry before fertilizing.

When should I fertilize my lawn??

I n my experience, I would not recommend that you work with one of the national providers, as they often do not maintain their customers. You can quickly see the poor reviews the national companies have with a quick online search.

To the contrary, I would recommend that you look for a locally owned company that only does lawn fertilization. I would not recommend that you work with a company that also does lawn mowing, as turf fertilization and weed control is its own discipline.

No doubt about it, the companies you have hired to mow and fertilize, are often not as good as the companies that focus solely on lawn spraying and fertilization.

When you hire a good company they will handle the necessary applications to keep the lawn in its best performing shape. Typically a comple lawn program will consist of 4-6 timly applications per year.

So, What’s the Bottom Line?

The best bet is to work with a Pro. Yes you can fertilize on your own, it can even be quite fun, but is not always an easy task. If you want to do it on your own be sure to check know the best fertilizers for your lawn.

This plan works well for southeastern climates, but if you live in a warmer climate such as Florida you will want to read our guide for caring for St. Augustine turf.

Use this fertilizer guide to fertilize to schedule your own fertilizer program, or in to better inform yourself when you hire the pros. GreenPal is a great source for lawn care professionals, take a look the next time you need to hire someone for your lawn care needs.

How To Apply Weed And Feed Lawn Fertilizer

Weed and Feed Fertilizer is an option to consider when you want to fertilize your turf in the spring and control weeds with the same application.

In this FAQ, Christina Burton, Horizon’s Maintenance Channel Manager, discusses the two main types of Weed and Feed and shares application tips that will help you get a healthy, weed-free lawn.

Weed And Feed Fertilizer Application – Video Transcript

If you want to fertilize your turf in the spring and also control weeds, you would wanna consider a Combo Fertilizer. Or a lot of people know this as a Weed and Feed.
So the way to choose a Weed and Feed is to really first ask the question, “Are you trying to prevent weeds from growing? Or are you trying to control ones that are already there in your lawn and you want to remove them?”
If you want to prevent weeds, you need to use a product that has pre-emergent on it. And what it really does is when you put down the fertilizer and its got the pre-emergent on it. And you water it in, that’s really important, you end up creating this barrier underneath the soil. And these weed seeds, as they try to emerge, they hit this chemical barrier and they die before they can sprout.
A post-emergent on the other hand, you’ve already got weeds in the lawn and it’s really important that this product sticks onto the actual leaves of the weeds. If the product doesn’t stick there, getting washed off into the ground doesn’t do anything. Because that’s not the way that that chemical is taken up. It doesn’t take it up through the roots. It’s gotta go through the leaves.
So a couple important things to note:

  • First of all, you wanna make sure that you water just lightly prior to applying the product so that the leaves are wet and the product will stick to the leaves.

  • And then you’ll also want to make sure that you shut the irrigation off so it doesn’t get washed off. It has time to be absorbed and taken down to the roots. That’s the way it carries down the chemical.

And then another common mistake is that folks will think that they should mow the lawn prior to. That that will be better. They’ll get the weeds partially mowed down and then apply it. But the problem is if you come in and chop these weeds off, you’ve gotten rid of a lot of the surface area of the leaves that’s going to take up the chemical. So your chemical actually works not as well.

So again, make sure you water it first, have the product stick to the leaf, turn the irrigation off so it doesn’t get washed off for 24 hours, and try to not mow for about 2 days before and 2 days after applying the product.

Why weed and feed isn’t your best option

Weed n Feed sounds like the perfect product, right?

A two in one lawn care product that identifies the two key areas we usually focus on when caring for our lawns – weeding and fertilising. Sounds like the perfect product, right? Well here at Lawn Solutions Australia we’re here to separate the spin from the real facts so you get the right results when looking after your grass.

What is Weed n Feed?

Weed n Feed normally consists of a broadleaf herbicide and some sort of fertiliser component. It comes in a bottle which you attach to your hose and spray onto your lawn. The goal being to kill your weeds and to give your lawn a boost at the same time. Unfortunately, the results aren’t usually what you are hoping for.

Herbicide Component

The active constituent in Weed n Feed is Dicamba. The rate of Dicamba present in Weed n Feed bottles is very low and isn’t very effective on most broadleaf weeds (hence the very cheap price of Weed n Feed) and you will usually need 2 or 3 applications to get a result.

Dicamba cannot be used on Soft-Leaf buffalo lawns, as it will cause the lawn to die back and turn yellow. This greatly limits the products use in the domestic market as a lot of home lawns in Australia are soft leaf buffalo.

Fertiliser Component

Weed n Feed adds very little nutrient value to the grass. The fertiliser component mainly contains Nitrogen and Iron, which will give the plant a short boost of green colour, but usually contains zero Phosphorus and Potassium, so it does virtually nothing for the root strength and development of the plant. Which means it is hardly a fertiliser at all.

In conclusion…

Weed n Feed is not the best solution when undertaking fertilising and weed control on your lawn. Lawn Solutions Australia recommends using a broadleaf herbicide and a lawn fertiliser separately to get the best results. Make sure you use a broadleaf herbicide that is safe to use on your turf variety before application and that it is effective against the types of weeds you are spraying for. Follow this up with a slow-release granular fertiliser like Lawn Solutions Fertiliser, which will get the best results for the overall health of your lawn for longer periods of time.

Check out the Lawn Solutions Australia lawn care page for more helpful tips and advice here.

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How to Use Lawn Fertilizer

Grass-cycling. If you’re tired of bagging grass while you mow, we’ve got good news. To help your lawn stay greener year-round, you can leave the grass clippings on your lawn. When grass clippings break down, they provide your lawn with beneficial nutrients. While you don’t need to buy a new mower blade, it doesn’t hurt to install a mulching blade so that the grass is cut into smaller pieces. Learn more about recycling grass clippings here.

Using a spreader. When applying lawn fertilizers, always use a lawn spreader. Never spread product by hand! A broadcast spreader with a side-shield feature like the EdgeGuard® feature is great for most lawns. This makes application along the lawn’s perimeter easy by shutting off half the spreader flow, so product is only applied on the lawn and not on non-lawn areas like the driveway, sidewalk, or landscaping. A drop spreader is another option for small spaces because the application area is much narrower. Learn more about which spreader is right your yard by reading this article.

Fill the spreader hopper with your lawn fertilizer, then set the spreader to the recommended setting listed on the product package. If the product package does not provide a spreader setting, it is not intended for lawn use.

Applying grass fertilizer. Now you’re ready to apply. Feeding the lawn is as simple as mowing it, and as easy as walking at your normal steady pace. Just follow these guidelines for easy application and even coverage.

If you’re using a broadcast spreader, feed the entire perimeter of your lawn first. Engage the side-shield, which blocks off one side of the spreader to keep the product on the lawn and out of gardening beds and off driveways and sidewalks. Next, fill in the middle by turning off the side-shield feature and walking back and forth in straight lines. To get even coverage, overlap slightly on each pass by moving over 2 steps before you begin the pass.

When using a drop spreader, start by applying 2 header strips at opposite ends of the lawn to create a turning area. Next, fill in the rest of the lawn by applying the fertilizer back and forth in straight lines perpendicular to your header strips. To ensure you get even coverage, be sure to overlap the wheel tracks by about half a foot (there are arrow marks on the spreader hopper to help you overlap properly).

After you’ve finished feeding your lawn, return any unused product to the bag and store it for future use.

Step 1

Failure to test the soil

Test the soil

Family Handyman

You can collect your own samples by randomly pulling 10 to 12 individual soil samples from your lawn to a depth of 3 to 4 in. Make sure there is no vegetation or excessive root mass in the soil sample. Mix together the soil samples and put about a cup of this mix in a plastic bag. Write your name on the bag and send it off for testing.

“I can’t tell you how many times I’ve talked to a professional or a homeowner who has never tested their soil. Big mistake!”

When I’m asked to help bring a homeowner’s lawn back to life, the first thing I do is to make sure they have their soil professionally tested. Think of it as a checkup for your lawn. The results will provide important information that will help determine what type of grass fertilizer you should use and how often you should apply it.

You can collect your own samples by randomly pulling 10 to 12 individual soil samples from your lawn to a depth of 3 to 4 in. Make sure there is no vegetation or excessive root mass in the soil sample. Mix together the soil samples and put about a cup of this mix in a plastic bag. Write your name on the bag and send it off for testing.

Most often, a soil test will focus on measuring major nutrients like phosphorus (required for good root development) and potassium (needed to remedy environmental stresses). If your soils are lacking in these major building blocks, your lawn will suffer.

Another important piece of information received from a soil test is your soil’s pH. Most lawn grasses like a soil pH in the range of 6.5 to 7.0. If your lawn’s soil pH is too low or too high, the fertilizer you use may not work very well. Soils with a low pH, like 5.5 or 6.0, will require applications of lime to “sweeten” the soil. Soil pH values above 7.5 will require soil sulfur or a lawn fertilizer containing sulfur to bring the pH down.

If your soil test results recommend adjustments to correct nutrient or pH issues, it’s wise to test annually until the problems are corrected. If your soil test does not reveal any issues, test about every three years to monitor the health of your soil.

The best time to test your soil is early spring just before your lawn comes out of dormancy. Don’t collect samples after grass fertilizing. This will skew the results. And don’t use do-it-yourself kits! They may be less expensive, but they aren’t very accurate. Your county extension office, reputable garden center or local university can help you test your soil accurately, interpret the results and then offer solid recommendations for fixing any soil problems.

12 Tricked-Out Lawn Mowers You Need to See

Lawn Fertilizer Tips: When And How To Apply Lawn Fertilizer

Some of our fondest memories are connected to our lawns. It’s a great place to roughhouse with kids and dogs, entertain guests, or simply sit and enjoy life. To grow a beautiful lawn that you’ll be proud of, you need to develop a proper maintenance schedule which includes fertilization. Read on to find out about feeding lawns so yours will always look its best.

When to Put Fertilizer on Lawns

All lawns need fertilizer in early spring when the grass begins to green up. Your fertilization schedule for the rest of the season depends on the type of grass in your lawn, the type of fertilizer you use, and your climate. Most lawn seed is a mixture of several different types of grasses, and both spring and fall fertilization are appropriate.

The label on a bag of lawn fertilizer will recommend a schedule based on the type of fertilizer it contains. The label is your best guide to how often to apply the product and how much to use. As long as you don’t overdo it and avoid fertilizing in the hottest part of summer, your lawn should thrive.

How to Apply Lawn Fertilizer

There are several ways to apply lawn fertilizer. Using a spreader provides more even coverage than fertilizing by hand. Hand fertilizing often results in burns where the fertilizer is concentrated and pale areas that don’t get as much fertilizer as they should.

Broadcast or rotary spreaders are easy to use and don’t cause striping like drop spreaders. The advantage to drop spreaders is that there is no chance of overthrow getting fertilizer on streets, sidewalks or driveways. With a drop spreader, you have to make two trips over the lawn at right angles. For example, if you make your first trip over the lawn in a north-south direction, the second trip should run east to west.

After applying the fertilizer, water the lawn thoroughly. Watering rinses the fertilizer off the grass blades so that they won’t burn, and it allows the fertilizer to sink down into the soil so it can get to work. Keep kids and pets off the lawn for the amount of time recommended on the label, which is usually 24 to 48 hours.

Types of Fertilizer to Use on Lawns

Here are the basic types of fertilizer to use on lawns:

Slow-release – You don’t have to use slow release fertilizers as often, but they are usually more expensive.

Fast-release – You get quick results with a fast-release fertilizer, but you have to apply them in smaller amounts and more frequently. You can burn your lawn with a fast-release fertilizer if you use too much.

Weed and feed – Try to identify your weeds before using a weed and feed product and make sure your weed is listed on the product label. Take special care around trees, shrubs and garden plants.

Organic materials such as compost and manure – The essential nutrients aren’t as concentrated in these types of materials, so you have to use a lot. Compost or dry manure before applying it to the lawn, and be aware that some manures, particularly horse manure, may contain weed seeds.

Liquid fertilizers – These aren’t recommended because they are hard to apply evenly and require frequent applications.

Additional Lawn Fertilizer Tips

  • Water the lawn a few days before you fertilize to make sure it isn’t suffering from drought stress.
  • Make sure the grass blades are completely dry when you fertilize the lawn to avoid burns.
  • Fill the spreader on the driveway or on cement so that you can sweep up spills easily.


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I had a landlord once that was a lawn fanatic. I had to keep that sucker lush, green, and growing from early spring through frost. Ordinarily that probably wouldn’t be a problem, except it was huge, it was in a desert, and there wasn’t any in-ground sprinkler systems. Because of this the soils were extremely poor as well, and I found myself constantly questioning when to apply lawn fertilizer.

Coincidentally I used to cringe at fertilizer prices for the size I had to cover, and dreaded spreading it since I also had to manage to keep both dogs and children away for the set time period. However, since owning my own property (with a healthy size, but much more manageable lawn), I’ve learned there are a few techniques you can apply to work smarter, not harder, to keep your grass lush and growing green by knowing when to fertilize a lawn.

If you take pride in your lawn, then you too know that there is certain amount of maintenance involved with lawn care, but you don’t have to break your back doing it. Read on to find the answer to how often should you fertilize your lawn.

Table of Contents


Fertilizer adds the essential nutrients needed to keep your grass growing. Growing grass uses up the ‘foods’ found in the soil, and if they are not replaced somehow, that food eventually runs out and your grass will begin to fade and stop growing as well.

Ideally (and in the perfect gardening world), whether you have laid sod, grass seed, or have inherited a lawn with your house- the topsoil the grass roots are growing into are at least four or more inches deep and are a healthy mix of decayed organic material and sand for good drainage. You also have the perfect amount of rain to prevent nutrient run-off, and your grass grows a uniform amount each month before needing a trim. If this is the case, then you most likely have everything you need to feed your lawn without adding fertilizer by leaving behind some grass clippings every so often during cutting.


Before determining when to fertilize, you need to determine what kinds of grasses you have to optimize the adding of new nutrients. Cool season and warm season grasses grow differently, take water differently, and consequently take up nutrients differently. Determine your grasses and growing seasons, and then pick your fertilizer based on needs.

When to Fertilize Cool Season Grasses

Cool season grasses, as expected, grow in cooler climates. They stay mostly green year round where they have cold winters, and cool (but not hot) summers. Growing seasons that average between 60-75 degrees that include cold winter months are ideal. Many lawn owners ask when to apply winter lawn fertilizer, but for winter lawns you will want to fertilize in fall.

These grasses include:

  • Kentucky Bluegrass
  • Fine or Tall Fescue
  • Bentgrass
  • Perennial and Annual Ryegrasses

Fertilizing cool season grasses should occur three times a year, twice in the fall, and once in the spring. Fall feeding is the most important time to fertilize, and should occur about six weeks before the first frost. Generally early to mid September is a good time to consider in order to let grass roots take in the extra nutrients as they ready to slow their growth for the winter, and again after frost, usually sometime in November to help with winter feeding. Come spring you can also spread fertilizer lightly again after the first flush of growth occurs to avoid overfeeding, which can result in excessive top growth and shallower roots. .

What type of Fertilizer to Use

Nitrogen is the most important nutrient for grasses and should be spread at a rate of one pound per 1000 square feet of lawn, so you definitely want to use a nitrogen rich fertilizer such as a quick release nitrogen variety. You’ll also want to check your pH balance (soils should be slightly acidic), as well as phosphorus and potassium levels for adequacy to determine if you need to add sulfur for pH or other nutrients. These can be tested easily using a kit you can purchase easily online and at some garden centers.

Use the following link to calculate what you will need based on soil results.

When to Fertilize Warm Season Grasses

Warm season grasses grow best when the temperatures during the growing season average between 80 to 95 degrees, and go dormant in winter, turning brown for around three to five months depending on your climate. Dormancy occurs after the first frost.

Popular warm season grasses include:

  • Bermuda
  • Buffalo
  • Bahia
  • Zoysia
  • St. Augustine
  • Centipede

Warm season grasses are, as a rule of thumb, much easier to maintain than cool season varieties. They only need a feeding once in the spring after they have come out of dormancy, but are more easily damaged by fertilizer- and so waiting to spread nutrients later is better than earlier. If you are unsure if your grass is fully out of dormancy, consider waiting until you have cut it at least three times to be safe.

However, you can also feed periodically throughout the growing season and into fall if you feel your lawn will benefit from it. Determining if your lawn needs an extra boost from multiple feedings is as simple as running a soil test to see if nutrients are lacking, or if your grass is looking less than vibrant despite applying proper watering techniques. Warmer climates tend towards a quicker growth of vegetation, meaning more nutrients are used more rapidly.

What Type of Fertilizer to Use

Like cool season grasses, warm season grasses benefit the most from nitrogen rich fertilizers. Run a soil test to determine potassium and phosphorus rates as well, and see if you have a healthy pH. Knowing this will help you calculate your lawns particular needs and which

Fertilizing After Seeding or Overseeding

Fertilizing seeded areas should be avoided until the grass is well established. Many fertilizers contain a herbicide that keeps seed from germinating, and you won’t be doing your new seed any favors by attempting to ‘feed’ it so early on.

Once seed has become established, fertilizing is important to help get grass the nutrients it needs to get deep healthy root. But even so, do not fertilize until at least 4 weeks after germination to ensure all seed has taken root. And be sure to use a lower nitrogen feed for the first few applications so as to not give the weeds in the area a chance to choke out your newly forming grass roots. Instead, apply a general balanced fertilizer.

Fertilizing New Lawn Sod

New turf, or sod, already has a healthy root system started, and so after laying your lawn, fertilizing is an important step to take to keep it growing and becoming established in the soil beneath the initial layment. First applications should occur at 4 weeks, and again at 8 weeks after instillation dates. After that a half pound of nitrogen every 1000 feet every four weeks is suggested until roots have grown well into the topsoil.

Fertilizing and Weed Killer

Just like all fertilizers can be different, so can weed killers, so it really is recommended to treat your lawn with both separately rather than in a combined application. However, if you want to go this route, there are a few helpful steps to take to make your application a success.

Granular combinations are more effective for both feeding and killing unwanted vegetation due to it’s times release into the soils. It washes away less easily, and gets more to the roots, where it is needed. Be sure to apply after mowing the lawn that takes the heads off of the majority of your weeds, and makes them more susceptible to uptake the poisons that will eradicate them. Also avoid watering heavily after initial spreading. Instead, sprinkle with water lightly before and after to ensure grains begin to dissolve.

Lawn Fertilizer Troubleshooting

By following the above guidelines you should be well on your way to a healthy lawn, but for further help, remember a few key things during application so you aren’t asking yourself about fertilizer amounts, weather, or if you should feed before or after mowing the lawn:

Do not over apply your fertilizer

Do not over apply your fertilizer. You do not want to burn out your grass. Even a little provides new nutrients to your grasses.

Do not apply fertilizer if rain is in the forecast.

Do not apply fertilizer if rain is in the forecast. You want it to get to the roots, and not be washed away by too much water.

Apply fertilizers after mowing your lawn

Apply fertilizers after mowing your lawn, and not before in order to allow it time to absorb before the next cutting.

Mark Your Calendars!

Keep in mind that to properly fertilize your lawn you will need to make sure you have knowledge of your grasses to get started. I always struggled with keeping my lawn looking the way I wanted until I began to follow the simple fertilizing steps outlined above. To recap, remember you need to start with knowing what type of grasses you are growing.

  • Know your grass
  • Pick your dates
  • Choose a nitrogen rich fertilizer
  • Apply correctly
  • Fertilize newly seeded lawn or sod correctly
  • Use granular weed and fertilizer combos
  • Do not over apply or overwater!

Have any helpful hints and success stories? Comment below! Any questions? Feel free to ask and we will get back to you! And, as always, please share!


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Water, fertilizing and mowing lawn-care tips

Pale, yellow-green grass is a tip-off that your lawn needs more nitrogen, the key ingredient in fertilizer. Using the right fertilizer at the right time is the quickest and easiest way to provide that nitrogen so that you lawn can better withstand pests and extreme heat and cold.

Where to begin? A good first step is to obtaining the proper soil pH through a soil test. Getting the right pH level (usually by adding lime) increases the effectiveness of any fertilizer. It is better to invest in lime in the spring rather than fertilizer.

Use a fertilizer formulated specifically for lawns and follow the directions on the label. That includes using the spreader the label stipulates so that you can use the recommended setting. But you’ll still be faced with a plethora of choices. Using the wrong kind in the wrong way can hurt more than help. Indeed, too much fertilizer can pollute the ground and encourage lawn pests. Here’s what’s available and how to apply it:

Kinds of lawn fertilizers

There are three main types. The major difference is in how quickly their nitrogen gets to the grass roots.

Natural organic fertilizers include manures, composts, and agricultural byproducts that might otherwise be wasted (see our Web site,, for composting tips). Natural organics contain relatively low amounts of nutrients that are released slowly, so using too much probably won’t damage the lawn. But you’ll need to apply more of them. What’s more, some may include weed seeds. Those that don’t include alfalfa, blood meal, and soybean meal.

Slow-release chemical fertilizers are more concentrated than natural organics and easier to apply. They’re also unlikely to damage lawns if applied too liberally. Half or more of the nitrogen in brand-name lawn fertilizers is typically in this form, called water-insoluble nitrogen (WIN). These fertilizers don’t produce an immediate effect, but that’s usually better for the grass.

Fast-release fertilizers are one way to green-up your lawn quickly. They’re relatively concentrated, inexpensive, and easy to apply. But putting down too much or spreading it over a damp lawn in warm weather can burn the grass. Because their nutrients are used quickly, you’ll have to apply them more often.

When to fertilize

If you fertilize once a year, do it in September for cool-season, Northern grasses, and early June for warm-season, Southern grasses. Otherwise, make two to three applications in fall, one month apart, and one in spring for cool-season grasses; three applications are needed during the summer for warm-season grasses.

How much

Lawn fertilizers contain nitrogen and, usually, phosphorus and potassium in that order. You’ll know how much a fertilizer contains by checking its label. A 100-pound bag labeled 20-0-0 has 20 pounds of nitrogen, and no phosphorus or potassium, for instance.

Lawns typically need only 25 percent as much phosphorus and 50 percent as much potassium as they do nitrogen. So don’t apply phosphorus or potassium unless it’s needed. A soil test is the only way to tell (search the Web using the words “soil testing “).

Recommendations for lawn fertilizers are usually given in actual nitrogen over a given area. Experts recommend no more than 1 pound of actual nitrogen per 1,000 square feet for each application. Once you know a fertilizer’s nitrogen concentration, calculate how many times that first, nitrogen-percentage number in the fertilizer mix goes into 100, then apply that many pounds of fertilizer per 1,000 square feet.

For example, figure on using 5 pounds of 20-5-10 fertilizer, 10 pounds of 10-2 1/2-5 and so on. The total actual nitrogen applied per year should be 3 to 5 pounds. To double-check your calculations, use Purdue University’s Turf Fertilizer Calculator (


Returning mulched clippings to your lawn rather than bagging and disposing of them reduces the need for lawn fertilizer by 30 to 50 percent. That equals roughly 2 to 2.5 pounds of fertilizer per year to put down 4 pounds of actual nitrogen.

Calibrating a drop spreader

Fill the spreader with fertilizer, note its setting, and operate it over 50 feet with a collection pan or strip of plastic sheeting beneath it. Weigh the amount of fertilizer that fell on the pan or strip. Calculate the square footage you covered (50 feet times the spreader’s width in feet). Then use that as a guide to how much the spreader will deliver over the 1,000 square feet specified on fertilizer labels. For example, if the spreader dropped 1 pound of fertilizer per 100 square feet, it will drop 10 pounds per 1,000 square feet at that setting. Increase or reduce the amount delivered as needed.

When to Fertilize Your Lawn

By Lance Walheim, The National Gardening Association

When and how often you should apply fertilizer to your lawn depends on the type of grass you grow. Grasses need nitrogen and other nutrients during their seasons of active growth, and they grow best with an even supply. Fertilize grasses when it’s naturally dormant, and you’re wasting fertilizer. Space your applications too far apart, and your grass grows fine for a while, then slows down, and then speeds up again with the next application.

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Warm-season grasses, like Bermuda grass and St. Augustine grass, grow rapidly in warm weather. Generally, you need to feed warm-season grasses from late spring to early fall. If you feed too early in spring the nitrogen likely promotes rapid growth of cool-season weeds. You don’t want that. If you fertilize too late in fall, the grass is likely to be less hardy as it enters cold weather and more susceptible to winter injury.

Cool-season grasses, such as Kentucky bluegrass and tall fescue, grow most vigorously in the cooler months of fall and spring. In mild-winter climates, such as the deep South and southern California, cool-season grasses can grow throughout winter. So the most important time to feed cool-season grasses is in fall and spring, and sometimes in winter. Fall, in particular, is a very important time to feed cool-season grasses, keeping them growing longer into cool weather and providing the reserves needed for quick green-up in spring. In fact, you also should avoid fertilizing cool-season grasses too early in spring. You end up with overly lush top growth at the expense of root growth, and that can mean trouble. Besides, if you fertilize in fall, the lawn doesn’t need another application until later in the spring, anyway.

Even though cool-season grasses stay green, avoid fertilizing during the heat of midsummer. Growth naturally slows down in very hot weather, and applying fertilizer at that time can actually weaken the lawn. The exceptions are those lawns growing in far northern or high-elevation climates where the weather stays relatively cool all summer. You can feed lawns in those areas throughout the growing season

For maximum appearance, fertilize your lawn about once every six to eight weeks during their active-growth period. Simply break up the yearly requirement of nitrogen into the appropriate number of applications, say one or two in spring and two or three in fall for cool-season grasses, three over the summer for warm-season grasses.

If you’re not up for the higher-maintenance lawn (that is, frequent mowing), fertilizing once in spring and once in fall for cool-season grasses, and once in early summer and once in late summer for warm-season grasses, gives you a pretty nice lawn.

Got even less time? Fertilize cool-season grasses in fall and warm-season grasses in late spring. Just remember, no more than 1 pound of nitrogen per 1,000 square feet with each application.

Should I fertilise in Winter?

There are benefits to fertilising your lawn during winter, but it isn’t the same fertiliser that you would use during the months of the year where your lawn is actively growing. Once soil temperatures drop below 14 degrees Celsius your grass will start to slow down and go semi-dormant for the cool months ahead. This is a protection method warm-season turfgrasses use to protect themselves from the harsh conditions of winter. Because most grasses in Australia are warm-season varieties, they never really go fully dormant and will continue to grow but at a much slower rate. It’s for this reason, that they still have the capacity to take up some nutrients which will be beneficial for keeping them strong through winter.

Lawn fertiliser in most cases, have three key nutrients that are important to maintaining the health of your lawn, Nitrogen, Phosphorus and Potassium. Nitrogen is the largest component and is the one that promotes strong leaf growth. In the winter months though, leaf growth is minimal and no matter how much Nitrogen you throw at your lawn, it won’t react and establish any quicker than the temperatures allow. So, if you are going to fertilise your lawn in winter, you need to look at what it is your lawn needs to stay healthiest and strong when it is suffering from the cold.

The key ingredient you will find in increased amounts in most winter fertilisers is Iron. Iron helps to strengthen your grass and improve leaf colour. Provided you have fertilised in Autumn and have your lawn well prepared for winter, you will be looking at providing an additional treatment around July in most states. You can apply Iron Chelate which will help to get better iron uptake for better results without the Nitrogen promoting unnecessary growth.

It is important that you fertilise your lawn regularly throughout the year, with Autumn being the most important. A strong, healthy lawn leading into winter is the key to having a healthy lawn come out the other side.

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