How to Fertilize Your Lawn

Before you fertilize your lawn, consider these tips to get the best results, and the best bang for your buck.

Fertilizing your own lawn gives you a huge advantage over your neighbors who hire it out. That is, you have the benefit of waiting for the perfect conditions which will give you the best results.

Lawn care companies are running a business.  If you are on the schedule to get your lawn treated they will most likely fertilize your lawn even if conditions are not ideal.

Applying your own lawn treatments also saves money, and reduces the spread of fungus and disease that can enter your lawn through equipment used on someone else’s lawn.

Don’t be intimidated by the idea of fertilizing your own lawn.  Follow these tips to keep things simple and be on the way to your best lawn yet.

Best Conditions to Fertilize Your Lawn

1. Wait until your soil temps are warm enough in early spring before applying.  Fertilizer works best once the soil temperature reaches 55 degrees.  Don’t waste your time or money by applying too early.

To find average soil temps based on your specific location check out Green Cast Online.  It takes about 10 seconds to find when soil temps usually approach 55 degrees in your region.  This is when you want to apply your first treatment.

2. Fertilize your lawn when there is a light rain expected.  Since fertilizer needs to be watered in to be effective, wait until the forecast calls for a light rain.  Just be sure to avoid heavy rains that will cause the fertilizer to run off.

3. Avoid applying fertilizer during the heat of the day, hot spells, or periods of drought.  This could cause your lawn to burn.  Instead, apply in the morning or late afternoon and when your aren’t experiencing extreme weather conditions.

The Right Equipment

A good broadcast spreader is important, but you don’t need to spend a lot of money on professional grade models. The Scotts EdgeGuard Spreader is great for residential use.  It also keeps things easy since most fertilizers have recommended Scotts settings on the back.

At the very least, just make sure you fertilize your lawn using a broadcast spreader instead of a drop spreader since it does a better job dispersing evenly.

Fertilizer Application Rates (Method 1)

“Which setting do I set my spreader too?”.  It’s such a common question.  The funny things is the answer can be really simple.

As long as you’re buying common fertilizers you can find in the big box stores, just look at the back of your bag of fertilizer and set the dial to whatever they tell you to set it too.  If you’re looking to keep things really simple then this is the way to go.

But If you’re looking to achieve a higher level of lawn care success, then this isn’t the best method.

Some Problems With (Method 1)

1. Those recommended settings on the back of the bag of fertilizer are based on a specific lawn care program provided by the fertilizer companies.  These are the “step” programs you see everywhere.

Every company pitches their own step programs as being the best, but for the most part they all contain an early season pre-emergent herbicide (step 1)  , followed by a post-emergent (step 2), and then at some point they suggest fungicides, and insect control.

If you want to break away from the step programs, (and I suggest you do), then you need to have a better understanding of application rates.

2. Not all products have suggested spreader settings.  Especially with some of the best organic fertilizers.  Instead they’ll give you a recommended pounds per square foot.  For example Milorganite might suggest you apply 32lbs per 2500 square foot.  This information is confusing to someone relying on recommended spreader settings.

3. Other factors come into play when applying lawn treatments.  For example, walking speed. If you walk really quickly you’re going to cover more ground and have less product on your lawn. Walking speed isn’t considered when companies suggest spreader settings.

4. Lastly, and most importantly, recommended spreader settings are made under the assumption you apply the entire application in one shot.  In other words, you walk your lawn once.

It’s very hard to apply product evenly if just going over your lawn once.  Instead, you’re much better off dialing down your settings and broadcasting over your lawn at least twice, in opposite directions.

You would think that you could just set your spreader to half the recommended setting, and apply twice.

The problem with that is it would mean setting your spreader at very low settings.  These very low settings usually disperse at a disproportionately low rate, lower then half.  This means at the end of your second pass, you will still have fertilizer in your spreader.

Fertilizer Application Rates (Method 2)

A much better method for applying fertilizer is to think less in terms of spreader settings, and instead on one important question you need to answer.

The question you should ask before applying your fertilizer is “How much of this stuff do I put down, to get me 1 pound of nitrogen per 1000 square feet?” 

That question is important.  You want to apply 1 pound of nitrogen per 1000 square feet.  Any more and you could risk burning your lawn if using synthetic fertilizers.

Applying less is fine. In fact during the hot summer months I apply closer to 3/4 lb per 1000 square feet.  But to keep the math simple just stick to 1 lb per 1000 square feet for now.

This sounds complicated, but things will be clearer after looking at some examples.

Examples to Understand Fertilizer Application Rates

Let’s look at an example to figure out how we answer “how much of this stuff do I put down, to get me 1 pound of nitrogen per 1000 square feet?’:

If you have a balanced fertilizer with numbers 10-10-10, that means that bag of fertilizer contains 10% Nitrogen, 10% Phosphorus, and 10% Potassium.  That’s right, those numbers on the bag of fertilizer are percentages of macro nutrients N, P, K.

Check out this link for a full explanation of N P K.

But for now, all you need to know is Nitrogen (the first number) is going to help us answer our question: “How much of this stuff do I put down, to get me 1 pound of nitrogen per 1000 square feet?”

It comes down to this simple equation:

Preferred pounds of nitrogen per 1000 square feet / Percent of Nitrogen in the bag = Pounds per 1000 square feet of application. 

We know that our preferred pounds of nitrogen per 1000 square feet is 1.

We know that the numbers 10-10-10 are referring to percentages, therefor this bag contains 10% nitrogen (nitrogen is the first number).

In this case the numbers look like this:

1 pound / .10 = 10

In this example we need to put down 10 pounds of product per 1000 square feet and that satisfies our 1 pound of nitrogen per 1000 square foot rule.

Let’s look at another example:  In this case let’s take a bag that is made up of 15-6-0.  This means there is 15% nitrogen.

Again, we know that we want 1 pound of nitrogen per 1000 square feet.  So using the equation from above we take 1 pound and divide that by the percent of Nitrogen in the bag.  In this case the percent of nitrogen is 15%:

1/.15= 6.6

You need to apply 6.6 pounds of this product per 1000 square feet.  Make it simple and just call it 6 pounds.

It’s finally time to open your bag of fertilizer and get ready to pour.

Fill Spreader With Fertilizer

Using the example above, all you really know at this point is that you need to apply 6 pounds of product for every 1000 square feet, so now what?

Don’t worry, this part is simple. Once again, let’s look at an example:

If your lawn is 5000 square feet, and you need to apply 6 pounds of product per 1000 square feet, then you need to apply 30 pounds of product (6 pounds * 5). The formula looks like this:

Application Rate * (1000’s of square feet) = Pounds of product to put in spreader

In the example above:

6 pounds * 5 = 30 pounds

If you have a 40 pound bag of fertilizer simply pour 3/4 of the bag into the spreader and this will be 30 pounds.

At this point we now know how much product is going to be distributed over the lawn.

The only question you should be asking yourself now is “How do I apply 30 pounds of fertilizer as evenly as possible.”

That’s it, still no mention of spreader settings.  Just 30 pounds of fertilizer spread evenly across your lawn.

So, what’s the secret to getting a good even fertilizer application?

Dial Down and Divide

The key to an even fertilizer application is low spreader settings and dividing your lawn into sections.

Using our example we know we need to apply 30 pounds of fertilizer to our 5000 square foot lawn.

Of the total 5000 square feet, 2500 is in the front yard and the other 2500 is in the backyard.

Instead of putting the full the full 30 pounds in the spreader and doing the whole lawn at once, put half in and set a low spreader setting (1.5-2.5).

With 15 pounds in the spreader, walk the back lawn making straight passes.  Go straight down in one direction and then turn and go in the opposite direction.  You want to overlap so that the fertilizer is being broadcasted over the wheel marks from your last pass.

After completing one pass of the entire back yard, check inside the spreader.  How much fertilizer is left?

This is when you have to use your judgement and start making adjustments.

If barely any fertilizer was used, turn the dial up a little bit to a higher setting before going over the back lawn again.  If half was used, then don’t touch the dial.  Maybe more than half was used, then turn the dial down a little.

When you go over the back lawn for the second time go perpendicular to the first pass.

Once finished going over the back lawn the second time, assess how much fertilizer is left again.

Continue making adjustments and alternating fertilizer patterns until you are out of material.

Repeat this process for the front lawn.

Eventually you will get a feel for your spreader, and get to know your property.  The goal is to eventually learn your settings so that you only need to apply twice in a perpendicular pattern.

Lastly, don’t be afraid to break your lawn up into several sections, especially if you have natural or man made features that break up your lawn.  The smaller the better when trying to learn your spreader settings.

Check Out These Posts Next

NPK Meaning

Lawn Care Schedule Using Only 3 Products

Top Dressing Lawn: Advice and Benefits

Core Aeration and Overseeding

Lawn Dethatching: Everything You Need to Know

Lime Your Lawn: A Complete Guide

How to Do a Soil Test

How to Kill Weeds Without Killing Grass

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