How to Apply Lawn Fertilizer

Lawn fertilizer being spread across lawn

The Spruce / Adelyn Duchala

Project Overview
  • Working Time: 2 - 3 hrs
  • Total Time: 2 - 3 hrs
  • Skill Level: Beginner
  • Estimated Cost: $60

When your grass is not looking up to par, your first instinct may be to apply some fertilizer to the lawn. While not necessarily an incorrect instinct, it is important to realize that the devil is in the details. You must consider exactly how to apply fertilizer to your lawn, including the right time to do so. Failure to take such considerations into account can result in wasted fertilizer or, worse yet, a burned lawn.

Learn about all the steps required to fertilize your lawn the right way, making it the envy of the neighborhood.

Time of Year to Apply Fertilizer

The correct time for you to be applying lawn fertilizer can depend, in part, on the type of grass you grow. People in the northern United States generally grow cool-season grasses, while those living in the South generally grow warm-season grasses. For both types, growers often apply lawn fertilizers in late spring and in late summer. But for cool-season grasses, a third application is often made in late fall.

Your most important feeding for a cool-season grass may well be the one in late fall. This "winterizing" feeding does more than just prepare your lawn for winter: The nutrients supplied will get the lawn off to a good start the next year, in early spring.

Before Getting Started

Buy the lawn fertilizer ahead of time and have it on hand so that you're ready to go when the weather cooperates and when there's time in your schedule for you to do it.

Consult the weather forecast before starting. Avoid applying lawn fertilizer when heavy rains are in the forecast, as these would wash the fertilizer away. But if a steady, moderate (1/4 inch or so) rain is expected overnight or the next day, this is an ideal time to fertilize.

Roughly measure the square footage of your lawn. Fortunately, making the calculation is just a one-time task (unless you expand your lawn area). Write the figure down for future applications. You need neither fancy tools nor a mathematical mind to figure out the square footage of your lawn, even if it is an irregularly-shaped space:

Divide your lawn into predetermined rectangular sections. To do this, decide in advance on the section size you'll be comfortable working with, then measure out a section with the tape measure and mark it off with spray paint. For example, you could measure out a 10x5 rectangle in one corner of your lawn. Mark the lines with spray paint as you go so that you'll know where you left off. Repeat on the next portion of your lawn and so on, until you've accounted for the whole lawn. It doesn't have to be exact.

Finally, go back and add up all those 10x5 rectangles. Each one is 50 square feet. So if you have twenty of them, that's 1000 square feet of lawn. You'll need this figure when it's time to determine the amount of fertilizer needed for the job.

What You'll Need

Equipment / Tools

  • Spreader
  • Tape measure
  • Can of orange spray paint


  • Bag(s) of lawn fertilizer


Regardless of the time of year you are applying lawn fertilizer, and regardless of whether you are applying it onto a cool-season or a warm-season grass, the application process is the same.

Materials and tools to fertilize a lawn

The Spruce / Adelyn Duchala

  1. Choose a Spot to Fill Your Spreader

    Don't fill your spreader on the lawn. If you were to spill some on the lawn, you could burn it. Instead, wheel the spreader onto your driveway or another hard surface and fill it there.

    Spreader with wheels propped on cement road to add fertilizer

    The Spruce / Adelyn Duchala

  2. Read Instructions on Bag

    Check the fertilizer bag for application instructions. Somewhere it will indicate the setting to use on your spreader and how much fertilizer to apply across 1000 square feet (keep in mind that fertilizer applied in excess can burn a lawn).

    Instructions pointed out on back of lawn fertilizer bag

    The Spruce / Adelyn Duchala

  3. Check Setting on Spreader

    If your spreader setting does not already match that indicated in the instructions, adjust it to that setting.

    Spreader setting adjusted by turning white knob

    The Spruce / Adelyn Duchala

  4. Fill Your Spreader

    Here's where you need the square-footage measurement you took of your lawn. So if the instructions call for x amount of fertilizer for 1000 square feet, and your lawn measures only 500 square feet, you would fill your spreader with 1/2 the amount of x. If your lawn has 2000 square feet, you'll double the amount.

    Lawn fertilizer added to spreader container

    The Spruce / Adelyn Duchala

  5. Apply Fertilizer to Perimeter

    Apply the fertilizer to the edges of your lawn first, walking at an even pace.

    Lawn spreader applying fertilizer to perimeter of grass

    The Spruce / Adelyn Duchala

  6. Finish Applying Fertilizer

    Turn off the spreader when you have covered the edges to avoid uneven application as you reposition the spreader to apply fertilizer to the interior. After turning the spreader back on, begin applying fertilizer to the rest of the lawn. Still walking at an even pace, move back and forth between the perimeter. As you go, check on coverage; if there are gaps, try making overlapping passes.

    Lawn spreader rolling across lawn adding fertilizer

    The Spruce / Adelyn Duchala

  7. Water in the Fertilizer

    It's ideal if nature follows up your application with a steady, moderate rainfall because the rain provides even coverage across the lawn in a way that a sprinkler system is hard-pressed to do. However, if nature doesn't cooperate, water the fertilizer in yourself.

    Lawn being watered with garden hose after fertilizing

    The Spruce / Adelyn Duchala