How to Calculate Fertilizer for the Yard


Feeding your lawn with the right material is one of the best things you can do to help it grow properly. But how do you know how much fertilizer to apply? Whether you have a small lawn or sprawling acres, there's a method to calculating the correct amount of fertilizer.

Step 1

Take measurements with a measuring wheel to determine the amount of square feet a lawn has. Multiply the length and width, in feet, for square and rectangular lawns. Multiply the base by one-half for triangular-shaped lawns. Take the radius, square it and multiply it by pi (3.14) for circular lawns. Exclude walkways or any other area not covered by grass when measuring.

Step 2

Find out how much nitrogen is in your fertilizer. Look at the series of numbers, a three-number code, on the front of the fertilizer's bag. The first number tells how much nitrogen. Follow the manufacturer's guidelines to determine how much fertilizer will be needed to deliver the appropriate amount of nitrogen per 1,000 square feet.

Step 3

Multiply the square feet of your lawn by the amount of fertilizer needed to deliver the right amount of nitrogen. Refer to the manufacturer's recommendations to convert the number of pounds of fertilizer that should be applied to the total square feet to determine how many pounds of fertilizer to apply.

Things You'll Need

  • Measuring wheel


  • Calculating the Amount of Fertilizer Needed for Your Lawn
Keywords: feeding your lawn, nitrogen, how much fertilizer

About this Author

Stephanie Green is a writer with more than 10 years of experience. Her work has been published in various lifestyle and trade publications, covering parenting, gardening and human-interest stories. Green holds a Bachelor of Arts in English.