You don’t want to buy too little, or worse, apply too much and damage your lawn!

In my our last blog post, I explained what the numbers on the bags of fertilizer mean (last blog post). With that information, you can determine how much of a specific fertilizer to buy and apply on your turf.

“Fertilizer Rate” is defined as: “pounds of nitrogen per 1,000 sq ft of turf”. In the lawn care industry, the general rule of thumb is to shoot for a fertilizer rate of between 0.5 lbs and 1.0 lbs of nitrogen per 1,000 square feet of turf.

  • More than 1.0 lbs N / 1,000 sq ft will likely damage your turf.
  • Less than 0.5 lbs N / 1,000 sq ft usually doesn’t produce results worth the effort.
  • 0.5 lbs N / 1,000 sq ft will noticeably green up your lawn.
  • 1.0 lbs N / 1,000 sq ft will make it the greenest lawn on the block and require frequent mowing.

Choosing a fertilizer rate within the range above is personal preference. We’re going to stick with 0.5 lb N / 1,000 sq ft for this post.

4 Steps to determine how much fertilizer you need:

  1. Measure your Turf Area in square feet
    • Break your lawn up into rectangular sections and add them up.
    • Sneaky Tip: Get us to professionally measure your lawn for you: request a free quote at ProLawnsMN.com/contact (West Metro lawns only). Before the end of the next business day you’ll have your measurement – no obligation.
  2. Get first number off your bag of fertilizer. This is the % Nitrogen.
  3. Decide the Fertilizer Rate you want. I recommend 0.5 lb N / 1,000 sq ft.
  4. Calculate the Fertilizer Amount you should be putting down.
    • [Fertilizer Amount] = {{[Turf Area] / 1000} x [Fertilizer Rate]} / {[% Nitrogen] / 100}
    • This equation can be simplified to:

[Fertilizer Amount] = ([Turf Area] x [Fertilizer Rate] x 0.1) / [% Nitrogen]

Example) Your lawn has 8,720 sq ft of turf and you want to apply a “24-0-12” fertilizer at a rate of 0.5 lb N / 1,000 sq ft. Plugging the numbers into the equation would look like:
    1. [Fertilizer Amount] = ([Turf Area] x [Fertilizer Rate] x 0.1) / [% Nitrogen]
    2. [Fertilizer Amount] = (8720 x 0.5 x 0.1) / 24
    3. [Fertilizer Amount] = (436) / 24
    4. [Fertilizer Amount] = 18.167

So the amount of “24-0-12” you want to apply to your lawn is about 18 lbs or less than half of a 50 lb bag. Buying one bag would do two applications on your lawn.

These “if I didn’t work at” posts are intended to show the DIYer how to get professional results on their lawn. Stay tuned for more.