The Basics of Fertilizing the Lawn- What is NPK?

What is NPK?

Look, we all know that fertilizer for the lawn is a crucial part of lawn care.

Just like your body, your lawn can not grow right without the proper nutrients.

Perhaps some of the most important nutrients for your lawn are NPK. But, what does that mean?

This guide to fertilizer for the lawn is aimed at giving you a basic understanding of what is in lawn fertilizer, most specifically, what is NPK?

There is a lot to cover, so lets get started!

What is NPK?

Simply put, when it comes to lawn fertilizer NPK stands for:

  • Nitrogen-(N
  • Phosphates- (P)
  • Potassium or Potash- (K)
  • or NPK

It’s true, that your lawn needs a lot more than NPK. We will get into that in other posts. However, to get started we will have to cover why NPK is such an important part of lawn fertilizer.

Reading the Numbers of NPK on Lawn Fertilizer

Have you ever seen a 3 part number like 10-10-0 or 3-2-1 on lawn fertilizer packaging?

Well, that stands for the amount of NPK or Nitrogen, Phosphate, and Potassium.

Yes, K stands for potassium. I know, it’s confusing.

Most specifically, these numbers stand for the percentage each nutrient makes up of the lawn fertilizer. So a 10-0-0 would be made of 10% Nitrogen. The rest of the number would be made up by inert fillers required to distribute the lawn fertilizer properly.

What is NPK lawn fertilizer?

What Does NPK Do for the Lawn?

Obviously, NPK is important for an awesome lawn.

In fact, NPK is everywhere, and it is an un-ignorable part of lawn fertilizer. But why is NPK so important when it comes to lawn fertilizer?

To explain why NPK is so important for the lawn, we need to look at each nutrient individually. This information is best represented by this table:

Table of NPK Nutrients

NutrientPurpose and effect on LawnBest Time to Apply
Nitrogen (N)
Needed for vegetation. Causes grass to be greener and grow thicker. Spring- Summer
Phosphate (P)Needed to build a healthy root system.Spring or Autumn
Potassium or Potash (K)Stimulates healthy growth and prevents diseaseSpring or Autumn

As you can see from the chart approve. Each part of NPK is critical for developing a healthy lawn.

However, there is much more to proper fertilizing of the lawn, than simply adding NPK lawn fertilizers to the lawn….

Test the Level of NPK in Your Soil

Whether you intend to use a commercial lawn fertilizer or an organic fertilizer for the lawn. Before applying any NPK lawn fertilizer, your should test your soil first.

Soil test kits are available at most local department stores and they can easily tell you the level of NPK in the lawn.

Using a soil test kit will prevent you from over fertilizing the lawn, and worst of all wasting money!

Once you have tested the level of NPK in the lawn already, you will have a better understanding about how much fertilizer for the lawn you will need, and what NPK mixture is best for your lawn.

There is More to Fertilizer for the Lawn than NPK

Get this, NPK is only the start of understanding how to fertilize your lawn.

In other posts we will look at:

  • Why pH is important for the lawn
  • What are humates for the lawn
  • and other topics about fertilizer for the lawn.

The Bottom Line

Everything needs proper nutrients to grow. Whether it is your body, your lawn or a tree, the right nutrients can make a huge difference!

Fertilizer for the lawn is a lot to understand, and understanding NPK is only the beginning. That is why fertilizing is best left to the professionals.

However if you are a lawn care professional yourself, or just a homeowner who loves their American lawn. You can count on us to help you understand your lawn and how t make it look its best.