What Does NPK Mean on a Fertilizer Label? NPK Ratio Explained.

When I first got into lawn care and landscaping, one of the most dizzying things to get a grasp of was the NPK numbers and what each is referring to along with the benefit of each of the letters. Below I’ll try to breakdown the mystery of what NPK stands for in fertilizers.

Fertilizers come with 3 numbers on them.

  • The first number shows the ratio of nitrogen in the fertilizer
  • The second number represents the ratio of phosphorus.
  • The third number is the ratio of potassium

The formulation is, therefore, an N-P-K fertilizer, whether it is a liquid concentrate or even a granular feed.

Some fertilizers may contain other elements such as humic acid, fluvic acid, iron, etc. These give additional benefits. More on these below.

N is for Nitrogen

nitrogen benefits

It is a macro-nutrient that is key for feeding lawns. Almost all grass types rely heavily on nitrogen for their development. Nitrogen is important for the following purposes:

  • Shoot development
  • Root development
  • Color of the lawn
  • Recuperative ability of the lawn
  • Growth rate and density

P is for Phosphorus

Phosphorus benefits

Phosphorus is also an important major nutrient in any of the best fertilizers for Bermuda grass lawns.

It is important for the general well-being of the lawn, especially when starting out. In a starter fertilizer, phosphorus will help with faster root development as well as general growth rate.

Most yards already have adequate phosphorus. However, you may still need to put down a good starter fertilizer for Bermuda grass to help it develop deeper roots and out-compete weeds in the absorption of nutrients.

To determine how much phosphorus to put down in your lawn, take a soil sample and send it to the soil testing laboratory first. You’ll be advised on how much of this nutrient to apply, which will also help you choose a good fertilizer for your Bermuda lawn.

K is for Potassium

Potassium benefits

Potassium has some great benefits and it is very important to look at this number when shopping for the best fertilizer for Bermuda grass lawns.

You need to put down some potassium to help your lawn become more drought-tolerant especially in the summer days.

While there are some varieties of Bermuda grass that do well than others in the summer, you’ll want to get a fertilizer that has some amounts of this nutrient in them.

Potassium in lawn fertilizers has the following benefits:

  • Helps with cell growth and development
  • Drought resistance
  • Improves rooting

Now that you know the role of those 3 letters on your fertilizer, you’re right to think that the top-rated products we reviewed would be best for your needs. The first place to start should always be soil testing to get your pH level.

If your soil returns a high phosphorus level then you will want a fertilizer with a low to 0 rating for the P. ie. 12-0-5

I have reviewed lots of fertilizer with various NPK rations for all types of grasses and have broke them down here: