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Understanding Fertilizer Numbers to Grow a Healthier Lawn

Understanding Fertilizer Numbers to Grow a Healthier Lawn

You know it’s time to fertilize your lawn, so you head to the store. As you walk through the fertilizer aisle, you notice three numbers on the front of each product. The first reads “23-3-8.” The second one is marked with “24-3-6.” Bags three and four also sport a series of three digits. You aren’t sure what these numbers mean or which seasonal blend your lawn needs to reach its maximum beauty.

Understanding these numbers, buying the right amount of fertilizer, and applying it properly throughout the year will empower you to grow the lawn of your dreams. To get started, here’s what you’ll need to know.

What Do Fertilizer Numbers Mean?

The numbers on the front of your lawn fertilizer bag are a “fertilizer grade”, sometimes called an “N-P-K ratio”, which describes how much Nitrogen, Phosphorus and Potassium it contains. These are three of the most important nutrients for your lawn, and different fertilizers will contain different balances of each.

As the seasons change, your lawn will need more of some nutrients than others to stay healthy and strong. This is why you see a different set of numbers on each of our IFA 4Plus seasonal fertilizers. Let’s look at these numbers more closely and see what they’re doing for your lawn.

See how and when to apply 23-3-8 Crabgrass Preventer + Lawn Food in early spring–step 1 in the annual IFA 4Plus Lawn Care Program

What Are N-P-K Ratios?

It’s important to note that the Nitrogen, Phosphorus, and Potassium numbers on your fertilizer are percentages. For instance, a bag labeled with “23-3-8” will contain 23% Nitrogen, 3% phosphorus, and 8% Potassium. Together, these percentages show the fertilizer’s “N-P-K ratio”. So, what does each nutrient do for your lawn?

nitrogen is the first fertilizer number

Nitrogen and Its Role in Fertilizer

The first number listed represents the percentage of nitrogen in the bag

Nitrogen helps your grass to appear green, lush and thick. Nitrogen aids in the creation of chlorophyll, which is responsible for producing the green pigment in the grass and is the compound by which plants use sunlight to produce sugars from carbon dioxide and water.

Nitrogen or “N” stimulates new root growth. Many early spring fertilizers will have a higher Nitrogen level to give the lawn a kick and get it growing early. It can help turf recover from environmental stresses and injury. An application of nitrogen in the spring, and then timely spreading throughout the growing season will help fortify turf to better withstand environmental stresses such as heat and insects.

phosphorus is the second fertilizer number

The Benefits of Phosphorus in Fertilizer

The second number represents the percentage of phosphorus

Phosphorus is critical in developing and strengthening a healthy root system of turfgrass. If only nitrogen is applied to the lawn, the grass will be nice and green, but as watering or a drought hits the grass will be greatly impacted. Having strong roots in your grass will keep your lawn healthy through the changing weather and stresses of the seasons.

Phosphorus or “P” is a primary plant nutrient that is involved in the metabolic processes responsible for transferring energy throughout the plant. It’s crucial to introduce phosphorus when first establishing turfgrass and continue application as the grass grows. An abundance of phosphorus allows plants to grow more efficiently.

potassium is the third fertilizer number

The Perks of Potassium in Fertilizer

The final number is the percentage of potassium

Potassium is important to overall plant health. Potassium or “K” supports the internal process of the plant cells that affects photosynthesis, water absorption, respiration and protein production. A deficiency of potassium weakens a plant and increases its vulnerability to drought, temperature fluctuation injury and disease.

Adding soluble potash (K2O) to the soil helps grass withstand stress, drought, and disease. Specifically, potassium helps maintain pressure in the cells of the plant, resulting in a positive influence on drought tolerance, cold hardiness, and disease resistance.

4plus lawn care program

Achieve the Beautiful Lawn You Desire

The N-P-K ratio in each bag of fertilizer varies from season to season. It changes based on the nutrient requirements of turfgrass for the upcoming weather and temperatures expected for the next 6-12 weeks. In the IFA 4Plus annual lawn care program, steps 1 and 2 establish a foundation for a healthy, weed-free lawn. Then, steps 3 and 4 provide your lawn with a perfect balance of nutrients according to the season.

Fertilizing in Spring and Summer

You’ll notice the fertilizer numbers “25-5-10” on our IFA Spring & Summer fertilizer. A slow release of nitrogen delivers even, consistent feeding throughout hot summer months. Plus, with slightly more Potassium than the previous steps, you’re supporting the lawn’s ability to absorb water, produce proteins, and stay healthy.

Fertilizing in Fall and Winter

Up next, our IFA Fall & Winter fertilizer loses some Nitrogen content, and gains Potassium with fertilizer numbers that show “22-2-12”. This fertilizer helps to continue nourishing your lawn through the milder fall months and boosts its ability to stay strong and healthy during winter months.

IFA 4Plus Lawn Care Fertilizer Program

The IFA 4Plus Lawn Care program is locally formulated and specifically designed to help produce the best results in the Intermountain West. With two of our four applications, we also use Omnicote Technology that allows micronutrients such as Zinc, Iron, and Manganese to coat every pellet of fertilizer and thus getting an even nutrient distribution on the lawn. These elements may not require the quantity of the three major elements, but they are just as important.

Learn more about the products in IFA's 4Plus Lawn Care Program

When applied in conjunction with each other, IFA 4Plus Lawn Care maintains the rich, deep green lawn you desire each season, while also building stronger, healthier turf for future years.

Let Us Help

As always, let the good folks at IFA Country Store help answer questions when you’re walking through the fertilizer aisle on your next visit. The success and beauty of your lawn is important to us.


Information for this article was provided by Brad Schumann, Branch Manager, Logan IFA Country Store; Bret Yardley, Branch Manager, Richfield IFA Country Store; and Ken Holt, Lawn & Garden Category Manager, IFA Country Store.