When and How to Fertilize Your Lawn in the Spring

Man pushes broadcast spreader across lawn as it distributes fertilizer.

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Winter has come and gone and the sun is finally shining. That can only mean one thing. It’s time to show a little love to your lawn. But how do you know exactly when to fertilize in the spring? It comes down to science — and practice. Don’t worry! All you need to do is follow some simple steps.

Start with the Soil

A healthy, green lawn always starts with what’s going on below it. Use a soil thermometer to check the ground temperature. When it hits 55º F under the surface, it’s officially time to fertilize. This typically happens in early spring, around mid- to late-April. Or, just look for growing grass or blooming lilacs. That’s always a sure sign it’s go time.

After your first round of fertilizer, feed your lawn again about four weeks out — right around mid-May. By that time, you’ll be a pro. This is good because you’ll want to fertilize your lawn every six or eight weeks throughout the active growing season — which lasts through October.

Now that you know when to fertilize in spring, how do you?

Learn the ABCs of NPK

Every yard needs 16 essential elements for healthy growth. Most come from its environment, but three elements, Nitrogen (N), Phosphorus (P), and Potassium (K), are needed in larger quantities. This is why you need to fertilize to sustain a healthy yard. So, what do they do?

Two hands holding white seed in one hand and black nitrogen seed in other

Nitrogen (N)

That deep green color you love? That’s the work of Nitrogen. Beyond the beauty it brings, it also adds proteins and enzymes to add the sturdy growth and shoot density needed to beat weeds, diseases and insects.

Phosphorus (P)

Phosphorus stays in the soil to aid root growth and improve establishment rates.

Potassium (K)

Potassium often leaches into the soil and enhances grass resistance to cold, disease, drought and wear.

Test it Out

Levels of these three naturally occurring elements often vary pending where you live. To make sure you’re fertilizing your lawn correctly based on its unique needs, do a soil test. It will tell you the appropriate fertilizer mix for your lawn.

Bag it Up

10-10-10 Fertilizer bag 40lb bag

Fertilizer is a numbers game. Literally. Each bag of fertilizer has a set of numbers on it that are important to understand. These numbers refer to the amount of N, P, and K that’s in it. For example, if you see 20-10-10, that means it has 20% N, 10% P, and 10% K. Look at your soil test results to see which bag is best for your grass type. You probably can’t go wrong with a basic 20-5-10 lawn fertilizer mix in spring.

Starting from grass seed? If your state allows it, choose a fertilizer that contains phosphorus to help the root system develop. An 18-24-12 lawn fertilizer is a good place to start.

Hose it Down

If you feed your grass, it needs a drink. But remember, the more you water your lawn, the more fertilizer it will need. This is because as the grass grows, it uses more nutrients. Fertilizer helps replace those nutrients. Yards that have automatic sprinklers can go about six weeks between feedings. If you water by hand, you can wait two more weeks. Check your fertilizer bag to see if you should water your yard before or after applying fertilizer.

Go Slow

A slow-release fertilizer often has its advantages over fast-release fertilizer. For starters, slow-release releases its nutrients over time. This means you can wait a little longer between applications, typically around six to eight weeks. Opt for a slow-release fertilizer that has nitrogen to keep your lawn looking green. Aim for two to three pounds of nitrogen throughout the whole growing season.

Now That You Have the Knowledge, Apply Yourself

Fill up a handheld or pushcart lawn spreader with fertilizer granules and get busy. Apply the fertilizer around the perimeter and then work your way in. Criss-cross your yard to assure adequate coverage and prevent over coverage. Remember, less is more. You don’t want to waste money, or worse, burn your yard by over fertilizing. You’ve seen those yards. You’re better than that. Sweep up excess fertilizer granules to keep Mother Nature happy. With a little practice, you can get your lawn fertilized and looking green and healthy in no time. When you’re ready to cut it, Toro has plenty of lawn care tools for that, too.