Why Fertilize the Lawn?

The soil supplies turfgrass with some essential nutrients, but most soils can't provide everything your lawn needs throughout the whole growing season. An actively growing lawn uses a great deal of energy from these nutrients. Lawn fertilizer helps your grass stay healthy by:

Promoting new leaf and root growth
Aiding in recovery from foot traffic and pest damage
Reducing and controlling weeds
Replacing nutrients lost to leaching, volatilization and grass clipping removal

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Choosing Lawn Fertilizer

Choose the right food for your soil to achieve the healthiest, greenest lawn. The best fertilizer for your grass depends on a number of factors. You'll want to consider where you live, what type of grass you have and what season it is when choosing the right type of lawn fertilizer. Our Fertilizer Buying Guide can help you make the correct choice.

When Should You Fertilize Your Lawn?

For the best lawn care, you need to feed your grass at the right time. Different types of grass need fertilizer at different times. We've provided general guidelines below, but for specific details for regions and grass types, see our tips for scheduling your fertilizer program.

In general, you should fertilize while your lawn is actively growing. It takes some commitment, but a regular fertilizing schedule will give you a great-looking lawn year after year.

Fertilizing Cool-Season Grasses

The growing season for cool-season grasses is mainly in the cool months of spring and fall when the temperature is in the range of 60 to 70 degrees Fahrenheit. These grasses grow most vigorously in the fall. Fertilize heavily in the fall — when the intense heat of summer has subsided but well before the onset of severe cold weather. You may choose to apply a winterizer fertilizer for the fall application. These fertilizers are formulated to help protect the grass during the winter months.

Fertilize lightly in early spring with either slow-release or quick-release fertilizer. Time your fertilization schedule to use up all the fertilizer before the onset of hot summer weather, when cool-season grasses often go dormant.

Fertilizing Warm-Season Grasses

Fertilize when the grass starts to turn green in spring. The growing season for these grasses is late spring and early summer, depending on your geographic area. Warm-season grasses grow best when the temperature is between 80 to 95 degrees Fahrenheit, although they'll often grow outside of this range.

Use either slow- or quick-release fertilizer and time your feeding schedule so that it'll be used up before the onset of severe hot summer weather. Fertilize again after the intense heat has subsided.

Tip

To prevent damage to your lawn, time your feedings so that no fertilizer is present at the onset of severe hot or cold temperatures.

Preparing the Lawn for Fertilizing

Before you begin fertilizing, there's some prep work you need to do to make sure the fertilizer will be as effective as possible.

Before You Fertilize a Lawn

Map of United States showing grass types.

The best lawn fertilizer for a thriving lawn depends on the kind of grass you have. Southern zones have warm-season grasses, while northern zones have cool-season grasses. The area in between is known as the transitional region. If you live there, you'll see both warm- and cool-season grasses. You can distinguish between the two because warm-season grasses turn brown after the first frost, while cool-season grasses generally stay green all year. Cool-season grasses won't survive summer in the warm-season zone.

Your soil's pH level — the amount of alkalinity or acidity it contains — determines how the grass will use the ingredients in the fertilizer. There are different types of fertilizers, so use a home testing kit to help determine which fertilizer numbers are best for your grass. Your county extension office may offer analysis services as well. Bring your soil as close to neutral as possible to get the most benefit from the fertilizer you use. A pH range between 6.0 and 7.0 is considered ideal for growing quality grass.

Fertilizers, weed killers and other soil amendments are typically sold by the amount necessary to cover a certain square footage. Determine the size of the area you want to fertilize by multiplying the length of your lawn by its width. Then subtract the square footage of the house, driveway and other areas you won't be fertilizing.

An example using rough measurements:

Lawn: 250 x 150 ft = 37,500 sq ft

House: 80 x 36 ft = 2,880 sq ft

Driveway: 12 x 50 ft = 600 sq ft

Total = 34,020 sq ft

Fertilizer is usually sold in bags that cover 5,000 or 15,000 square feet, although other sizes are available. In the example above, 34,020 divided by 5,000 square feet per bag equals 6.8. That means you'll need either seven 5,000-square-foot bags or two 15,000-square-foot bags and one 5,000-square-foot bag.

Tip

If you're applying granular fertilizer, it's a good idea to water your lawn several days before application.

Easy Steps for Proper Fertilizer Application

We have general steps for fertilizing your lawn with dry granules or a liquid fertilizer, but when using any lawn-care products, follow the fertilizer manufacturer's instructions for application and safety.

Broadcasting Fertilizer Granules

Spraying Liquid Fertilizer

If the liquid fertilizer comes in its own hose-end sprayer bottle, simply attach it to the hose.

If the fertilizer requires a separate sprayer, fill the sprayer canister with liquid fertilizer according to the package instructions. For hose-end sprayers, carefully attach the canister unit to the end of your garden hose. For handheld sprayers, prepare them to apply the liquid, typically by pumping a handle to build pressure.

Caution

Be sure to keep any fertilizer away from your eyes, mouth and skin. Use safety gear, such as appropriate eye protection, respiratory protection and gloves, as recommended by the manufacturer. Wear long pants, a long-sleeved shirt and rubber boots. Keep people and pets off the grass for the time period indicated in the instructions. For maximum efficiency and safety, don't apply fertilizer on windy days. Follow any instructions regarding how long to wait before allowing people or pets back onto the lawn.

Fertilizer Spreaders

Broadcast spreaders (also called rotary spreaders) drop fertilizer from a hopper onto a spinning disc that disperses it over the lawn. Drop spreaders cover straight lines with little waste, but they must be used with care to avoid creating stripes.

Tip

Check the label on the fertilizer bag for specific settings, which will vary by product and spreader model.

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How to Fertilize Your Lawn