When to Fertilize a Lawn

Fertilizing your lawn at the right time is crucial for getting a thick, green, and healthy lawn. Proper fertilization encourages deep root growth, increases drought tolerance, and gives your grass the nutrients it needs to crowd out weeds. Follow this guide to know exactly when to feed your lawn.

Why Fertilize Your Lawn

Fertilizing provides essential nutrients, mainly nitrogen, that grass plants need to thrive. Nitrogen promotes lush, green growth and allows the grass to recover quickly from wear and tear. Other nutrients like potassium and phosphorus contribute to root development, disease resistance, and hardness.

Fertilizing at the right times encourages your lawn to develop deep, extensive root systems. Deep roots make the turf more heat and drought tolerant. Fertilizing also gives your desired grass species a competitive edge over weeds. A dense, vigorous lawn leaves little room for weeds to establish.

Best Time to Fertilize Cool-Season Grasses

Cool-season grasses like bluegrass, fescue, and ryegrass grow best in spring and fall. Focus fertilizer applications during these periods:

Early Fall

The best time to fertilize cool-season lawns is early fall, around Labor Day. Fall fertilizing fuels root growth going into winter. Longer days and cooler nights in September are ideal for root development. Aim to get fertilizer down at least 6 weeks before the average first frost in your area.

Apply 1 lb of nitrogen per 1,000 square feet. Fast-release synthetic fertilizers work well in fall. The cooler weather minimizes burn risks.

Early Spring

The second best time to fertilize cool-season lawns is early spring, when soil temperatures reach 55°F. This is usually early April but can vary by region. Spring feeding supports quick green-up and recovery after winter.

Use a balanced slow-release fertilizer in spring. This prevents rapid growth that could leave grass susceptible to disease. Apply 0.5-1 lb of nitrogen per 1,000 square feet.

Early Summer

An early summer application in early to mid-June can also benefit cool-season lawns. Fertilize at half the rate you would in fall. This provides nutrients for continued fill-in and thickness.

Avoid late summer fertilizing of cool-season grasses. High temperatures increase disease risk with excess nitrogen.

Best Time to Fertilize Warm-Season Grasses

Warm-season grasses like bermudagrass, zoysia, and St. Augustine thrive in summer. Time fertilizer applications as follows:

Late Spring

Fertilize warm-season grasses when they green-up and resume growth in late spring. This is usually late May but depends on your climate. Use a balanced slow-release fertilizer to provide steady nutrients through summer. Apply at a rate of 1 lb of nitrogen per 1,000 square feet.

Early Summer

Apply a second round of fertilizer in early to mid-June. Fertilizing at this time enhances summer growth and color. Use 1 lb of nitrogen per 1,000 square feet. Consider a fast-release fertilizer, since warm weather minimizes burn risks.

Late Summer

Apply a final fertilizer application in late August to early September. This nourishes the grass for fall growth and prepares it for winter dormancy. Use a slow-release product and reduce your nitrogen rate to 0.5 lbs per 1,000 square feet.

Avoid fertilizing warm-season grasses in spring and fall. Cooler temperatures limit nutrient uptake during these periods.

Other Tips for Proper Lawn Fertilization

Follow these additional tips for the greatest benefits from fertilizing:

  • Always follow application guidelines on the fertilizer bag based on grass type.
  • Time applications for periods of moderate temperatures and expected rainfall or irrigation.
  • Use a spreader for even coverage and reduce risks of burn spots.
  • Consider a soil test every 2-3 years to know exactly which nutrients your lawn needs.
  • Let clippings decompose after mowing to return free nutrients to the soil.
  • Fertilize at least 1-2 weeks before or after using weed control products.

Proper timing is critical for fertilizer effectiveness. Adjust your schedule based on weather and lawn conditions each year. A little planning goes a long way to building a healthy, thriving lawn.

Frequently Asked Questions About When to Fertilize a Lawn

When should I fertilize my lawn in spring?

For cool-season grasses, fertilize in early spring when soil temperatures reach 55°F. This is usually early April but varies by region. Fertilize warm-season grasses in late spring when they green-up, usually late May.

When should I fertilize my lawn in summer?

Apply a summer feeding to cool-season grasses in early to mid-June at half the normal rate. Warm-season grasses should be fertilized in early and late summer for enhanced growth. Avoid late summer fertilizer on cool-season lawns.

When should I fertilize my lawn in fall?

Fall is the most important time to fertilize cool-season grasses. Apply fertilizer around Labor Day when temperatures cool but grass is still actively growing. Warm-season grasses should receive a final fertilizer application in late summer to early fall before going dormant.

Should I fertilize before or after mowing?

It’s best to fertilize lawns 1-2 days after mowing. This allows the blades of grass access to the nutrients. Before mowing can cause fertilizer to get washed off by clippings.

How often should lawn fertilizer be applied?

Cool-season lawns benefit from two fertilizer applications per year, in fall and spring. Warm-season grasses do well with three yearly applications, in late spring, early summer, and late summer.


Properly timing lawn fertilization encourages deep rooting, green growth, and overall vigor in grass plants. Cool-season grasses thrive when fertilized in fall and spring. Warm-season varieties benefit from late spring, early summer, and late summer feedings. Adjust your fertilizer schedule annually based on weather and lawn health. Providing your lawn the right nutrients at the right times leads to a lush, thick, and beautiful turf.