Fall Lawn Fertilizer: Your Guide to a Healthier Spring Lawn

While many see fall as the end of the lawn care season, it’s actually the most important time to prepare for the year ahead. As temperatures cool, your lawn's energy shifts from producing green blades to developing deep roots and storing nutrients.

A well-timed fall lawn fertilizer application supports this critical natural process. It builds the foundation for winter survival and a strong spring return by:

• Strengthening grass from the roots up
• Improving resilience against cold and disease
• Storing energy for a vibrant, healthy lawn next spring

Choosing the right fall lawn fertilizer

To support your lawn's shift towards root growth and energy storage, the best fall fertilizer will focus on nitrogen and iron, often supplemented with beneficial ingredients like seaweed or micronutrients. These key inputs work together to nourish the plant below the surface without encouraging unnecessary top growth before winter.

• Nitrogen is the most critical nutrient. It fuels root development and helps the grass store carbohydrates (energy) for dormancy.
• Iron helps maintain green color and supports overall plant health as temperatures drop.
• Seaweed contains compounds that enhance root growth and improve the lawn's resilience against winter stress.

What to avoid in fall lawn fertilizers

Just as important as providing the right nutrients is avoiding those that can disrupt your lawn's preparation for dormancy. Many traditional "winterizer" fertilizers contain high levels of potassium (K) or phosphorus (P).

Excess potassium in late fall can encourage certain winter diseases like snow mold, while most established lawns already have enough phosphorus in the soil. Adding more is unnecessary and doesn't support the primary goal of building energy reserves. Plus, your lawn is already getting an influx of phosphorus in the fall from falling leaves.

Look for a fall lawn fertilizer with an N-P-K ratio like 22−0−0 (no P or K), with key ingredients like nitrogen, iron, seaweed, and micronutrients.

Fall Fortify Plus Micronutrients Lawn Fertilizer

Our 22−0−0 NPK fall lawn fertilizer is designed to support fall's unique needs. It extends green color and strengthens grass without pesticides.

When to apply fall lawn fertilizer

Timing is key to getting the most from your fall fertilizer. Apply it while the grass is still green and actively absorbing nutrients, but after the high growth of summer has slowed. For most regions, this is between August and October.

• Warm-season grasses: Apply from mid-August to late September
• Cool-season grasses: Apply from late August to mid-October

Sunday Tip:

If you're in Florida or other year-round warm climates, you can apply fall fertilizer until November!

Do you already have a Sunday custom plan?

Your Sunday custom lawn plan offers the best application times tailored to your lawn's specific location. You can visit the My Plan section in your account to find your customized schedule.

Fall lawn care tips for a healthier spring

Fertilizing is the cornerstone of fall lawn prep, but a few other fall lawn care tasks will complete the foundation for a healthy spring.

• Patch and overseed: Cooler air temperatures and warm soil create the perfect window to repair bare spots and overseed for a thicker, more resilient lawn.
• Adjust watering and mowing: As top growth naturally slows, you can reduce watering frequency. You can also raise your mower blade for the final cuts of the season to help insulate the grass crown from the cold.
• Manage weeds: Many weeds are most vulnerable to spot treatments in the fall as they transport energy down to their roots. Making fall a highly effective time for weed control.
• Rake leaves: Remember to rake or mulch fallen leaves regularly. A thick layer of leaves can trap moisture and smother the grass you've worked hard to prep for winter.

Cited sources

Fertilizing Cool Season Lawns. Kansas State University Extension

Rethinking Fall Fertilization. University of Nebraska-Lincoln Extension