Fall is the most important season to fertilize your lawn, especially for cool-season grasses. While growth above ground slows, roots are busy storing nutrients for winter. The right fall fertilizer strengthens roots, builds resilience, and ensures a greener, healthier lawn come spring. In this guide, you'll learn exactly how to do it right.
While spring often receives the most recognition, it’s the careful groundwork done in fall that lays the foundation for a healthy lawn. Applying fertilizer in fall ensures your lawn gets the nutrients it needs to:
Choosing the right fertilizer depends on your grass type. Cool-season grasses (like fescue, bluegrass, and ryegrass) and warm-season grasses (like Bermuda, zoysia, and St. Augustine) have different nutrient needs in the fall.
Nitrogen is essential for fall root growth and nutrient storage. For cool-season lawns, a nitrogen-heavy fertilizer is ideal in the fall. Choose a product with an N-P-K ratio like 24-0-10 or 20-8-8.
Why it matters: Nitrogen boosts chlorophyll production, helping the lawn stay green and store energy for spring. Avoid excessive nitrogen late in fall, as it can stimulate blade growth that is vulnerable to frost damage.
Opt for slow-release nitrogen to ensure your grass receives nutrients gradually over several weeks. These products reduce the risk of fertilizer burn and provide consistent feeding as temperatures drop.
Examples: Milorganite, Scotts Turf Builder WinterGuard Fall Lawn Food
Phosphorus promotes root growth but most established lawns already have enough. Apply phosphorus only if a soil test shows a deficiency. Excess phosphorus can lead to runoff issues.
Best practice: Do a soil test every 2–3 years to guide phosphorus applications.
Potassium helps with cold tolerance, disease resistance, and overall hardiness. A fertilizer with adequate potassium, like 24-0-10 or 32-0-10, prepares your lawn to survive freezing temperatures and recover faster in spring.
Tip: Choose a fertilizer with a slow-release formula to ensure nutrients last through late fall.
Warm-season grasses are heavy feeders, especially when actively growing during spring and summer. The key nutrient for these grasses is also nitrogen, which promotes lush, green growth and robust root development. Look for a balanced fertilizer with a high nitrogen content, typically with an N-P-K ratio like 30-0-10 or 24-2-12.
Why it matters: Nitrogen helps grass grow vigorously and withstand heat stress. However, be cautious about applying too much nitrogen too late in the growing season, as it can cause excessive top growth that may not survive colder temperatures.
Similar to cool-season grasses, slow-release nitrogen fertilizers are best for warm-season grasses as they provide a consistent nutrient supply over time. Slow-release formulas release nutrients gradually, preventing the lawn from getting overwhelmed by too much fertilizer at once.
Examples: Scotts Turf Builder SummerGuard, Milorganite Organic Lawn Food
Potassium is vital for improving drought resistance, heat tolerance, and overall hardiness in warm-season grasses. It strengthens the plant’s cell walls, making it more resilient to stress from high temperatures and dry conditions.
Recommended Ratio: Fertilizers with potassium-rich formulations such as 18-0-20 or 16-4-8, are perfect during the peak growing months of summer, helping the grass withstand harsh conditions.
Phosphorus (the middle number in the N-P-K ratio) is not typically needed in large amounts for established warm-season lawns unless soil tests show a deficiency. Too much phosphorus can negatively affect the soil and nearby water bodies, so always test your soil before applying phosphorus-rich fertilizers.
Tip: Most established lawns have sufficient phosphorus unless a soil test indicates otherwise.
Organic Fertilizers (e.g., Milorganite or Espoma Organic Lawn Food) release nutrients gradually and improve soil health. They are great for long-term lawn health but tend to be less immediate in effect.
Synthetic Fertilizers (e.g., Scotts or Pennington) provide quicker, more predictable results. They’re ideal for feeding your lawn during its active growing season but should be used carefully to avoid nutrient overload.
Tip: Apply the last round of fertilizer for warm-season grasses 6-8 weeks before the first frost to allow absorption before dormancy.
Follow this step-by-step guide to maximize your fall fertilization efforts and set your lawn up for success.
Not all fertilizers work the same way in fall. Look for one with:
If your soil is deficient in specific nutrients, consider a soil test before fertilizing. Many lawn care experts recommend testing every 2-3 years to ensure you're giving your grass exactly what it needs.
Applying too early or too late can reduce effectiveness. Follow this ideal timeline:
First application: Early fall (late August – September) for root strengthening
Second application: Late fall (October – November) for winter resilience
Tip: Apply before the first frost but after summer heat subsides. If you live in a colder climate, aim to fertilize at least 3-4 weeks before the ground freezes to allow the nutrients to be absorbed properly.
Prepping your lawn ensures the fertilizer is absorbed properly:
Uneven application leads to patchy growth and nutrient deficiencies. Use:
Pro Tip: Overlapping passes by 50% prevents striping and ensures full lawn coverage.
After applying, lightly rake the fertilizer into the soil for better absorption.
Watering helps nutrients soak into the soil and prevents fertilizer burn. Lightly water the area with about 1/4 inch of water within 24 hours of application.
Tip: Avoid heavy watering, as it can wash away nutrients before absorption. Also, never fertilize right before a heavy rainstorm, as the runoff can lead to pollution in nearby water sources.
To protect your lawn and the environment:
Fall fertilization is an investment in your lawn’s long-term health. Following these essential steps will give your grass the nutrients it needs to grow through winter and bounce back greener than ever in spring.
However, timing, product choice, and application techniques matter. If you’re not sure about the best approach for your specific lawn, Percy’s Lawn Care is here to help.
Why Choose Percy’s?
Contact us today for expert fertilization services and ensure your lawn gets the best care this fall!
