Fall is one of the best times for lawn care. After a long summer, your grass needs help recovering, and it’s also prepping for winter. Applying fertilizer in fall helps strengthen roots, boost density, and reduce weeds.
But when’s the best time to do it, and what kind of fertilizer should you use? Here’s what you need to know to get the timing right and give your grass the best shot at thriving.
Why Fall Fertilization Matters
Thanks to summer heat and foot traffic, your lawn is likely worn out. Fall is when grass naturally shifts energy below the surface, building up its root system. Fertilizer at the right time supports this process, helping it recover and store nutrients before winter dormancy.
“Even healthy lawns need the right nutrients to stay strong and resilient," shared Matthew Koch, Ph.D., Director of Biotechnology, Genetics, and Seed at Scotts. "Even if your lawn looks fine now, the soil can gradually lose nutrients. Fertilizing ensures your grass receives the right balance of nourishment, preventing nutrient deficiencies and future decline. Plus, the added density helps crowd out weeds naturally.”
If you have cool-season grasses like Kentucky bluegrass, tall fescue, or perennial ryegrass, fall fertilization is especially important. These types grow most actively in spring and fall, making fall the perfect time to feed them.
Warm-season grasses like Bermuda grass grow best in summer but can still benefit from a light fall application in some regions.
When to Apply Fall Weed and Feed
The best time to apply fall weed and feed is early fall. We usually aim for between early September and mid-October, but like everything related to lawn care, it really depends on your region. You need to find the right window that gives the product time to kill broadleaf weeds like dandelion while also feeding your lawn. Wait until daytime temps are consistently between 60°F and 75°F. That’s when weeds are still active, and your grass is still growing.
Don’t apply weed and feed too late in the season. Once your lawn goes dormant, it won’t absorb nutrients or herbicides efficiently.
What Fertilizer to Use in Fall
For most lawns, a slow-release nitrogen fertilizer is the best choice in fall. Look for one with a balanced NPK formula—something like a 24-0-6 or 29-0-5 blend. These support root growth without pushing too much top growth. Scotts® Turf Builder® WinterGuard® Fall Lawn Food is one example designed for this purpose.
Some fall fertilizers are labeled “Winterizer” or “Fall Lawn Food.” These are made to help grass store energy for the winter and kickstart growth in early spring. You don’t need a high-phosphorus starter fertilizer unless you’re seeding a new lawn.
If you're not sure what your lawn needs, consider doing a soil test. Soil testing can tell you if you're low on any nutrients or if your soil pH is off. That way, you’re not guessing.
If your main concern is weed control, you can choose a weed and feed product instead. Just make sure it matches your grass type. Not all formulas are safe for all lawns, especially if you have warm-season grasses.
When to Spread Fall Fertilizer
Think of this as the first step towards winter preparation: Aim to fertilize about 6 to 8 weeks before your average first frost. That usually means sometime at the end of the summer season between Labor Day and mid-October, depending on your climate zone. Don’t wait too long; however, don’t apply too early either. Early September is often perfect for many cool-season lawns.
The time of day also matters. Apply fertilizer in the morning or late afternoon when it's cooler. Avoid applying it during the heat of the day, especially if using granular fertilizer, as this increases the risk of fertilizer burn.
Water your lawn lightly after applying fertilizer unless the label says otherwise. This helps the nutrients soak into the soil and reach the grass roots.
FAQ
Can I apply fall fertilizer and seed at the same time?
It depends on the product. Most weed and feed products shouldn’t be used when seeding, as the herbicide can prevent new seeds from growing in bare areas. If you're planning to seed in fall, skip the weed and feed and choose a starter fertilizer designed for new grass. Always check the label.
What happens if I fertilize too late in fall?
Fertilizing too late (after your grass has reached its dormant season) won’t do much good. The nutrients may wash away, and you’ll risk snow mold or wasted product. The roots won’t absorb fertilizer when the grass stops growing. Stick to that 6-8 week-before-frost rule to avoid causing lawn issues.
