For cool-season lawns, fall isn't an epilogue to summer—it's the main event. While spring gets all the attention, fall's blend of warm soil and cool air triggers your lawn's most critical period of growth. It's now that your grass shifts its focus from growing blades to building deep roots and storing energy for winter.
This guide outlines the three key strategies to support this natural process:
- Feeding for deep roots
- Seeding for a denser turf
- Weeding for a clean slate
Mastering these steps now means a more resilient lawn and less work for you next spring.
Sunday Tip:
Want personalized fall advice? Ask Sunny to review your plan and give you tailored tips based on your specific lawn data and past applications.
Watch our new video guide to see these fall strategies in action.
The three pillars of fall lawn care for cool-season grasses
Think of your fall lawn care as a synergistic system. Each step you take reinforces the others, helping you grow a lawn that’s not just surviving, but thriving.
1. Feed for deeper roots (aka fertilizing)
The goal of fall fertilizing isn't to create a burst of green top-growth. It's to work with your lawn's natural shift in focus. In the fall, cool-season grass redirects energy from its blades to its root system to store nutrients for winter.
The right Sunday fall fertilizer supports this critical process.
- What to use: A nitrogen- and iron-based fertilizer without phosphorus (P) or potassium (K) is ideal. Nitrogen fuels root development and energy storage, while iron provides a rich green color without forcing delicate new growth before the first frost.
Fall Fortify Plus Micronutrients Lawn Fertilizer
- 22-0-0 NPK lawn fertilizer
- Fall greening and rooting
- Resist winter injury
- Zero pesticide formula
- When to apply: Your personalized application window is in your My Plan, but for a quick answer, just Ask Sunny, "When should I apply my fall fertilizer?" to get your exact date.
Sunday Tip:
The best time to fertilize your lawn is typically late August to mid-October, when your grass is still actively growing. Applying during this time helps nutrients fully absorb and get to work before the ground freezes.
2. Seed for a denser lawn
Fall grass seeding is the ultimate integrated pest management (IPM) strategy. A dense lawn leaves no room for pesky weeds to establish in the spring. So, you’re not just repairing summer damage, you’re proactively building a weed-resistant lawn.
- What to use: The best part about cool-season grasses is that they are designed to blend, allowing you to mix and match different types of seed for various lawn areas or uses.
- Fescue Rescue is perfect for patching thin areas in sun or shade
- Pet Lawn is designed to stand up to wear and tear.
- Shade Select is the perfect choice for shady areas of the lawn.
- Kentucky’s Best is for emerald green northern lawns.
- Lucky Lawn is made for pollinator-friendly, clover-loving lawns.
- How to do It: For widespread thinning, overseeding is your best bet. Here’s how to seed in a few steps: mow your existing lawn a little shorter than usual (around 2 inches), make sure the seed makes good contact with the soil, and water lightly every day until the new grass sprouts.
Sunday Tip:
Not sure which seed is right for you? Sunny knows your location and lawn data. Ask Sunny, "What's the best grass seed for my lawn?" for a personalized recommendation.
3. Weed control for a clean slate
Fall is when many perennial weeds are at their most vulnerable, because they are actively sending nutrients down to their roots for winter storage. When you apply a spot treatment now, the product is more effectively transported to the root, killing the weed for good.
- What to use: Use an iron-based selective herbicide like Dandelion Doom to target broadleaf weeds without harming your lawn. For weeds in cracks or on patios, Weed Warrior is the right tool.
- Why It matters: Removing weeds now prevents them from stealing critical nutrients from your grass and helps establish your new seed with little to no competition for space and sunlight.
Your Sunday cool-season fall toolkit
Ready to get started? Equip your lawn with everything it needs to build strength and density this fall. As a loyal Sunday member, use discount code FALLSAVINGS to get 40% OFF these fall essentials:
- For fertilizing: Fall Fortify Plus Micronutrients
- For seeding: Fescue Rescue, Pet Lawn, Bare Repair Sun & Shade
- For weeding: Dandelion Doom Starter Kit, Weed Warrior Starter Kit plus refill packs, too!
By following these three steps, you're making the smartest play for next spring's lawn—and Sunny can help you track your progress along the way.
Let's get growing
Our lawn engine uses satellite data to map out your lawn size and determine things like average rainfall, common weeds, and pest activity.
