Crabgrass is a notorious lawn invader that frustrates homeowners every summer. As an annual weed, it thrives in bare spots and compacted soil, quickly spreading its seeds to take over your lawn. If left unchecked, crabgrass can ruin the appearance and health of your turf. Fortunately, late summer and fall are the perfect seasons to target this pesky weed and prevent it from coming back. In this article, we’ll explore three simple yet effective strategies to stop crabgrass for good, leaving you with a lush, healthy lawn next season.
Understanding Crabgrass and Its Life Cycle
To effectively combat crabgrass, it’s essential to understand its life cycle. Crabgrass is an annual weed, meaning it germinates, grows, produces seeds, and dies within a single year. Seeds usually sprout in late spring when soil temperatures reach 55–60°F, and the plant thrives during the hot summer months. By late summer and early fall, crabgrass begins to set seeds, ensuring its return the following year.
The key to eliminating crabgrass is to disrupt its cycle—killing existing plants and preventing seed production. Timing is critical, and targeting crabgrass in late summer and fall ensures you stop it before it spreads seeds.
3 Simple Tips to Kill Crabgrass in Late Summer & Fall
1. Mow High and Bag Clippings
Mowing your lawn correctly can make a significant difference in controlling crabgrass. Crabgrass thrives in short, thin lawns where it has access to sunlight and space to grow. By mowing high and maintaining a dense lawn, you can shade out the weed and prevent it from reseeding.
- Set Your Mower Height: Keep your mower blades at 3–4 inches. Taller grass shades the soil, making it harder for crabgrass seeds to germinate.
- Bag Your Clippings: If crabgrass is already present, bag your clippings to prevent spreading its seeds around your lawn. Composting these clippings is not recommended, as the seeds can survive and spread further.
- Avoid Scalping: Scalping your lawn (cutting it too short) creates bare spots that crabgrass can quickly exploit. Always leave enough grass height to promote healthy turf growth.
2. Apply Post-Emergent Herbicide
If crabgrass is actively growing, a post-emergent herbicide is your best weapon. These herbicides are designed to kill mature crabgrass plants without harming your established lawn. Late summer and early fall are ideal times for application, as the weed is still actively growing.
- Choose the Right Product: Look for a post-emergent herbicide labeled specifically for crabgrass. Ensure it is safe for your grass type (e.g., cool-season or warm-season grasses).
- Apply Properly:
- Apply the herbicide on a dry, calm day when no rain is expected for at least 24 hours.
- Follow the manufacturer’s instructions carefully to avoid overapplication, which could damage your lawn.
- Spot Treatment: Focus on areas where crabgrass is most prevalent. This targeted approach minimizes chemical use and protects the rest of your lawn.
3. Seed Bare Patches to Crowd Out Crabgrass
Crabgrass loves bare spots and compacted soil. Filling in these areas with grass seed during the fall not only eliminates space for crabgrass but also strengthens your lawn’s overall health.
- Prepare the Soil: Rake bare spots to remove debris and loosen the soil. For compacted areas, aerate the soil to improve drainage and root penetration.
- Choose the Right Seed: Select a high-quality grass seed that matches your lawn type and climate. For example, use cool-season grasses like Kentucky bluegrass or fescue in northern areas.
- Overseed Thin Areas: Spread seed over bare or thin spots and lightly cover it with topsoil or compost. Water thoroughly to help seeds germinate.
- Water Consistently: Keep the soil moist until the new grass is well-established. Avoid overwatering, as it can lead to fungal issues.
Bonus Tips for Long-Term Crabgrass Prevention
While the three tips above are excellent for addressing crabgrass in late summer and fall, maintaining a healthy lawn year-round is key to long-term prevention. Here are some additional tips to keep crabgrass at bay:
- Apply a Pre-Emergent Herbicide in Spring:
- Pre-emergent herbicides stop crabgrass seeds from germinating. Apply it in early spring when soil temperatures reach 50°F, usually around the time forsythias bloom.
- Fertilize Your Lawn:
- A well-fed lawn is more competitive against weeds. Use a slow-release fertilizer in the fall to promote root growth and strengthen your turf for the next season.
- Water Deeply and Infrequently:
- Deep, infrequent watering encourages deep root growth in grass, making it more resilient to stress and weeds. Avoid shallow, frequent watering, which promotes weed growth.
- Maintain Lawn Density:
- Dense grass prevents sunlight from reaching the soil, which inhibits crabgrass germination. Regular overseeding and proper mowing practices ensure your lawn remains thick and healthy.
- Remove Weeds by Hand:
- For smaller infestations, hand-pulling crabgrass can be effective. Make sure to remove the entire root system to prevent regrowth.
Common Mistakes to Avoid
While combating crabgrass, it’s important to avoid common mistakes that can undermine your efforts:
- Delaying Treatment: Waiting too long to address crabgrass allows it to spread seeds, making next year’s infestation worse.
- Incorrect Herbicide Use: Using the wrong product or applying it at the wrong time can harm your lawn. Always read labels and follow instructions.
- Ignoring Bare Spots: Neglected patches of bare soil are invitations for crabgrass to take over. Always address bare areas promptly.
Why Late Summer & Fall Are Crucial
Targeting crabgrass in late summer and fall provides several advantages. During this time, the weed is actively producing seeds, making it the perfect opportunity to disrupt its cycle. Additionally, fall is the ideal season for lawn repair and reseeding, allowing you to create a stronger, weed-resistant lawn for the following year.
Conclusion
Crabgrass may be stubborn, but with the right approach, you can stop it for good. By mowing high, applying post-emergent herbicide, and reseeding bare spots, you can tackle this weed effectively in late summer and fall. Combine these strategies with proper lawn care practices, and you’ll enjoy a lush, healthy lawn free of crabgrass year after year.
Take action today and reclaim your lawn from crabgrass! Have you tried any of these tips? Share your results or your favorite lawn care tricks in the comments below.