How To Rid Crabgrass In Summer – Your Expert Guide To Eradicating

The Summer Crabgrass Battle: Understanding Your Adversary

It’s that time of year again. You’ve nurtured your lawn, admired its lush green carpet, and then, like an unwelcome guest, it appears: the tell-tale patches of coarse, light-green grass that just don’t belong. That’s crabgrass, an annual weed that thrives in the heat and humidity of summer, and it can quickly take over a healthy lawn if left unchecked.

Many homeowners face this frustrating reality. You might have applied pre-emergent herbicides in the spring, thinking you were safe, only to see those familiar, sprawling stems popping up. This is where understanding the crabgrass life cycle becomes critical. Crabgrass seeds germinate when soil temperatures consistently reach the mid-50s Fahrenheit, often in late spring. By the time summer arrives, these seedlings have matured into significant, seed-producing plants that will continue to spread and contribute to next year’s problem.

This guide will equip you with the knowledge and practical steps to effectively tackle crabgrass when it’s at its most visible and aggressive. We’ll cover everything from manual removal to chemical solutions and, importantly, how to prevent its return. By the end of this article, you’ll be well-prepared to reclaim your lawn’s beauty and health, ensuring a more enjoyable summer outdoors.

When to Act: Recognizing Crabgrass in Its Summer Prime

Summer is the prime time to identify and combat crabgrass because that’s when it’s most conspicuous. You’ll notice it as clumpy, spreading patches that are distinctly different from your desirable turfgrass. Its leaves are wider and lighter green, and the plant grows horizontally, often forming a low-lying mat.

Pay attention to areas that receive full sun, as crabgrass thrives in these conditions. Bare spots, compacted soil, and thin turf areas are also common hiding places. Don’t wait until the infestation is widespread; early detection is key to easier eradication.

Manual Removal: The First Line of Defense

For smaller infestations, or if you prefer an organic approach, manual removal can be highly effective. The best time to pull crabgrass is after a rain or a good watering, when the soil is soft and the roots are less likely to break.

The Art of the Pull

1. Get Down to the Roots: Grasp the weed firmly at its base, as close to the soil line as possible.
2. Wiggle and Lift: Gently wiggle the plant back and forth to loosen the soil around the roots before pulling it straight up.
3. Inspect for Stragglers: Make sure you’ve removed the entire root system. Crabgrass can re-root from stem nodes if pieces are left behind.
4. Dispose Properly: Bag the pulled weeds and discard them. Leaving them on the lawn can allow seeds to spread.

This method is labor-intensive but offers immediate results without the use of chemicals. It’s also a great way to get some exercise while tending to your lawn.

Chemical Solutions: Targeted Approaches for Summer Crabgrass

When manual removal isn’t feasible due to the extent of the infestation, chemical treatments become a necessary consideration. It’s crucial to understand that post-emergent herbicides are your primary tool for summer crabgrass control. Pre-emergent herbicides work by preventing seeds from germinating, making them ineffective once the plant has already sprouted.

Understanding Post-Emergent Herbicides

Post-emergent herbicides are designed to kill actively growing weeds. For crabgrass, you’ll want to use a selective herbicide, meaning it targets specific types of weeds (like crabgrass) without harming your desirable lawn grasses.

Common active ingredients to look for include:

• Quinclorac: Highly effective against crabgrass and many other common lawn weeds. It’s generally safe for most cool-season turfgrasses and some warm-season varieties.
• Fenoxaprop-p-ethyl: Another effective option for crabgrass control. It’s important to check the label for compatibility with your specific lawn type.
• MSMA (Monosodium Methanearsonate): Historically effective, but its use is restricted or banned in many areas due to environmental concerns. If available and permitted in your region, use it with extreme caution.

Application Is Key: Safety and Efficacy

Always read and follow the product label instructions meticulously. This is not just for effectiveness but also for safety.

1. Timing is Crucial: Apply post-emergent herbicides when crabgrass is young and actively growing. The younger the weed, the more susceptible it is to the herbicide.
2. Weather Matters: Avoid applying herbicides on windy days to prevent drift onto desirable plants or neighboring properties. Do not apply when temperatures are expected to exceed 85-90°F (29-32°C), as this can damage your lawn grass.
3. Proper Mixing and Application: Use a calibrated sprayer for accurate application. Mix the herbicide according to the label directions. Over-concentrating can damage your lawn; under-concentrating will be ineffective.
4. Watering Considerations: Some herbicides require the soil to be moist for absorption, while others are best applied to dry foliage. Check the label for specific watering instructions before and after application.
5. Repeat Applications: Some treatments may require a second application after a specified interval (usually 7-14 days) for complete eradication.

Improving Lawn Health: The Long-Term Strategy

While immediate solutions are necessary, the most sustainable way to rid your lawn of crabgrass is to create an environment where it cannot thrive. A dense, healthy lawn is the best defense against invasive weeds.

Mowing Height: Don’t Cut Too Short

• Higher is Better: Mowing your lawn at the higher end of the recommended height for your grass type (typically 3-4 inches for most cool-season grasses) helps shade the soil. This inhibits crabgrass seeds from germinating by reducing sunlight exposure.
• Sharp Blades: Always use a sharp mower blade. Dull blades tear grass, creating ragged edges that are more susceptible to disease and stress. Sharpen your blades at least once annually.

Watering Wisely: Deep and Infrequent

• Encourage Deep Roots: Water your lawn deeply but infrequently. This encourages grass roots to grow deeper, making the lawn more drought-tolerant and better able to outcompete shallow-rooted weeds like crabgrass.
• Avoid Frequent, Light Spritzes: Light watering encourages shallow root systems and can create ideal conditions for weed seeds to germinate. Aim for about 1 inch of water per week, either from rainfall or irrigation.

Fertilization: Feeding Your Lawn Right

• Balanced Nutrition: A well-fertilized lawn is a strong lawn. Use a balanced fertilizer with an NPK ratio appropriate for your grass type and the season. A slow-release fertilizer is often preferred for sustained feeding.
• Timing is Key: Fertilize at the appropriate times for your grass type. For cool-season grasses, this usually means spring and fall. Avoid over-fertilizing, which can encourage weak, rapid growth that is more prone to disease and weed invasion.

Aeration and Dethatching: Breathing Room for Your Turf

• Aeration: Core aeration removes small plugs of soil, improving air circulation, water penetration, and nutrient uptake. This is particularly beneficial for compacted soils, which are prime real estate for crabgrass. Aerate in the fall or spring.
• Dethatching: A thick layer of thatch (dead grass stems and roots) can smother your lawn and harbor pests and diseases. Dethatch when the thatch layer exceeds 1/2 inch. This process opens up the turf canopy, allowing for better soil contact for treatments and promoting healthier growth.

How to Rid Crabgrass in Summer: A Comprehensive Step-by-Step Plan

To truly tackle crabgrass, especially when it’s already established in summer, you need a strategic, multi-faceted approach. This plan integrates immediate action with long-term lawn health improvements.

Phase 1: Immediate Intervention (Summer Focus)

1. Identify and Assess: Walk your lawn, noting the extent of the crabgrass infestation. Differentiate it from your desirable turf.
2. Manual Removal (Small Infestations): For scattered patches, pull the crabgrass by hand, ensuring you remove the entire root system. Bag and dispose of it.
3. Post-Emergent Herbicide Application (Larger Infestations):
   • Choose a selective post-emergent herbicide labeled for crabgrass control and safe for your lawn type.
   • Read and follow all label instructions regarding mixing, application rates, and safety precautions.
   • Apply when crabgrass is actively growing and temperatures are moderate (below 85°F/29°C).
   • Consider a second application if the label recommends it, usually 7-14 days later.
4. Spot Treatment: If you have only a few stubborn patches that survived initial treatment or manual pulling, consider using a ready-to-use spot treatment herbicide for targeted application.

Phase 2: Mid-to-Late Summer Lawn Care

1. Maintain Proper Mowing: Continue mowing at the higher recommended height for your grass type.
2. Water Deeply: Ensure your lawn receives adequate water, but avoid overwatering.
3. Monitor for Regrowth: Keep an eye out for any returning crabgrass or new seedlings. Address them promptly with manual removal or spot treatments.

Phase 3: Fall Preparation for Next Year’s Prevention

1. Overseeding (If Necessary): If your crabgrass infestation has left significant bare patches, fall is the ideal time to overseed with a high-quality grass seed mixture. This helps create a denser turf for the following spring.
2. Core Aeration: Improve soil structure and reduce compaction.
3. Dethatching: Remove any excess thatch buildup.
4. Fall Fertilization: Apply a balanced fall fertilizer to promote root development and overall lawn vigor.
5. Pre-Emergent Planning: While it’s too late for this year, start researching and planning for spring pre-emergent applications. Understanding the ideal timing for your region is key to preventing crabgrass germination next season.

Dealing With Stubborn Patches and Re-Seeding

Sometimes, even with diligent effort, crabgrass leaves behind unsightly bare or thin patches. Fall is the perfect time to address these areas.

Re-Seeding Bare Spots

1. Prepare the Soil: Loosen the soil in the bare patch with a rake. Remove any debris or remaining crabgrass roots.
2. Choose the Right Seed: Select a high-quality grass seed blend that matches your existing lawn. Consider a mix that includes a slow-release starter fertilizer.
3. Spread the Seed: Distribute the seed evenly over the prepared area. Follow the seeding rate recommended on the bag.
4. Lightly Rake and Cover: Gently rake the seed into the top 1/4 inch of soil. This ensures good seed-to-soil contact.
5. Water Consistently: Keep the seeded area consistently moist until the new grass is established. This often requires light watering multiple times a day for the first couple of weeks.
6. Protect the Area: If possible, keep foot traffic and pets off the newly seeded area until the grass is well-established and has been mowed a few times.

Frequently Asked Questions About Crabgrass in Summer

Q1: Can I Still Use Pre-Emergent Herbicides in Summer to Stop Crabgrass?

A1: No, pre-emergent herbicides are designed to prevent seeds from germinating. By summer, crabgrass seeds have already sprouted, so pre-emergents will not be effective. You need to use post-emergent herbicides or manual removal at this stage.

Q2: My Lawn Is Mostly Crabgrass. Is It Worth Trying to Save It?

A2: If your lawn is heavily infested, especially with older, established crabgrass plants, it might be more effective to kill the entire lawn and start over in the fall with a new seeding. However, for moderate infestations, a combination of post-emergent treatment and diligent lawn care can help you regain control.

Q3: How Can I Prevent Crabgrass From Coming Back Next Year?

A3: The best prevention is a healthy, dense lawn. This includes proper mowing height, deep watering, appropriate fertilization, and timely application of pre-emergent herbicides in early spring, before soil temperatures reach the critical germination point. Aeration and dethatching in the fall also contribute to a more resilient turf.

Q4: Are There Any Organic Ways to Get Rid of Crabgrass in Summer?

A4: Organic methods primarily involve manual pulling and improving lawn health. Corn gluten meal can act as a pre-emergent in early spring, but its effectiveness as an organic post-emergent in summer is limited. Focusing on creating a thick turf through proper care is your best organic strategy for long-term control.

Conclusion: A Greener Future for Your Lawn

Successfully managing and eradicating crabgrass in summer requires a combination of immediate action and consistent, long-term lawn care. By understanding how this invasive weed thrives and implementing a strategic approach that includes manual removal, appropriate herbicide use, and, most importantly, fostering a robust and healthy turf, you can significantly reduce its presence.

Don’t get discouraged if you don’t achieve perfect results immediately. Lawn care is an ongoing process. Focus on the steps outlined here, and you’ll be well on your way to a lusher, greener lawn that can naturally outcompete crabgrass and other unwanted invaders. Enjoy your beautiful, healthy lawn!

Taylor Galla Founder of Garden Aider

• Mechanical engineer
• Gardening since 2010
• Univ. of Nevada, Reno

From the author's notebook

Taylor pairs an engineer's eye with years of hands-on work in soil, lawns and outdoor machinery. He tests ideas in his own garden, keeps tractors and mowers running himself, and speaks to local horticulture groups. Every Garden Aider guide is written to be practical, accurate and safe to follow.

“To bring life alive, you just need to mix some love with the compost, bedding, and gardening machines.”

Published Jun 16, 2026