How To Rid Crabgrass In Summer – Reclaim Your Lush Green Lawn Fast

ByRimon Chowdhury Updated on

Finding thick, sprawling clumps of weeds in your pristine turf can be incredibly frustrating. You have worked hard on your yard all spring, only to see these opportunistic invaders taking over during the hottest months.

Don’t worry—learning how to rid crabgrass in summer is entirely possible with the right approach and a little patience. I have spent years helping homeowners turn “weed patches” back into velvet-green carpets, and I can tell you that summer isn’t too late to act.

In this guide, I will share professional techniques for identifying, treating, and preventing these stubborn weeds. We will cover everything from selective herbicides to manual removal so you can enjoy a barefoot-ready lawn again.

Understanding the Summer Crabgrass Challenge

To beat this weed, you first need to understand its behavior. Crabgrass is a warm-season annual that thrives when your desired turfgrass begins to struggle under the intense July heat.

One reason it is so difficult to manage is its prolific seed production. A single plant can produce up to 150,000 seeds, which stay dormant in the soil until the conditions are perfect for a takeover.

In the summer, these plants are often in their “tillering” stage. This means they have branched out from the center, making them much more resistant to standard treatments than they were in the spring.

The Lifecycle of an Opportunist

Crabgrass seeds germinate when soil temperatures reach about 55 degrees Fahrenheit for several consecutive days. However, the visible “explosion” usually happens in mid-summer when the sun is strongest.

Because it loves the sun, you will often find it creeping along driveway edges or sidewalks. These paved surfaces radiate heat into the soil, creating a micro-environment where crabgrass flourishes while your grass wilts.

Knowing this helps you target your efforts. You aren’t just fighting a plant; you are managing the temperature and moisture levels of your soil to favor your lawn over the weeds.

how to rid crabgrass in summer: The Ultimate Guide to Post-Emergent Control

When the weeds are already visible and spreading, your best bet is a post-emergent herbicide. Unlike pre-emergents, which stop seeds from sprouting, these products are designed to kill the plant on contact.

The trick to how to rid crabgrass in summer lies in choosing a “selective” herbicide. This ensures you kill the crabgrass without harming your expensive Kentucky Bluegrass or Tall Fescue.

Look for products containing Quinclorac. This is the gold standard for residential crabgrass control because it is highly effective against mature weeds while remaining gentle on most common lawn types.

Choosing the Right Product for Your Grass Type

Before you buy any chemical, you must identify your lawn species. What works for a cool-season lawn in Ohio might completely kill a warm-season lawn in Florida.

  • Cool-Season Lawns: Quinclorac works wonders for Fescue, Ryegrass, and Bluegrass.
  • Warm-Season Lawns: Bermuda or Zoysia may require different active ingredients, such as S-Metolachlor or specialized professional blends.
  • Sensitive Grasses: Be extremely careful with St. Augustine or Centipede grass, as they are sensitive to many common weed killers.

Always read the label twice. The label is the law, and it will tell you exactly which grasses are safe for application and which will be damaged.

The Importance of Surfactants

Have you ever noticed how water beads up on a leaf? Crabgrass leaves have a slightly hairy or waxy coating that repels liquid, which can make treatments less effective.

To overcome this, many professionals use a surfactant. This is a “sticking agent” (often a methylated seed oil) that breaks the surface tension of the herbicide spray.

Using a surfactant ensures the chemical stays on the leaf long enough to be absorbed into the plant’s system. Without it, your expensive herbicide might just roll off onto the dirt.

Safe Herbicide Application in High Temperatures

One of the biggest risks when learning how to rid crabgrass in summer is the heat itself. Applying chemicals when it is too hot can result in “turf stress” or even permanent chemical burns.

Most herbicides should not be applied when air temperatures exceed 85 or 90 degrees Fahrenheit. The lawn is already struggling to stay hydrated, and the chemical load can be the “last straw” for your grass.

READ MORE  Thin Grass Lawn – Transform Your Sparse Turf Into A Lush Green Carpet

If you must treat during a heatwave, wait for a break in the weather. Early morning application is usually best, as it allows the product to dry before the sun reaches its peak intensity.

Step-by-Step Summer Spraying

  1. Check the Forecast: Ensure there is no rain expected for at least 24 hours so the product isn’t washed away.
  2. Hydrate the Lawn: Water your lawn deeply two days before treatment to ensure the grass is healthy and resilient.
  3. Spot Treat: Instead of spraying the whole yard, use a hand-pump sprayer to target only the crabgrass patches.
  4. Monitor: Watch the weeds over the next 7 to 10 days. They should begin to turn purple or brown as the Quinclorac takes effect.

Remember, mature crabgrass is tough. You might need a second application about two weeks later to completely finish off the larger, well-established clumps.

Manual Removal: The “Old School” Expert Way

If you only have a few scattered patches, or if you prefer to avoid chemicals, manual removal is incredibly effective. It provides instant gratification and removes the weed entirely from the ecosystem.

The secret to manual removal is timing. Never try to pull crabgrass when the soil is bone-dry and baked hard by the summer sun; you will likely just snap the top off, leaving the root to regrow.

The best time to pull is right after a heavy rain or a deep watering session. When the soil is saturated, the long, fibrous roots will slide out much more easily.

Tools to Make the Job Easier

While you can use your hands, a few simple tools will save your back and ensure you get the entire root system. I always recommend having a stand-up weeding tool in your shed.

  • Fiskars 4-Claw Weeder: Great for grabbing the center of the plant and pulling it straight up.
  • Hand Dandelion Weeder: A long, notched screwdriver-like tool that helps you pry the taproot loose.
  • Garden Knife (Hori Hori): Perfect for cutting around the edges of a particularly large, sprawling clump.

When you pull the weed, try to disturb the surrounding soil as little as possible. Turning over the dirt can bring buried seeds to the surface, where they will happily germinate in the newly opened space.

Pro-Active Cultural Practices to Suppress Growth

The best way to figure out how to rid crabgrass in summer is to make your lawn so healthy that the weeds have nowhere to grow. Crabgrass is a “gap filler”—it only moves in when your grass is thin or stressed.

By changing how you mow and water, you can create an environment that is hostile to weeds but perfect for your turf. This is often called “cultural control.”

Think of your lawn as a shield. If the shield is thick and tall, the sun cannot reach the soil surface to wake up those dormant crabgrass seeds.

The “Mow High” Rule

Many homeowners make the mistake of “scalping” their lawn in the summer, thinking it will mean less frequent mowing. This is a huge mistake that invites crabgrass to move in.

Set your mower blade to at least 3.5 or 4 inches. Taller grass shades the soil, keeping it cooler and preventing sunlight from reaching the weed seeds at the base.

Taller grass also develops deeper root systems. This allows your lawn to find water deep in the earth during a drought, while the shallow-rooted crabgrass begins to suffer.

Watering Deeply and Infrequently

Crabgrass has a relatively shallow root system compared to established turf. If you water your lawn for 10 minutes every day, you are keeping the surface moist—exactly what the weeds want.

Instead, water deeply (about 1 inch of water) only once or twice a week. This encourages your grass roots to grow down deep into the soil to find moisture.

The surface of the soil will dry out between waterings, which can actually desiccate young crabgrass seedlings before they have a chance to take hold.

Addressing Soil Compaction and Health

Crabgrass loves “bad” soil. If your soil is hard, compacted, and low in nutrients, your grass will struggle to grow, but crabgrass will thrive. It is often a sign that your soil needs some attention.

Compaction often happens in high-traffic areas or along the edges of paths. When the soil is packed tight, oxygen and water cannot reach the roots of your grass, causing it to thin out.

READ MORE  Lawn Edging Trench – The Professional Secret To A Crisp Garden Border

While you shouldn’t aerate in the middle of a summer heatwave, you should plan to core aerate in the early fall. This opens up the soil and allows your lawn to “breathe” again.

The Role of Soil pH

If you find that you are constantly fighting weeds despite doing everything right, it might be time for a soil test. Most turfgrasses prefer a slightly acidic to neutral pH (6.0 to 7.0).

If your soil is too acidic, your grass cannot efficiently take up nutrients, leaving it weak. Applying lime can help balance the pH, giving your lawn the competitive edge it needs to naturally crowd out the crabgrass.

A healthy lawn is the best herbicide you can ever buy. It is a living mulch that protects the soil and keeps your yard looking beautiful without constant chemical intervention.

Preparing for the Fall Transition

Once you have successfully managed the summer surge, don’t stop there. The end of summer is the perfect time to prepare for next year. Crabgrass will die off naturally with the first hard frost, but it will leave behind thousands of seeds.

In late August or September, plan to overseed your lawn. Fill in any bare spots left behind by the dead crabgrass with high-quality grass seed.

If you leave those spots bare, the crabgrass will simply return to the same spot next year. Thickening the lawn now ensures that the “real estate” is occupied by the plants you actually want.

Frequently Asked Questions About how to rid crabgrass in summer

Can I use vinegar to kill crabgrass in the summer?

While high-strength horticultural vinegar can kill the foliage of crabgrass, it is non-selective. This means it will also kill any green grass it touches. It is better used for cracks in driveways than in the middle of your lawn.

Why did my pre-emergent fail this year?

Pre-emergents often fail because of timing or weather. If you applied it too late in the spring, or if a heavy rain washed it away before it could “set,” the seeds likely germinated anyway. Also, most pre-emergents only last for 3-4 months, meaning they can wear off by mid-summer.

Is it okay to leave dead crabgrass in the lawn?

Once the crabgrass is dead from herbicide, you can leave it to decompose, but it is better to rake it out. Removing the dead plant material allows more airflow and light to reach the surrounding grass, helping it fill in the gap faster.

How long should I wait to mow after treating for crabgrass?

Generally, you should wait at least 24 to 48 hours after applying a liquid herbicide before mowing. This gives the plant enough time to absorb the chemical through its leaves and transport it to the roots.

Conclusion

Mastering how to rid crabgrass in summer is a rite of passage for many dedicated gardeners. It requires a mix of immediate action and long-term strategy, but the results are well worth the effort.

Remember to focus on selective herbicides like Quinclorac for big patches, and don’t underestimate the power of a good weeding tool after a summer rain. Most importantly, keep your mower height high and your watering deep to ensure your grass stays the “king of the hill.”

Don’t let a few weeds ruin your summer enjoyment. With these tips, you can reclaim your lawn and keep it looking lush and green all season long. Go forth and grow!

Rimon Chowdhury
Latest posts by Rimon Chowdhury (see all)

Similar Posts