How to Kill Crabgrass and Prevent It from Returning


Many homeowners detest crabgrass because of its typical shade of green which is different from the lush lawns. Furthermore, this type of grass steals valuable nutrients and water from the desirable lawn, making it difficult for your lawn to grow.

That’s why you need to learn how to kill crabgrass and prevent it from reappearing. This article offers you a complete guide on how to get rid of crabgrass.

What Is Crabgrass?

What Is Crabgrass

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Also referred to as Digitaria, finger-grass, and fonio, crabgrass is a group of plants in the grass family native to hot and warm temperate regions, but it can also occur in tropical, subtropical, and cooler temperate regions.

This plant is referred to as crabgrass because it grows low to the ground with stalks that emerge from the center of the grass clump, reminiscent of crab legs. It is a slender monocotyledonous annual plant that is often considered a lawn pest.

Crabgrass is normally distinguished by its long, finger-like inflorescences. A single patch of crabgrass in a nicely kept lawn sticks out like a swollen thumb. Although this grass is normally found on lawns, it is not good for lawns. Also, while the types of grass that are suitable for lawns are perennial, crabgrass is an annual grass.

It is also important to note that crabgrass seeds hidden in the soil start to germinate in spring when temperatures in the soil rise above 55 degrees. Therefore, if you want to eliminate this weed from your lawn, you have to do early spring crabgrass prevention. Usually, the lifecycle of this plant starts when a seed in the soil cracks open and successfully goes through the germination phase.

The plant will then grow and spread its stalks in spring, summer, and fall. During this period, the plant will produce seeds. But when it becomes extremely cold in winter, the plant will die. And although the plant won’t reappear again after the cold season, it leaves thousands of seeds in the ground to carry on the cycle into the subsequent spring.

What Does Crabgrass Look Like?

Look Like

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Much like an ocean crab, crabgrass has many legs (stems) and is stumped to the ground. One of the reasons why this plant is so stubborn is its procumbent growth pattern. This means that the plant cannot grow upright unless it’s aided by humans through training. Generally, crabgrass has wide, flat blades, and produces long flower bunches and thousands of seeds per season.

It shouldn’t surprise you to learn that there are two main types of crabgrass: smooth crabgrass and hairy crabgrass. The hairy type of crabgrass has many tiny hairs on its stems and leaves. But this doesn’t mean that the smooth type doesn’t have hair. It does have a few tiny hairs, but only at its auricles – tiny, ear-like outcrops at the base of the leaves.

When fully grown, the leaves of smooth crabgrass are about 5 inches long and its stems bend at the nodes and at times turn red. Smooth crabgrass is smaller than hairy crabgrass.

Is Crabgrass Bad for Your Lawn and Why?

Bad for Your Lawn

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Although crabgrass is an annual grass, only surviving a single season every year, it can have devastating effects on your lawn if not handled properly. For instance, if you allow a single plant to mature, it will produce close to 150,000 seeds every year. Moreover, this is an opportunistic plant that is always striving to take a base in the lawn.

Once it has fully established itself in your lawn, you will have a hard time getting it out of there. You will have to come up with a careful and dependable countermeasure to reduce or eliminate it from your lawn. Unfortunately, this annual weed can grow even in the toughest weather conditions. This makes it a menacing adversary in an ordinary home lawn.

While most perennial grasses that are desirable for lawns do well in cool and warm climates, crabgrass can withstand extreme heat and drought conditions. That’s why you will find it growing out of cracks in your driveway, compressed dirt, and gravel, where no other plant can survive. Crabgrass is particularly ruthless to thin lawns or small patches that have been decimated by insects.

This weed is always looking to monopolize open and susceptible spaces, especially in spring and summer. If left unchecked, either before or after germination, this weed will wind up being an uncontrollable summer-time plant in your lawn.

But your lawn can resist severe crabgrass invasion by developing a thick canopy with a mowing height of above 3 inches. And if the crabgrass germinates on the edges of your walkway, you can effectively treat them when small to prevent a full-blown crabgrass invasion.

How to Get Rid of Crabgrass

Get Rid of Crabgrass

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There are different ways to get rid of crabgrass on your lawn. For instance, you can the various aggressive herbicides available to eliminate the weed or use non-chemical techniques that are also highly effective.

Sometimes even uprooting young crabgrasses helps to control the invasion. Here are some of the most effective ways to eliminate and prevent crabgrass from reappearing.

1. Suffocate the Crabgrass

You can easily eliminate crabgrass by covering it with bricks, tiles, plates, or any other object that can help to block the weed from accessing sunlight. Cover the weed for about 4 to 6 weeks so that it can be completely suffocated to death. Once the weed is dead, uproot it and rake the surface where the crabgrass was and reseed it with desirable turf seeds.

2. Use Boiling Water

You can eliminate unwanted weeds like crabgrass by pouring hot, sweltering water on and around it. Make sure the water covers up to a 3-foot radius to get to the root system. However, bear in mind the fact that the boiling water will also destroy your healthy grass and any other plant around the crabgrass.

3. Use Gardening Vinegar

Vinegar has proved to be an all-natural method that kills crabgrass without causing permanent damage to the soil. Just spray the vinegar with a 5 percent acidity or higher on the crabgrass until it’s completely soaked. Repeat the application several times for several days, weeks, or until the weed dies.

4. Use Organic Herbicidal Soap

Simply spray the herbicidal soap on crabgrass until it’s soaked. However, you need to use this soap carefully because it can easily damage any grass or plants around the weed. Once the crabgrass is dead, remove it from the lawn, patch, and reseed the empty spaces as needed.

Ways to Prevent Crabgrass from Reappearing

Prevent Crabgrass from Reappearing

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There are several ways to ensure that crabgrass does not monopolize your lawn. But all these methods come down to following the right lawn care basics to create a healthier, robust lawn that can resist the weed.

• Mow high: Keep your lawn healthy and thick by mowing high. Do not remove more than ⅓ of grass blades when moving. This helps to reduce spaces for the weed to grow.
• Be hands-on with weeds: Always pull or treat the weed in the spring before it gets an opportunity to spread and mature. You can use a weeding tool (or even a screwdriver) to uproot the weed from your lawn.
• Overseed: This is an important landscaping method that is key to crowding out the weed and other unwanted plants in your cool-season lawn.
• Controlled watering: You should water your lawn less frequently but deeper to promote longer, healthier root growth for your desirable lawn. This technique helps to dry out the shallow-rooted weeds like crabgrass.
• Aerate: You ventilate your soil regularly to prevent compaction. Some weeds like crabgrass can thrive in compressed soil while turfgrass cannot. Therefore, aerate your lawn regularly to ensure your soil is getting enough oxygen and nutrients to help your lawn grow healthier and thicker. That way, the canopy will smother the weeds.

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Carrie Nelson
Carrie Nelson wears many hats. She’s an avid quilter, author as well as a social media guru. Her love for quilting is evident in her books on the subject and she hopes to pass on her color balance and design skills to her readers. When not quilting or writing, you’ll find her knee-deep in home improvement projects.