How to Kill Crabgrass

Battle this lawn enemy with these tips.

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Crabgrass is a Lawn's Worst Enemy

Crabgrass is a Lawn's Worst Enemy

Crabgrass is a lawn's worst enemy.

Photo by: Image courtesy of Macleay Grass Man.

Image courtesy of Macleay Grass Man.

Crabgrass is a lawn's worst enemy.

Plagued by crabgrass? You’re not alone. This ugly weed is pervasive and common, and is probably taking over multitudes of yards on your block right this minute.

True to its moniker, crabgrass (Digitaria sanguinalis) is a true grass…but it tends to look out of place amid turf grasses. It’s characterized by rough, pointy, light-green blades that grow in clumps that spread aggressively.

As the plant ages, it sends out thousands of seeds. Just one seed dropped by a bird in flight can result in thousands of plants in a single season! And while crabgrass loves the sun, it’s hardy and adaptable and can grow in poor, dry soil and shade.

So how to win against such a persistent weed? 

Launch an Attack Early

Clumps can be pulled easily in spring, when they have shallow roots. But by the time crabgrass has taken a hold on your yard come summer, you’ll need to turn to chemical methods – which are not always effective, and may leave ugly patches of dead crabgrass in their wake - or just wait for the plant to die out over the winter and then try to prevent its reappearance next year.

Prevention Is Key

Crabgrass preventatives work by keeping seeds from germinating before the grass even starts to grow and should be used as soon as the ground reaches 60 degrees and stays there for a few days – generally around the first of May, depending on your climate. They’re effective for about a month, and you’ll need to wait at least three weeks after treatment to plant grass seed. A crabgrass preventer meant for lawns will do less damage to your desired turf.

Care For Your Lawn

A thick, luxuriant bed of grass is the best crabgrass deterrent. Crabgrasses grow best in sparse lawns with short, thin grass. Mulch, fertilizer, enough water and grass that’s at least 2 ½ inches long can help squelch crabgrass’s progress.