How To Kill Crabgrass (Kill And Prevent Crabgrass)

Picture this: It’s mid-Spring and your lawn is looking immaculate.

You’ve poured hard work and sweat into tending to your emerald-green yard and it’s finally starting to pay off as the weather gets warmer.

Upon closer inspection, however, you see a strange, off-colored blade of green grass pop up.

Before you know it, there’s a whole patch of crabgrass growing in your lawn, threatening to ruin your lush Kentucky Blue pastures.

Unfortunately, crabgrass isn’t easy to get rid of.

It can flourish in most weather conditions and doesn’t respond to combination herbicides either.

It sprouts quickly and can spread even faster. It’s also garish in color and easy to see, creating a yellow stain on an otherwise perfect green oasis.

Crabgrass can also be detrimental to your lawn’s health, taking away crucial nutrients that the regular grass needs to grow thick and tall.

Luckily, there are several good ways to get rid of crabgrass quickly and effectively.

It can take a bit of planning and preparation, but this guide will outline several ways to kill crabgrass and prevent it from showing back up again.

You can weed by hand, use a combination of chemical weed killers, call a professional to do a deep treatment, or try a couple of unconventional methods.

Calling a lawn professional may be the best option if you’re unsure of where to start, but if you feel confident in your weeding skills and are ready to get your hands dirty, then go ahead and get started.

What is crabgrass?

To understand how to kill crabgrass, you should first understand what it is.

Crabgrass is an annual, super-abundant weed and a type of grass, as the name suggests.

Unlike regular grass, which is perennial (meaning the grass can survive for decades), crabgrass does not survive from year to year.

This means that, fortunately, you can get ahead of the crabgrass growth cycle before it begins.

All year-round, there may be thousands of crabgrass seeds in the soil just waiting to pop up and call your lawn home.

In the spring, when temperatures begin to reach over 55 degrees, some of these seeds will begin to germinate, or start growing.

Once they crack open, there’s no stopping the growing process.

Its growth will begin during the spring and carry over into the summer and fall.

As the crabgrass grows and spreads, it produces even more seeds.

Once the weather turns cold in late fall, the reign of terror of this pesky plant will finally stop.

But, not after spreading thousands of new seeds on your lawn that are sure to sprout next spring.

This vicious cycle is not only annoying but to put it simply, looks pretty ugly.

So how can you take back your lawn?

There are several different ways.

Hand-weeding

If you’re prepared to get your hands dirty and put in some serious elbow work, you can weed out the crabgrass by hand.

You’ll have to pull out each individual crabgrass by the root, the surest way to know you’re getting the entire weed out for good.

Be prepared to put aside some time to do this though, as it’s not the easiest route.

Start by using a basic garden weeder tool (found at most hardware stores) and drive deep under the ground and under the roots of the crabgrass.

Once you get it up, place the clumps in an air-tight trash bag and seal it tight, ensuring none of the seeds spread as you weed.

Be aware that young crabgrass is easier to pull, with two to four sets of leaves but no splayed seed heads.

Matured crabgrass, with three or four rows of leaves, may be harder to get out by hand and call for stronger treatment.

Use a chemical treatment

If you’d like to take the topical route, use a herbicide application to get rid of crabgrass.

You’ll usually be able to find this at your local hardware store, but make sure to read all the ingredients carefully to ensure you don’t waste your money.

In addition, make sure you get a selective product that will kill the crabgrass but won’t harm the healthy lawn around it.

And, since crabgrass is an invasive grass, you need a product with extra killing strength for grass, not broad-leaf weeds.

There are two types of chemical treatments you can use: pre-emergent and post-emergent herbicides.

Try looking for these three chemical ingredients in pre-emergent herbicide products:

Dithiopry
Prodaimin
Pendimethalin
Oryzalin (best for warm-season grasses)

Look at the labels closely, as these ingredients can come in different brand names, such as Dimension, Barricade, Scotts Halt and others depending on where you live.

Ask an attendant if you’re unsure which one is the right to buy, as they will most likely be familiar with the best crabgrass preventers for your area.

Pre-emergent weed killer

To really tackle your crabgrass problem head-on, using a pre-emergent herbicide is an effective way to kill crabgrass before it grows.

The granular herbicide will kill generate a chemical barrier at the surface of the soil and prevent the germination cycle from starting.

Apply this in the spring before the crabgrass seeds begin to sprout, ideally after your second mowing.

If your crabgrass problem is bad and widespread, you may need to apply the herbicide several times during the season, as the crabgrass may sprout up again in the summer if you miss dormant seeds.

In addition, the herbicide usually has a lifespan of 50 days post-application (varies by product), so it won’t last the entire season.

Lastly, even if you treat your lawn with pre-emergent weed killer, it won’t matter if your lawn butts up against your neighbor’s, who hasn’t taken care of their crabgrass crop.

One gust of wind will blow thousands of seeds onto your yard, especially if your herbicide is nearing the end of its application and potency life.

To save some time, you can also use a fertilizer that already has crabgrass herbicide in it.

These combination products are fairly inexpensive and a little goes a long way.

To apply, wait until rain is in the weekly forecast and the weather hits around 52 degrees. Then, work the fertilizer into the soil.

This will help thicken the turf and squeeze out small crabgrass plants.

If you’ve decided to take the herbicide route, you’re ready to get applying.

Use a spreader or sprayer and get the whole lawn wet. Concentrate the product around driveways and walkways, where crabgrass is likely to take root.

Avoid spreading the herbicide when rain is expected in the forecast, as this can wash away the chemicals.

Post-emergent weed killer

If crabgrass has already taken hold in your lawn, the pre-emergent herbicide isn’t likely to help.

You’ll need a post-emergent herbicide that will prevent the crabgrass seeds from reaching their full germination cycle and kills the plant itself.

These kinds of herbicides usually come in liquid form and aren’t meant to be spread widely.

They are more of a spot treatment. It’s important to always read product labels carefully, as your grass type may not be listed as approved to treat.

In addition, always read and follow safety instructions to the letter.

These products can be made with flammable chemicals, and while they can be very beneficial in the long run, they also can be dangerous if used incorrectly.

Wear gloves, long-sleeved clothes, and safety goggles as you apply to protect your face and skin.

Hire a professional

Sometimes it’s best to just leave things to an expert and call a professional to help with your crabgrass problem.

After all, you don’t want to create more of a problem than you originally intended by killing healthy grass while getting rid of the crabgrass.

These services can control weeds, build the thickness of your lawn and prevent the next crabgrass cycle from taking root.

In addition, most local services are more familiar with the crabgrass type in your area and will know the best way to treat it.

Maintain a healthy lawn

Perhaps the best and most effective way to keep crabgrass from taking root in the first place, you should aim to maintain a healthy, green lawn throughout the year.

This will keep the weeds at bay when germination season starts.

Dense, regularly watered turf will stop crabgrass seeds from germinating and spreading.

This way, you won’t even need to spend time weeding or applying herbicide because your defenses will already be up.

Here are a couple things you can do to keep your lawn healthy:

1. Mow at the proper height

If you mow at the proper height for your grass type, you’ll discourage crabgrass plants from growing.

Set your mower to one of its top settings so it mows higher (around three inches), allowing taller grass blades to shade the soil.

You can also leave grass clippings behind to add natural nutrients to the soil and prevent the germination of crabgrass seeds.

2. Feed your lawn regularly

If your lawn is thick and lush, weeds (and crabgrass) won’t have much space to grow.

But, if your lawn is unfed and prone to external stress, weeds are more than likely to take root in this dehydrated space.

Feed your lawn regularly (usually every 6 to 8 weeks) during the primary growing season.

This will leave your lawn less suspectable to weeds and crabgrass, leaving little space for them to grow, due to the density of the healthy grass.

3. Give your lawn a good watering

Weeds love adverse growing conditions and can thrive better than most lawn grasses in arid weather.

If your watering is infrequent and shallow, the root growth of your grass will also be shallow.

This will make your grass especially susceptible to weather conditions like heat and drought, leading to thin patches and bare spots.

Crabgrass plants love these spots and will take advantage of them to take root and grow.

To prevent this, water your lawn deeply and regularly, usually at a depth of 6 to 8 inches.

This will encourage your lawn to develop deeper roots and thicker grasses, crowding out pesky weeds.

4. Repair lawn damage.

When frost hits during the colder fall months, crabgrass plants will be killed off.

Although this sounds good, it will leave behind bare spots on your lawn.

Fast-forward to the spring and pesky crabgrass plants will then take root in these bald spots again.

Luckily, you can repair these spots with a patching or grass repair product.

Make sure to regularly water these spots so it can catch up to the dense grass on the rest of your lawn.

Try a few non-conventional ways

Suffocate the crabgrass

To smother the crabgrass and prevent it from getting any sunlight, you can cover the crabgrass with a heavy brick, tile, or other object.

Then, wait 4 to 6 weeks to uncover the object.

Once you remove it, the crabgrass will most likely be smothered to death and easy to remove from the ground.

You can then rake over the ground’s surface and reseed the area to grow desirable turf.

Use gardening vinegar

If you can’t get to a hardware store and need a quick fix, using gardening vinegar is an effective, all-natural method to kill crabgrass.

Luckily, this won’t create any soil damage or impact your healthy grass.

Put the vinegar in a spray bottle (make sure it’s 5% acidity or higher) and spray the vinegar on the crabgrass until it’s completely soaked.

Repeat this process a few times over in the following weeks until the weed is completely dead.

You can then remove it and reseed the area.

Pour boiling water on the crabgrass

Despite being an old-fashioned method, you can kill crabgrass and any other unwanted weeds by pouring hot, boiling water on and around it to get the roots.

Be careful with this method, however; it can kill healthy grasses as well as the pesky crabgrass.

Conclusion on Crabgrass

Overall, a great defense is learning how to spot crabgrass early and often.

Pull crabgrass out as soon as you spot it, which will help prevent even more seeds to spread.

If the crabgrass tuft is young, it will only leave a small hole in your turf, which more mature, desirable grasses will fill in.

If you see light green grass blades thickening up the rest of your lawn, double-check that it’s not young crabgrass beginning to sprout.

Though crabgrass can be difficult to conquer and can take a bit of creative thinking, following these tips will prevent the seeds from germinating, allowing you to win not only the battle, but the war against crabgrass.