Top 7 Best Post-Emergent Crabgrass Killers | 2021 Reviews

Controlling crabgrass at home or in an establishment can be a lot of work. The younger ones are easier to kill, but the more mature ones take weeks before you can manage its growth. With the right type of herbicide, the task can become more bearable. 

Assessing items for your gardening needs can be challenging. You need to check their substance, duration, and effectivity. Attention to detail is the most crucial character that you need to have in this activity. If it sounds too much on your plate, you may need a little help on which product to buy. 

You came to the right place if you are new to gardening or searching for new products. We picked the best crabgrass killers to help you improve your lawns and other gardening areas.

Top 7 Best Post-Emergent Crabgrass Killers Reviewed

  1. WeedClear Lawn Weed Killer by Ortho – Best Overall
  2. Speed Zone Lawn Weed Killer by PBI/Gordon’s – Best Value
  3. Weed B Gon Plus Crabgrass Control by Ortho – Editor’s Choice
  4. Surfactant for Herbicides by Southern AG
  5. All-in-One Weed & Feed by BioAdvanced
  6. Halts Crabgrass & Grassy Weed Preventer by Scotts
  7. Ready-to-Use Weed & Grass Killer III with Comfort Wand by RoundUp

#1. WeedClear Lawn Weed Killer by Ortho – Best Overall

Ortho WeedClear Lawn Weed Killer Ready to Spray: For Northern Lawns, 32 oz.

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  • Item Weight: 2 pounds
  • Dimensions: 2.33 x 5.5 x 11.25 inches
  • Area Coverage: Up to 5000 sq. ft.
  • Net Content: 32 oz.
  • Waterproof Duration: 1 Hour

Spring and summer is the favorite time for crabgrasses to grow. They like germinating in bare lawns until it dies in fall. If you leave it untreated, they can grow in a massive amount. The mature ones are more challenging to control, so you have to handle them as early as possible. 

Apart from maintaining your lawns clean and regularly cutting grasses, you also have to use an effective herbicide. One of the top-selling post-emergent crabgrass killers is Ortho’s WeedClear Lawn Weed Killer. Many users find its fast-acting formula effective, and it delivers on what it promises. 

Convenience is what you will get from this Ortho product. It is ready-to-spray and has a wide area coverage of up to 5000 sq. ft. After attaching it to a water hose, you can begin using it on your lawn. It guarantees to kill more than 200 grasses, such as crabgrass, dandelion, and clover. This herbicide targets the weeds’ roots and is effective in a single application. The product is waterproof within an hour, so you do not have to worry if the rain comes your way. 

The best thing about this crabgrass killer is it does not affect your lawn. They remain healthy and keep your Bermuda grass growing. However, you have to follow its instructions well, especially when it comes to temperature. You must apply it during the day with a temperature of fewer than 90 degrees Fahrenheit.

If you are reseeding your lawn, you may not be able to use this weed killer yet. Observe the lawn as weeds start to grow because it is easier to treat them when still young. Bar your children and pets to go outside, too, if you only sprayed this chemical as it may harm their health.

Overall, this weed killer is a force to reckon with because 90% of its users find it effective. The rest still needed to figure out if they are using the item right.

Kills more than 200 types of weeds
May take two or more applications in some lawns
Improves the quality of the lawn
Expensive price
Water-resistant within an hour
Requires a single application
Effective fast-acting formula

#2. Speed Zone Lawn Weed Killer by PBI/Gordon’s – Best Value

Speed Zone Lawn Weed Killer by PBI/Gordon’s

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  • Item Weight: 1 Pound
  • Net Content: 20 oz.
  • Area Coverage: 13,000 to 18,000 sq. ft.
  • Duration of Effectivity: Within one hour

Got a wider lawn? You may be itching to clean that area for years now, and you still could not find any effective weed killers. Speed Zone might be the answer to your prayers without killing your healthy grasses. It has its perks and drawback that you may want to consider.

PBI/Gordon’s Speed Zone Lawn Weed Killer is suitable for lawn areas of up to 18,000 sq. ft. The nice thing about this herbicide is its fast effectivity once you apply it to your lawns. However, it does not have a ready-to-spray capacity. Thus, you need to provide a separate sprayer to disperse the solution evenly. 

You may be surprised when your lawn will look dry and dead after applying it, but you do not have to worry. It only shows that the weeds growing in your backyard are beginning to die. Give it two weeks to reseed, and your lawn will look healthier and cleaner than it was for years. 

Despite its assuring features, you have to follow the temperature guidelines well. Your attention to detail is much needed on this part because it may burn your lawn when you use it in hot weather. It may not remove the weeds 100%, but at least 80% of the job is done. 

You only have to make sure that you keep them away from the lawn for five hours before allowing them to play again. Indeed, PBI/Gordon’s formula is one of the most effective when it comes to larger areas of home yards.

Does not affect grasses that are healthy to the yard
Cannot kill all the weeds in your lawn
Effective within an hour of application
Does not have a ready-to-spray cap
Can kill different types of weeds
Not advisable under a hot weather
Only takes two weeks to reseed
Suitable for larger home lawns

#3. Weed B Gon Plus Crabgrass Control by Ortho – Editor’s Choice

Weed B Gon Plus Crabgrass Control by Ortho

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  • Item Weight: 2.44 pounds
  • Dimensions: 2.33 x 5.5 x 11.25 inches
  • Net Content: 32 oz.
  • Area Coverage: Up to 5000 sq. ft.

Quinclorac is an effective solution for killing crabgrasses. You have to treat the weeds as early as possible to avoid them from spreading. This solution is the main ingredient in Ortho’s Weed B Gon product. While it can free your lawn from more than 200 types of unnecessary greens, the brand crafted it specifically for crabgrasses.

This type of weed is more active in spring and summer because of the higher temperature. It can spread more than 500 seeds, making it less controllable if you leave your yard alone. Like the Ortho’s product that topped our list, Weed B Gon can only cater up to 5000 sq. ft. However, you will see how effective this item is in a week. 

While it promises to have a fast-acting formula, a day may not be enough if you have an excessive amount of crabgrass on your lawn. It is also crucial to note that this formula may not kill all the seeds, but it will prevent them from sprouting the next year again. It would be advisable to pour a more concentrated amount of this herbicide into your lawn during the first time of use. Make sure that the weather is suitable based on the instructions given by the brand. Using it under extremely hot weather may kill the Bermuda grasses and other plants. 

To avoid any disappointments with the product, you shouldn’t set your expectations at a higher level. It may be effective, but it cannot kill the weeds 100%, like the previous items. It would help if you consistently put this chemical on your lawns until you see the results you needed.

Easy to use because of the ready-to-spray capBurns other healthy grasses under an extremely hot weather
Prevents crabgrasses from sprouting again
Does not prevent the germination
Maximum effectivity in one week
Limited area coverage

#4. Surfactant for Herbicides by Southern AG

Surfactant for Herbicides by Southern AG

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  • Item Weight: 1.17 pounds
  • Dimensions: 4.15 x 1.95 x 6 inches
  • Net Content: 1 Pint

Cleaning your lawns and killing the weeds rooting from it should be done with a surfactant. It removes the water’s surface tension and allows the herbicide to penetrate the soil a lot better. The most popular surfactant from Amazon is the product from Southern AG. It is not too expensive, easy to use, and mixes well with any crabgrass-killing formula. 

Surfactants can increase the coverage of an herbicide, making it more effective and speeds up the chemical’s effectivity. You only need to add a teaspoon of this product to your sprayer, and you can apply it directly to the lawn. The herbicide sticks longer to the weed leaves, and the soil absorbs the formula a lot faster. 

What’s more, it can expand the capacity of your herbicide from what it states on its product description. It provides the same effective result or even better. After a few hours, you may notice that the poison ivy and dandelions are starting to wilt. Give it a day or two, and you will see your pesky crabgrasses begin to dry out. 

Another thing that makes this surfactant useful is it is not only limited to soil use. If you have a fishpond filled with algae, put this on your cleaning solution, and you will never worry that algae will grow again. It is quite rare to find a low-cost item that can effectively help you with your gardening needs. 

In less than 14 days, you can begin planting the seeds of your choice on your lawn and see them flourish without any problems caused by the chemicals you used.

Makes herbicides and pesticides more effective
Available items online are samples only
Wider coverage of penetration in your lawn
An add-on to herbicides only
More rapid effectivity of the formula
Formula sticks to leaves longer
Less expensive

#5. All-in-One Weed & Feed by BioAdvanced

All-in-One Weed & Feed by BioAdvanced

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  • Item Weight: 24.2 pounds
  • Area Coverage: Up to 10,000 sq. ft.
  • 25% slow-release formula

The sunny season is coming, and are you ready to face the sprouting weeds in your lawn? If not, then you might want to prepare your gardening essentials because they may keep you busy the whole summer.  BioAdvanced Weed & Feed formula is both a killer and a feeder. Many people love it because it can save your time and money.

The brand’s formula targets two things. It aims to clean your lawn from the unnecessary weeds that make it look dirty and less appealing. You can observe its effect after two to three days from your application. The crabgrass dies, so as the dandelion, clover, and other broadleaf species. More than that, it will not hurt your lawn. Instead, you will feel thankful for it. 

The second goal of BioAdvanced is to keep your yard healthy by supplying the greens with essential nutrients. You do not need to buy two separate chemicals when maintaining your lawn. All you need is this Weed & Feed item that has a Micro-Feed action property. You will see your favorite plants grow healthier because of the fertilizer component that comes with the solution. 

It has a wider coverage, too, of up to 10,000 sq. ft. However, it requires you to add a spreader so that you can reach its maximum capacity. Skipping this solution may result in buying another two bags of the formula. Not all brands offer this all-in-one solution to your lawns. It is the reason why you should not miss this item.

It has a micro-feed action formula for your healthy greens
May need to a spreader to reach the stated coverage
Increases your lawn’s resistant to heat and droughtMore effective in Norther USA lawns
Kills broadleaf, crabgrass, and other grassy weeds
Not budget-friendly
No need for a crabgrass preventer

#6. Halts Crabgrass & Grassy Weed Preventer by Scotts

Halts Crabgrass & Grassy Weed Preventer by Scotts

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  • Item Weight: 9.63 pounds
  • Dimensions: 15 x 10 x 3 inches
  • Area Coverage: 5000 sq. ft.

Scotts is a popular brand when it comes to lawn formula essentials. Its catalog has a set of solutions that is suitable for a specific season. What we are highlighting here is perfect for early spring. It is the perfect time to prevent crabgrass from growing or treating those youngsters. Numerous lawn owners adore Scotts because excellence is what it promises to provide.

The Crabgrass and Grassy Weed Preventer formula makes sure that germination becomes impossible. If your lawn has been suffering from too many weeds in the past years, it is now the right time that you start taking care of it. Moreover, extreme weather and freezing winter will not affect the performance of the chemicals. There is not a day that you will worry about the spreading of the weeds’ seeds. 

If you treat your backyard correctly, there is a lower chance that weeds will get on your way. It would help if you always took note that weeds should be prevented before they sprout again. That is why you must observe keenly if signs of unnecessary greens are surfacing the area. 

Like other brands, you have to apply the formula on the weather that is friendly to it. The worst thing that could happen is it will leave your lawn arid until you can hydrate it again. Patience and the right post-emergent regimen is the key for your lawn to become greener and healthier. The good thing with this product is you do not need to maintain your lawn more than twice a month.

Eliminates seeds and decreases the possibility of sprouting again
Can leave the soil arid when not applied correctly
Perfect for pre-emergent and post-emergent crabgrass
Does not require constant maintenance
Reasonable price with the effectivity
Effective even in extreme weather

#7. Ready-to-Use Weed & Grass Killer III with Comfort Wand by RoundUp

Ready-to-Use Weed & Grass Killer III with Comfort Wand by RoundUp

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  • Item Weight: 12.48 pounds
  • Dimensions: 5.75 x 9.38 x 12.5 inches
  • Net Content: 1.33 Gallons
  • Area Coverage: 400 sq. ft.

Having a smaller garden does not mean you are free from any weeds and unhealthy greens. RoundUp’s Weed & Grass Killer III with Comfort Wand is the most practical crabgrass remover that you will need at home. It is comfortable to use and does not require a lot of mixtures before it becomes effective. 

This solution has a ready-to-use formula. It also has a wand, so you do not need to attach it to a hose because the wand can do spraying for you. No more crawling down in lower areas and any hand fatigue because the wand is small, slim, and long enough to reach any areas in your garden.

While the first six brands are meant to cure a bigger lawn with more complicated needs, this one can be used in protecting your vegetables and fruits away from pests and killing the crabgrass in your area. As you can see, it says that the formula is effective immediately after three hours. However, the brand’s rainproof capacity only lasts for 10 minutes, unlike others with a one-hour formula. 

The strength of this formula may leave your lawn without weeds for the rest of the summer. But then, it does not affect the quality of your healthier plants, so it is a win-win formula for owners of small gardens. You have to make sure that you plant the edible ones after three days from the treatment to ensure that they are harmless. 

It can be more effective if you use it during the hot weather so that the soil and weeds will absorb it quickly.

Prevents seeds to germinate whole summer long
Some items do not spray despite following the guide
Quickly kills useless herbs in your backyard
More effective in sunny weather
Friendly to edible fruits and vegetablesThe wand easily breaks
More suitable for smaller garden areas
Does not kill the nutrients in the lawn

Top Pick – Best Post-Emergent Crab Gras Killer

You now have enough knowledge of what post-emergent crabgrass killer you should buy for your lawns. There are many choices, but it is not difficult to decide because each has its own positive and negative sides. It is highly dependent on the needs of your gardens and backyards.

Our top pick is Ortho’s WeedClear Lawn Weed Killer because it checks all the right spots needed for an effective crabgrass repellant. Firstly, the formula prevents the weeds from germinating and growing again. It also has enough coverage if you have a small to medium lawn. When it comes to the price, it is reasonable enough since it is an effective product. Finally, you will witness the fast-action formula that the brand promised.

If you have a more massive lawn or want to have a two-in-one herbicide and fertilizer, then you might want to check PBI/Gordon’s and Scotts’ solutions. In the end, you have to identify your goal and needs so that you will land on the right brand and chemicals.

Best Post-Emergent Crabgrass Killer Brands


As you can see, we featured products from Ortho because of its popularity among the users. Both the WeedClear and Weed B Gon items garnered positive feedback because they are effectively clearing the lawns from unwanted grasses.

More than that, it leaves the healthier plants fresh and keeps the soil from drying out. However, there is a need to strictly follow its guidelines since too much chemical may harm your garden area. Still, these two are true to its fast-acting formula and waterproof system. They are reliable, and it is rare to find reviews about them saying they are not effective.


PBI/Gordon’s products can be more expensive, but the results of its solution are outstanding. Like Ortho, they give clients a satisfying experience because they keep the weeds out the entire summer or year.

What makes this brand at the edge over others is its area of coverage. A bag of this item can cover up to 18,000 sq. ft. It only takes two weeks before you can reseed the lawn. In no time, you will witness how your backyard becomes greener and healthier.


On the third spot of our recommended brands is BioAdvanced. The reason behind this suggestion is the futuristic approach of the brand to its formula. With its all-in-one item, you do not need to spend more on an herbicide and a fertilizer. You can find it in a single product from BioAdvnanced.

However, it still has more to improve as several feedbacks say that the solution is not as effective as the other brands. It may kill but cannot target a lot of unwanted weeds. In time, this brand may improve its formula, and it would top other companies.

Smart Gardener: Picking the Right Herbicide for Your Garden – Buyer’s Guide

Setting a Clear Goal

No matter what you do, a clear goal will take you to the right places. There are herbicides meant to prevent weeds from growing, while others eliminate them. If you are only beginning in doing your lawn, then you must understand its needs. 

You have to consider if you only need a solution to kill the roots or after the nutrients? There are fertilizers today that can do both tasks. Some need a spreader to enjoy its maximum capacity, while others have a ready-to-use formula already.

Types of Weeds Present in the Area

Knowing the weeds, you are targeting is crucial because herbicides can kill a specific plant only. That is why you must check the labels of your weed killer. You might be spending a few dollars on an item that does not include the grasses you are targeting. 

You may want to enroll in an online class or discuss gardening if you take this activity to the next level. There are local groups that also help homes learn more about cleaning your lawn.

Area Coverage and Amount Needed

To keep your budget in check, you have to know the measurement of your lawn. This way, you will know how much herbicides you will need based on your formula’s net content. There are weed killers with larger area coverage, even if they have the same weight as other brands. 

What’s more, some brands require the use of a spreader or a surfactant to increase the coverage. Measuring your lawn and knowing the amount covered by your chosen herbicide will provide you the right price.


As you reached this part, it may be safe to conclude that you have become smarter about taking care of your lawns. There is no shortcut in clearing it, but you can make the task lighter with the right formula in eliminating weeds. Some even feature the micro-feeding formula of their products.

Thus, you must know what your goals are in clearing up your garden. Crabgrass is only one of the many kinds of grasses that can affect the quality of your lawn. Our research highly recommends Ortho’s WeedClear product because it is practical, effective, and provides fast results.

You must not be afraid if you are only beginning to understand your lawns. What matters is that you have a clear goal in sight, and you are ready to learn more about how to take care of it.

FAQs (Frequently Asked Questions)

How do you know that the crabgrass is dying?

You will know that it is crabgrass because the leaves are shaped like crabs. Once you have sprayed the fertilizer in the affected area, the grass will become reddish and purple. That is an excellent sign that the formula is effective. In a few hours or days, it will slowly turn brown until its texture becomes dry. Once it wilts, you can begin clearing it up and reseed the area.

However, not all seeds can be killed by a solution. That is why you must maintain on spraying it in a year so that the grass will not come again the following spring.

When is the right time that you should use a crabgrass killer?

Crabgrass grows commonly during the spring and summer because of the hot weather. That is why you must spray your lawn with a crabgrass preventer after winter if that is possible. If you see some young crabgrass on your lawn, do not wait until it matures. They are more challenging to kill. As soon as you see them, use the herbicide you have at home or choose from the products in our suggested list. 

Is the crabgrass cycle true?

Yes, the crabgrass lives and dies in the same year. However, it is not something that you must take lightly. The thing with this kind of weed is it produces more than 500 seeds. Once fall and winter end, you will be surprised that the crabgrass amount in your lawn doubles and triples. That is why you must spray it with a preventer or a killer before they begin to sprout. 

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