Crabgrass Control | The 9 Most Effective Killers on the Market

Crabgrass is a summer annual weed mostly found in ornamental landscapes, lawns, and vegetable gardens. Two common species in the United States are the large crabgrass and the smooth crabgrass. Both are fairly easy to manage using chemical controls such as crabgrass killers. 

To know more about how these products work, what their active ingredients are, how to apply them, and other interesting information, read further this article!

Do Crabgrass Killers Work?

Crabgrass killers do work when they are used as directed according to their product label. However, if the crabgrass is stubborn, reapplications may be required.

Types of Crabgrass Killers

• Pre-emergence crabgrass killers are used to prevent the establishment of seeds right before the weeds germinate by inhibiting the growth of the weeds’ shoots, roots, or both. As such, the timing of application is usually done during the early spring season when the crabgrass has just emerged or when it has only a 1-tiller growth. 

• Post-emergence crabgrass killers are usually applied when the weeds are actively growing and have reached a mature size of 5-tillers or more. Weed seedlings should have shown up on the surface of the soil. Treatment is usually done in the fall season. 

What to Consider When Choosing the Best Crabgrass Killer?

• Timing of Application. If you wish to prevent the next generation of crabgrass, you would want to use pre-emergence herbicides. If you want to treat the current infestation of crabgrass, select post-emergence products.

• Product Type. Crabgrass killers are available in liquid or dry formulations. It is up to you to choose which product is more convenient to apply. If you have desirable plants in your lawn, it is recommended to use a dry formulation to avoid spray drift and damaging these plants.

• Lawn Size. Although most herbicides have a long shelf life, it is important to choose the right product depending on the size of your lawn.

Best Crabgrass Killers

Spectracide Weed Stop For Lawns Plus Crabgrass Killer

Active Ingredients: 3.74% 2,4-D, dimethylamine salt, 1.79% quinclorac, 0.43% Dicamba, dimethylamine salt, 0.22% sulfentrazone

Specifications: Not only does this work against crabgrass, but it can also kill over 470 species of weeds and both cool-season and warm-season turfgrass without harming lawns as long as it is used as directed. Results are visible in as fast as 5 hours!

How to Apply:

• Apply in the spring to early summer for the best results when the crabgrass is 3 to 4 inches tall. Apply twice within a 14-day interval for particularly dense infestations.

• Use a pressure sprayer for spot treatment at a rate of 5 fluid ounces diluted in 1 gallon of water per 500 square feet of lawn. For broadcast treatments, apply 6.4 fluid ounces of product per 1,000 square feet of lawn. 

• Avoid watering the area within 24 hours. Do not seed new plants into the area until after 4 weeks from the time of application. 

Product Dimensions: 5” (length) x 2.73” (width) x 11.3” (height), with a weight of 1.07 pounds

Preen Crabgrass Control Lawn

Active Ingredients: 0.19% dithiopyr

Specifications: Can stop crabgrass the entire season and can last up to 4 weeks after application, providing both pre- and post-emergence control of the weed’s population. It also prevents the growth of more than 40 common lawn weeds when applied as directed. 

How to Apply:

• Apply 1.5 pounds to 2.1 pounds per square foot of area using a drop or broadcast spreader during the spring for pre-emergence control of crabgrass. Make sure the plants are at their 3-leaf growth stage. 

• This can also be applied during late summer to early fall using the same rate but a second application must be made in the following spring season to provide a longer control of the crabgrass population.

• Reseeding of treated areas should be done 10 weeks after application.

Product Dimensions: 17” (length) x 5.75” (width) x 11.75” (height), with a weight of 15 pounds

Scotts Turf Builder Halts Crabgrass Preventer

Active Ingredients: 1.71% pendimethalin

Specifications: With a single application during the early spring season, this weed killer can stop and prevent crabgrass all season long. You won’t even have to worry about rain or snow affecting its performance! However, it only works as a pre-emergence control for crabgrass. 

How to Apply:

• Apply during the early spring, around mid-February to mid-March, when the lawn is dry to prevent the germination of crabgrass. 

• For broadcast treatment, spreader settings should be at 2 ¼ while drop spreaders should be at 4 ½. Apply 1.5 pounds of product per acre.

• Avoid planting new seedlings within 4 months or sprigging within 5 months after application. You can only make 2 applications a year, allowing a 2-month interval in between. 

Product Dimensions: 24” (length) x 16” (width) x 4.5” (height), with a weight of 2.2 pounds.

BASF Drive XLR8 Crabgrass Herbicide

Active Ingredients: 18.92% dimethylamine salt of quinclorac

Specifications: This herbicide offers both pre-emergence and post-emergence control against pesky crabgrass and other weeds using its water-based, liquid formulation. One perk this product has is that it doesn’t harm desirable plants within the surroundings of the treated area.

How to Apply:

• Apply product to newly-germinated crabgrass to 1-tiller crabgrass as well as mature, 5-tiller crabgrass for consistent results. You can use a spot treatment by spraying at the center of the weeds. 

• The rate for broadcast application is 0.5 gallons per 1,000 square feet of lawn. For spot applications, the rate should be 1.45 fluid ounces per 1,000 square feet of lawn.

• Avoid irrigating within 24 hours after application. Seeding the treated area before, during, and after the application won’t affect the performance of the herbicide.

Product Dimensions: 6.5” (length) x 3.8” (width) x 8.95” (height), with a weight of 5 pounds.

Syngenta Tenacity Turf Herbicide

Active Ingredients: 40% mesotrione

Specifications: A systemic pre- and post-emergence weed killer if you want a selective control of weeds found in turfgrasses, this product works by inhibiting the photosynthetic abilities of crabgrass when it is absorbed through the roots, leaves, and shoots, effectively killing the weed.

How to Apply:

• For preemergence application, mix 4 to 8 fluid ounces in 30 gallons of water per acre. The crabgrass should not have germinated yet for this to be effective.

• For postemergence applications, apply the same rate but make another application 2 to 3 weeks after the first for adequate weed control. 

• Don’t plant any other crop besides turfgrass species in the lawn for 18 months after the last application. 

Product Dimensions: 2” (length) x 2.5” (width) x 4.5” (height), with a weight of 8 ounces.

Primesource Quinclorac Select Liquid Crabgrass Killer

Active Ingredients: 18.92% Dimethylamine salt of quinclorac

Specifications: This product is a selective, pre- and post-emergence herbicide that can be used to effectively control mature crabgrass infestations. As such, it doesn’t damage any nearby desirable plants and can provide up to 90 days of protection.

How to Apply:

• Apply newly germinated to 1-tiller crabgrass, as well as mature, 5-tiller crabgrass for best results. 

• Mix and agitate a sprayer tank half filled with clean water and 1.45 fluid ounces of product for broadcast applications. This rate can be applied to 1,000 square feet of lawn.

• The product can be applied before, during, and after seeding without any negative effects on its performance. 

Product Dimensions: 8.9” (length) x 6.42” (width) x 3.62” (height), with a weight of 0.01 ounces.

Roundup All-in-One Weed Killer for Lawns

Active Ingredients: 0.257% MCPA, dimethylamine salt, 0.029% Dicamba, dimethylamine salt, 0.118% Quinclorac, 0.015% Sulfentrazone

Specifications: This herbicide comes with an extended wand that makes it more convenient for customers to perform spot treatments of crabgrass. It can also kill over 250 species of weeds and won’t harm the desirable turfgrass found in your lawn. Once applied, it starts working immediately and is rainproof for at least 3 hours. 

How to Apply:

• Remove the wand from the side, then insert the plug at the end of the hose onto the knob opening of the product cap and twist until it clicks. Open the wand and lock it into position, then extend it fully.

• Apply as a pre-emergence control, particularly during the early growth stages of the weed. The product can treat up to 1,330 square feet of lawn.

• After use, make sure the lock on the wand is locked, and the knob is turned off.

• If the crabgrass is particularly stubborn, you may apply a second time after 3 to 4 weeks of the first application. Do not make more than 2 applications a year.

Product Dimensions: 5.5” (length) x 9.5” (width) x 12” (height), with a weight of 0.01 ounces.

Ortho WeedClear Lawn

Active Ingredients: 6.423% 2,4-D, dimethylamine salt, 2.13% quinclorac, 0.60% dimethylamine salt

Specifications: Targeting 200 weed species, including crabgrass, this fast-acting weed killer concentrate becomes rainproof within just one hour and kills weeds down to their roots. It is also guaranteed to not harm any desirable turfgrass on your lawn. 

How to Apply:

• Apply when the weeds are actively growing and young. Use 2.5 fluid ounces of product per gallon of water for every 400 square feet of lawn.

• Keep people and pets out of the treated area until it has completely dried. Avoid watering for up to 24 hours after application. For stubborn weeds, perform spot treatments after 21 days. 

Product Dimensions: 2.54” (length) x 4.76” (width) x 11.56” (height), with a weight of 2 pounds.

GORDON’S Trimec Ready Spray Lawn Weed Killer

Active Ingredients: 6.42% 2,4-D, dimethylamine salt, 2.14% quinclorac, 0.60% Dicamba, dimethylamine salt 

Specifications: This crabgrass killer is formulated with a 3-way herbicide blend and can provide pre-emergence control for more than 200 common broadleaf weeds. It can only be used for residential lawns. 

How to Apply:

• Apply in the spring season, when the crabgrass has recently emerged, or when it has grown 3 to 4 inches in height.

• Use a hose-end sprayer, pump-up sprayer, or tow-behind sprayer when applying.

• For spot treatments, mix 2.5 fluid ounces of product into 1 gallon of water to treat 400 square feet of lawn. For broadcast treatment, mix 6.4 fluid ounces in half to 1 gallon of water to treat 1,000 square feet of lawn. 

• If the infestation is severe, reapply the area at the same rate after 21 days.

Product Dimensions: 4.44” (length) x 7.07” (width) x 11.52” (height), with a weight of 2.1 pounds.

List of Sources

Crabgrass – https://ipm.ucanr.edu/PMG/PESTNOTES/pn7456.html

Lectures 5 & 6: Preemergence Herbicides – https://weeds.ces.ncsu.edu/weeds-teaching/landscape-weed-management/preemergence-herbicides/

Postemergent Herbicides for Use in Ornamentals – https://edis.ifas.ufl.edu/publication/WG059

Biology and Management of Crabgrass – https://ag.umass.edu/turf/fact-sheets/biology-management-of-crabgrass