Crabgrass is an invasive annual weed that can quickly get out of hand if not properly prevented using crabgrass preventers and pre-emergent herbicides, or killing crabgrass using post-emergent herbicide weed killer. Crabgrass will begin to germinate when the soil temperatures reach approximately 55 degrees for four or more consecutive days and continue to germinate throughout the spring and early summer months as the ground temps approach 70 degrees.
Smooth crabgrass and large crabgrass are the two most popular species of crabgrass in cool-season lawns – particularly in the Northeast. Applying a pre-emergent – such as prodiamine in early spring (April) as soil temperatures are consistently in the low 50s, and a second application, such as dimension in late May as the soil begins to hit the 60s – will help prevent the germination of new crabgrass.
But what happens if you miss an application in controlling crabgrass and need to take action? You need an effective crabgrass killer that will both be safe for your good turfgrass (TTTF, KGB, Ryegrass) but will quickly kill and get rid of crabgrass.
I’ve treated hundreds of acres of lawns using many different post-emergent herbicides. Below is my top-5 list of liquid crabgrass killers for weed-free lawns.
Drive XLR8 Herbicide Crabgrass Killer is one of the highest-rated, best-selling crabgrass herbicides on the market today. It contains over 18% quinclorac as the main active ingredient, undeniably the best herbicide to kill crabgrass – particularly in mature crabgrass plants in over three tiller stages. It is also labeled for many other weeds like white clover, dandelion, Kikuyu grass, and more.
Lawn Phix Review: This water-based formula is easy to work with for crabgrass control and provides quick uptake by the plant. I have a small test plot in my backyard, and Drive (quinclorac) with MSO provided the fastest visual response within five days. Our test of Drive XLR8 only needed one application – even for some mature crabgrass plants of 4+ tillers.
Drive tank mixes well with T-Zone for a fantastic grassy and broadleaf weed-killer combination. Drive is the best option for those looking for professional-grade products and the convenience of simply measuring and mixing. It does not come with a measuring cup so plan accordingly.
- Apply 1.45 fluid ounces of Drive XLR8 per 1,000 square feet
- Do not mow two days before or after applying Drive XLR8
- Do not water or irrigate for 24 hours after application
- Do not apply to fine fescue unless it’s part of a blend
- One-half gallon (64 oz.) covers one acre of established turf
- Labeled for Bermuda Grass, Buffalograss, and Zoysia (warm-season grass type)
- Not labeled for St. Augustine, Centipede grass, or Bahiagrass (warm-season grass type)
Drive is best used when with a Methylated Seed Oil (MSO).
Before and after photos of testing Drive XLR8; images are seven days apart.
Acclaim Extra Selective Herbicide is a post-emergent herbicide for the control of crabgrass and goosegrass in cool-season turf. Acclaim Extra contains the active ingredient Fenoxaprop-p-ethyl.
Acclaim Extra controls all stages of crabgrass. However, unlike many crabgrass killers, Acclaim Extra does the best job on large crabgrass plants at the 4-tiller stage and larger. I’ve used this with great results on Japanese stiltgrass.
The cost per application is less than $0.75 per 1,000, and a quart makes up to 48 gallons of solution. And above all, it’s versatile, and it works. Do My Own now has a “kit” that includes Acclaim Extra, Spreader Sticker, and Blue Dye.
Lawn Phix Review: Another water-based formula that was easy to work with. This systemic product was rapidly absorbed through the foliage of the crabgrass. Our test application of Acclaim was on par with Drive for the larger and mature crabgrass weeds.
The higher price tag upfront makes this #2 on our overall list.
|CRABGRASS GROWTH STAGE||FL. OZ / 1,000 SQ. FT|
|1-2 tiller stage||0.46|
|3-4 tiller stage||0.64|
|4-5 tiller stage||0.90|
- Labeled for Bermuda Grass and Zoysia (warm-season grasses)
- Not labeled for St. Augustine, Centipede grass, Buffalograss, or Bahiagrass (warm-season grasses)
Tenacity Turf Herbicide is also very effective as a post-emergent crabgrass killer, particularly in younger crabgrass in the one-to-three tiller stage, some broadleafs weeds, and other grassy weeds. Bleaching of crabgrass should occur within one week of application. A second application two weeks later may be needed to completely eradicate the crabgrass.
Arguably the most popular and versatile herbicide is Tenacity, by Sygenta. This remarkable product contains Mesotrione as its main active ingredient. Mesotrione is one of the very few herbicides that are safe to apply as a pre-emergent at seeding – it will prevent crabgrass seeds from emerging (up to 4 weeks) but does not affect your good grass seeds from germinating.
You can also use our free Tenacity Calculator to make sure that you get your application right.
Lawn PhixReview: We love how little Tenacity turf herbicide is needed per application. However, measuring with a syringe can get messy, and we recommend wearing gloves, especially with this product. It also took two applications to kill crabgrass completely. The visual bleaching effects weren’t noticeable until about day 5.
Overall, a great versatile herbicide that can be mixed with Speedzone for another great “cocktail” for grassy and broadleaf weeds. It’s also good to have in the event you have crabgrass or need to seed in the spring.
Cons of this product:
- Tenacity turf herbicide can cause temporary bleaching of good turf
- Quinclorac vs. Tenacity: Tenacity is best suited for smaller, younger crabgrass plants. Quinclorac should be used on any crabgrass plants that are larger than the three-tiller stage
- When used as a pre-emergent during seeding, the efficacy will last just approximately 30 days
- Tenacity is best as a post-emergent herbicide when used with a non-ionic surfactant (NIS)
- Mix 1/2 teaspoon of Tenacity with 1.5 teaspoons of NIS per gallon per 1,0000 sq. ft.
- Add 1/2 of your total water to your tank sprayer. Add Tenacity + NIS. Then add the remaining 1/2 of the water
Quinclorac 75 DF is Lawn Phix’s choice for crabgrass killer and crabgrass control. Quali-Pro is a company that makes effective products and weed killers at a very affordable price. The “75” refers to the 75% active ingredient, quinclorac; the “DF” means dry flowable, a dry granular product that is easily mixed and dissolved in water to make a liquid sprayable herbicide.
Lawn Phix Review: The same Active Ingredient (AI) as Drive, Quinclorac worked quickly on the crabgrass. The measuring is more tricky, though. The dry flowable ‘pellets’ need to be accurately measured on a small scale/yield. I was cognizant of keeping shaking the sprayer to keep the chemicals suspended in the tank. Looking at our image above, that was a very large, mature crabgrass plant. This needed two applications on our test, but it did the job.
Overall, Quinclorac 75 DF is the best option for those on a more strict budget and who don’t mind weighing out the solid product and mixing.
Cons of this product:
- The Dry-Flowable needs to be dissolved thoroughly. If not, it may not suspend properly, which may cause the product to spray an inaccurate ratio of active ingredients.
- If not dissolved and broken down properly, pellets may clog the nozzle of the sprayer
You can also buy Quinclorac in 1.5 L liquid, too. A great, affordable option that kills crabgrass exceptionally.
Q4 Plus Turf Herbicide is an excellent crabgrass killer and all-around broad-spectrum weed killer. The manufacturer PBI Gordon Corporation is a very reputable company. They also manufacture popular herbicides such as Speedzone, Surge, and my personal favorite pre-emergent to be used at seeding, Tuperspan.
This 4-way herbicide weed killer contains Quinclorac, Sulfentrazone, 2,4-D (dimethylamine salt), and Dicamba, and is designed to treat crabgrass, yellow nutsedge, and a long list of commonly found broadleaf and grassy weeds. For broadcast and spot treatments of Q4 Plus Turf Herbicide, use 2.6 – 3.0 oz. per gallon (1,000 sq. ft.).
When it comes to a crabgrass killer, you want to ensure you’re buying the right product for your lawn and turf type. Tenacity is a great option, particularly if you plan on using this as a pre-emergent during seeding or overseeding your lawn. But herbicides containing quinclorac may be your best weapon against larger, more mature crabgrass plants.
If you need something that’s more readily available in big box stores and local hardware stores, Ortho Weed B Gon Plus Crabgrass Control is a very popular weed killer. While we have not used this weed killer product, we’ve seen the Ortho Weed B Gone Plus in our local stores in town – some of the staff call it the best crabgrass killer that they carry (contains about 2-3% quinclorac)
We hope this list of post-emergent crabgrass herbicides and weed control was helpful.
Think we missed some? Or want to let others know more about these crabgrass killer products? Feel free to comment below! Be sure to check out our top pre-emergent herbicides / grassy weed preventers and when to apply crabgrass preventer.
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Crabgrass Killer FAQs
What kills crabgrass without killing grass?
When used as directed according to the labels, these 5 crabgrass killers will kill crabgrass of many tiller stages without harming your good turf. Chemicals like Fenoxaprop-p-ethyl (Acclaim) and Quinclorac (Drive XLR8) are very effective. Mesotrione (Tenacity) is effective at killing and preventing crabgrass, but can often temporarily bleach your good grass.
Is crabgrass an annual, biannual, or perennial weed?
Crabgrass is an annual grassy weed and a plant that produces seeds. As crabgrass matures in the summer, it goes to seed and ultimately dies off. The following spring, those seeds germinate when soil temps reach approximately 55 degrees and emerge as young crabgrass.
When should I put down crabgrass killer?
Always follow the manufacturer’s directions on the labels. If you missed the pre-emergent window and see crabgrass in the spring, it’s best to attack the plant while it is in an early tiller stage. You can spray again into the summer but follow the application rates/intervals, maximum dosage, and outside temperature warnings (generally under 80-85 degrees).
Will pre-emergent herbicides kill crabgrass?
Yes and No. When applied early and correctly, crabgrass pre-emergents will help prevent the crabgrass from emerging from the soil (it will also prevent your good grass seed from emerging, too). As the crabgrass seeds begin to germinate in the soil, the pre-emergents will prevent the crabgrass from surviving. However, if crabgrass has germinated and emerged from the soil and is visible on your lawn, then a pre-emergent will not kill the crabgrass plant – a post-emergent crabgrass killer is needed.
Images: Lawn Phix Crabgrass Killer Herbicides
Lawn Phix used crabgrass killer + herbicides