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 herbicides. 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 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 soil temperatures begin 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. Here is a list of the Top-5 liquid herbicide crabgrass killers.
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, which is undeniably the best herbicide to kill crabgrass – particularly in mature crabgrass plants in more than three tiller stages.
- Apply 1 .45 fluid ounces of Drive XLR8 per 1,000 square feet
- Do not mow 2 days before or after applying Drive XLR8
- Do not 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
Drive is best used when with a Methylated Seed Oil (MSO).
Acclaim Extra Selective Herbicide is a post-emergent herbicide for 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 a lot of crabgrass killers, Acclaim Extra does the best job on large crabgrass plants at the 4-tiller stage and larger.
While this $82 price tag may seem steep, Lawn Pro has the lowest prices around (on all of these products!) and FREE SHIPPING! The cost per application (0.30 – 0.90 oz./1,000 sq. ft.) is only $0.19 – $0.58 per 1,000. And above all, it works.
|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|
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. Tenacity is also very effective as a post-emergent crabgrass killer, particularly in younger crabgrass in the one-to-three tiller stage. Bleaching of crabgrass should occur within one week of application. A second application two weeks later may be needed to completely eradicate the crabgrass.
You can also use our free Tenacity Calculator to make sure that you get your application right.
- 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
Downfalls to this product:
- Tenacity can cause temporary bleaching of good turf
- Tenacity is best suited for smaller, younger crabgrass plants. Quinclorac should be use 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
Quinclorac 75 DF is Lawn Phix’s choice for crabgrass killers. Quali-Pro is a company that makes effective products at a very affordable price. The “75” refers to the 75% active ingredient, quinclorac; the “DF” means dry flowable which is a dry granular product that is easily mixed and dissolved in water to make a liquid sprayable herbicide.
Downfalls to 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.
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 contains Quinclorac, Sulfentrazone, 2,4-D, 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 crabgrass killers, you want to make sure 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. We hope this list of post-emergent crabgrass herbicides was helpful. Think we missed some? Or want to let others know more about one of these crabgrass killers? Feel free to comment below!
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Crabgrass Killers FAQs
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 and Quinclorac are very effective. Mesotrione (Tenacity) is effective at killing and preventing crabgrass, but can often temporarily bleach your good grass.
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.
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).
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 in your lawn, then a pre-emergent will not kill the crabgrass plant – a post-emergent crabgrass killer is needed.