10 Best Post Emergent Crabgrass Killers 2025 in the United States

Ortho WeedClear Lawn Weed Killer Ready-To-Use is designed to tackle crabgrass, dandelion, clover, and other common lawn weeds with a single application. One of its strengths is the included battery-powered Comfort Wand, which helps you target weeds precisely and avoid spraying your grass unnecessarily. It works well on several popular lawn grasses like Bermudagrass, Fescues, and Kentucky Bluegrass, making it a flexible choice for many lawn types. The product is best used in spring or fall when weeds are young and actively growing, which helps improve its effectiveness.

Being ready-to-use in spray form means it’s convenient and doesn’t require mixing, so it is user-friendly for those not comfortable with complicated application steps. It’s not available in some states like Florida and Louisiana, which limits accessibility depending on your location. Some users mention it works quickly to kill weeds down to the root, but as with many herbicides, repeated applications might be needed for stubborn weeds. The 1.1-gallon size is good for spot treatment rather than large lawns.

If you’re looking for a straightforward, targeted weed killer that’s easy to apply and covers multiple weed types, this product is suitable, especially for homeowners wanting to maintain a healthy lawn without complex treatments.

The Ortho GroundClear Weed and Grass Killer is a liquid spray designed to target unwanted weeds like crabgrass, dandelions, chickweed, and moss in patios and landscaped areas, but not on lawns or desirable grass. Its active ingredient, ammonium nonanoate, works quickly—showing results within 15 minutes—and becomes rainproof after drying for about two hours. This means you can rely on it even if the weather changes shortly after application. The product is selective in that it should only be used where you want to kill all vegetation, such as walkways, driveways, and under trees, rather than on healthy grass you want to keep. It's best applied when weeds are small, actively growing, and dry, ensuring effectiveness. A handy Comfort Wand applicator helps you target weeds precisely, reducing waste and accidental damage to nearby plants.

Safety-wise, the product allows people and pets back into the treated area once it has dried, which is convenient for home use. Additionally, it’s OMRI listed, indicating it meets organic standards and has a lower environmental impact compared to some harsher chemicals. However, it’s not suitable for spot-treating individual weeds on lawns, and because it kills all plants it contacts, care must be taken to avoid desirable greenery. Users should also note it has a liquid spray formulation, which requires some handling precautions to avoid overspray.

This product is well suited for homeowners looking to clear tough weeds from hardscapes and landscape beds quickly and safely, especially if they want an organic-friendly option.

The Syngenta Tenacity Herbicide is a versatile liquid weed killer designed for lawns and turf grasses. One of its primary strengths is the active ingredient, Mesotrione, which provides broad-spectrum control over 46 types of weeds and grasses, including crabgrass, goosegrass, and dandelion. This makes it a powerful option for maintaining a healthy lawn.

Its selective pre- and post-emergent control capabilities mean it can target existing weeds while preventing new ones from emerging, and it is safe to use around the time of seeding, which adds to its flexibility. The ease of measurement and application is another plus, as the design of the bottle ensures precise dosing without the need for additional tools.

However, the product’s effectiveness and safety need to be balanced with environmental impact considerations, as it is a chemical herbicide. At 8 ounces, the product covers a significant area but is relatively small in volume, so larger lawns may require multiple purchases.