The best crabgrass killers for St. Augustine grass are products that target crabgrass without harming your warm-season lawn. This guide highlights five products well-suited for St. Augustine and Centipede lawns, focusing on user intent, effectiveness, and practical application. Choose based on whether you need post-emergent control, pre-emergent prevention, or a combination approach. The top picks below are organized to help homeowners, professionals, and DIY enthusiasts compare quickly. A quick summary table follows to aid in fast decision-making.
| Product | Best For | Form | Notes |
|---|---|---|---|
| Southern Ag 006130 Atrazine St. Augustine Weed Killer | St. Augustine and Centipede lawns needing quick post-emergent control | Liquid concentrate | Treats up to 3,720 sq ft |
| BASF Drive XLR8 Crabgrass Killer | Broad lawn weed control with residual effect | Liquid concentrate | Up to 30 days residual |
| Southern Ag Atrazine St. Augustine Grass Weed Killer | St. Augustine and nearby turf types needing suppression of crabgrass | Liquid concentrate | 1 gallon size |
| Ortho WeedClear Lawn Weed Killer Ready-To-Spray | Hose-end convenience for quick spot-to-lawn treatment | Ready-to-spray | Kills crabgrass and other listed weeds |
| Agralawn Crabgrass Killer | St. Augustine, Bermuda, Bahia, and Centipede grasses | Granular/foliar?> | Post-emergent root-and-leaf action |
Buyers should consider lawn size, weed timing (post vs. pre-emergent), application method, and local regulations when choosing a product. The table above highlights where each option fits best for St. Augustine grass and related warm-season turf. All products listed are intended for outdoor lawn use and are not substitutes for professional advice in unusual lawn conditions.
Southern Ag 006130 Atrazine St. Augustine Weed Killer 32oz
Best for: St. Augustine and Centipede grasses needing post-emergent control. This product is a quart-sized weed killer designed to treat large areas, with the ability to handle common lawn weeds including those affecting St. Augustine. Selection reason: reliable post-emergent performance in warm-season lawns.
Why chosen: The formulation targets broad broadleaf weeds in St. Augustine grass, helping maintain a clean lawn with fewer surface weeds. Best for homeowners seeking straightforward, spray-ready results in sunny lawns.
Caution: Follow label directions to avoid damage to desirable grasses and to minimize runoff. Do not exceed recommended application rates.
BASF Drive XLR8 Crabgrass Killer for Lawn & Turf
Best for: Lawns needing broad-spectrum control with a residual effect. This post-emergent crabgrass killer targets a wide range of grasses and broadleaf weeds, with a fast-acting formulation. Selection reason: extended residual control helps reduce frequent reapplications.
Why chosen: The product’s water-based formulation supports faster uptake and better performance in varied weather. Good for larger properties where ongoing weed pressure is expected.
Caution: Residual effects mean careful timing to avoid stressing newly seeded or newly sodded areas. Read the label for application windows around heat and rain events.
Southern Ag Atrazine St. Augustine Grass Weed Killer
Best for: St. Augustine lawns needing crabgrass suppression and broadleaf weed control. This one-gallon solution provides extended coverage per application. Selection reason: effective for larger areas with St. Augustine grass.
Why chosen: Atrazine-based products are a common choice for St. Augustine turf when dealing with crabgrass and similar weeds. They can be used as a preventative or post-emergent measure depending on timing and label guidance.
Caution: Atrazine products require careful use around ornamental plants and water sources. Follow label rates and prevent over-application to avoid lawn stress.
Ortho WeedClear Lawn Weed Killer Ready-To-Spray
Best for: Quick, hose-end application for homeowners with limited time or space. The Ready-To-Spray bottle covers up to 5,000 sq. ft. and targets crabgrass along with other listed lawn weeds. Selection reason: convenience and fast results in a single application.
Why chosen: Hose-end application reduces setup time and helps you treat larger patches efficiently. Ideal for homeowners who want simple, home-based weed control without mixing concentrates.
Caution: Not all crabgrass varieties respond uniformly; re-treatment may be necessary if weed pressure persists after the first application.
Agralawn Crabgrass Killer
Best for: St. Augustine, Bermuda, Bahia, and Centipede grasses requiring selective post-emergent weed control. This formula is designed to be leaf-and-root absorbing, with minimal harm to listed turf types when used properly. Selection reason: specifically mentions compatibility with several warm-season grasses found in southern lawns.
Why chosen: It supports post-emergent control while respecting the lawn’s stress tolerance. Useful for those dealing with persistent crabgrass alongside other common warm-season weeds.
Caution: Avoid applying during extreme heat or drought stress, as this can increase turf sensitivity. Always follow label instructions for safe use around desirable grasses.
Buying Guide
What to consider before buying a crabgrass killer for St. Augustine grass:
- Post-emergent vs pre-emergent: Post-emergent products control existing weeds; pre-emergents prevent new crabgrass germination. Your lawn’s current weed stage determines best choice.
- Target weeds: Confirm the product’s listed weeds include crabgrass and common lawn weeds in your region. For St. Augustine, select formulas proven safe for warm-season grasses.
- Application method: Hose-end sprays and ready-to-use bottles offer convenience; concentrates require mixing. Choose based on space, desired deployment speed, and DIY comfort.
- Lawn size and coverage: Compare square footage coverage to avoid under- or over-application. Larger properties benefit from concentrates with higher coverage per bottle.
- Safety and compatibility: Check compatibility with your lawn type (St. Augustine, Centipede) and avoid applying near ornamentals, water sources, or edible plants unless labeled safe.
- Weather and timing: Apply when weeds are actively growing and avoid extreme heat, drought, or rain-precipitation windows that could wash away or dilute the product.
FAQ
- What is the best treatment for crabgrass on St. Augustine grass? A post-emergent crabgrass killer that is labeled for St. Augustine and Centipede grasses is typically most effective, followed by a pre-emergent plan for ongoing protection.
- Can I use atrazine products on my St. Augustine lawn? Atrazine-based products are commonly used for warm-season lawns like St. Augustine, but always follow the label, local regulations, and safety guidelines.
- How often should I apply crabgrass killer? Depending on the product and weather, applications may be needed every few weeks to months. Read the label for recommended intervals and avoid over-application.
- Is a ready-to-spray product better than a concentrate? Ready-to-spray is convenient for smaller lawns or quick spot treatments; concentrates require mixing but can offer greater coverage and cost efficiency per area.
- Will these products harm my St. Augustine lawn? When used as directed on the label for warm-season grasses, these products target crabgrass and related weeds without harming healthy St. Augustine grass. Always test a small area first if you’re unsure.
- Do I need to water after application? Many products do not require immediate irrigation, but following label guidance helps maximize uptake and effectiveness.