Choosing the right pre-emergent for St. Augustine grass helps prevent crabgrass and other common lawn weeds without harming the turf. This guide reviews five effective products, focusing on coverage, suitability for St. Augustine and centipede grasses, and practical application notes. Each product is evaluated for early spring and fall use, longevity, and any weed-spectrum limitations. Use the buying guide to compare active ingredients, application windows, and safety considerations for your lawn care routine.
| Product | Brand | Key Benefit | Coverage |
|---|---|---|---|
| Southern Ag 006130 Atrazine St. Augustine Weed Killer | Southern Ag | Controls broadleaf and grassy weeds in St. Augustine and centipede | Treats 3,720 sq ft per quart |
| Fertilome (13915) St. Augustine Weed & Feed | ferti-lome | Pre-emergent weed control with a 15-0-4 fertilizer mix | 12.8 lbs per package |
| Scotts WeedEx Prevent with Halts | Scotts | Season-long crabgrass prevention | 5,000 sq ft |
| The Andersons Barricade | The Andersons | Professional-grade pre-emergent for early spring and fall | £ up to 5,800 sq ft |
| Southern Ag Atrazine St. Augustine Grass Weed Killer | Southern Ag | Broadweed control and suppression in St. Augustine and centipede | 1 gallon |
Southern Ag Atrazine St. Augustine Weed Killer, 32oz
Brand: Southern Ag. Size: 32 oz per bottle, treats up to 3,720 sq ft. This product is designed to target a broad spectrum of weeds in St. Augustine and centipede grasses, with emphasis on early-season weed suppression. It is a convenient option for homeowners seeking a reliable pre-emergent that fits standard lawn dimensions. Application guidance suggests uniform coverage to avoid untreated patches. The active ingredient atrazine provides post-emergent flexibility in some climates, but this product is best used as a preventive measure when soil temperatures rise in spring. Consider compatibility with your lawn’s maintenance schedule and other herbicides in rotation.
Fertilome 13915 St. Augustine Weed & Feed
Brand: ferti-lome. Product: 12.8 lb bag. This product combines a pre-emergent with a fertilizer mix, designed for Centipede, Zoysia, and St. Augustine lawns. It provides a 15-0-4 nutrient ratio, promoting lawn growth while suppressing weed establishment. It is not suitable for Bermuda or other northern grasses. When applying, ensure the units align with your lawn size and reapply per label directions after seasonal weather changes. Use caution on newly seeded or stressed turf and avoid overlapping applications with incompatible products.
Scotts WeedEx Prevent with Halts
Brand: Scotts. Coverage: 5,000 sq ft. This product aims to prevent crabgrass and other grassy weeds all season long. It works best when applied in early spring for season-long prevention and can also be used in fall to deter winter weeds like Poa annua. The formulation is designed for active lawn management with easy integration into lawn care schedules, making it suitable for homeowners who want a straightforward preventive option without frequent reapplications.
The Andersons Barricade Professional-Grade Pre-Emergent
Brand: The Andersons. Coverage: Up to 5,800 sq ft. Barricade Pro is a granular pre-emergent designed for professional-grade weed control with early spring and fall applications. It contains prodiamine (0.48%), which targets both grassy and broadleaf weeds, including crabgrass, Poa annua, goosegrass, henbit, and more. It is intended for established lawns, sod nurseries, and landscape plantings. Application should follow label directions precisely to avoid turf injury and ensure effective weed suppression across seasons.
Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon
Brand: Southern Ag. Volume: 1 gallon. This product provides broad weed suppression suitable for St. Augustine and centipede grasses, with a focus on broadleaf weed kill and crabgrass suppression. It complements a preventative lawn care plan by expanding weed-control options across different turf environments. As with other atrazine-based products, follow label directions for safe usage and compatibility with other lawn care chemicals.
Buying Guide
Active ingredients matter for weed spectrum and turf safety. Atrazine-based products are widely used for St. Augustine lawns but require careful application to avoid runoff and over-application. Pre-emergents like prodiamine (Barricade) target a broad range of grassy and some broadleaf weeds, helping cover both spring and fall weed pressures. Mesotrione provides both pre- and post-emergent activity, though it may require moisture for activation and slower visible results. Consider the weed problems in your yard when selecting an product.
Coverage and application zones matter for cost-effectiveness. Smaller lawns benefit from products with clear coverage per unit, such as 3,720 sq ft per quart, while larger properties may benefit from broader coverage options like 5,000–5,800 sq ft per bag. Ensure you select a product that matches your lawn size and seasonal treatment schedule.
Target grasses influence product choice. Some formulas are designed specifically for St. Augustine or centipede grasses, while others are suitable for multiple warm-season grasses. Always verify label guidance for your specific grass type to prevent turf injury or ineffective weed control.
Season timing is critical. Early spring and fall are common windows for pre-emergent applications. Some products work best when soil temperatures rise, while others provide season-long prevention with repeated applications. Align treatment with local climate patterns and typical weed emergence cycles in your region.
Safety and compatibility considerations include avoiding applications on stressed or recently seeded lawns and avoiding mix-and-match conflicts with other herbicides, fertilizers, or fungicides. Always read the label for mixing instructions, watering requirements to activate the herbicide, and any restrictions related to irrigation or rainfall within 24–72 hours after application.
Ease of use matters for homeowners. Granular formulations (like Barricade) may require water to activate, while liquid concentrates ( Atrazine-based products) may depend on spray equipment and proper dilution. Choose a format that aligns with your typical lawn care routine and equipment availability.
Environmental and regulatory considerations include local regulations on atrazine use and any restrictions for certain regions or grasses. Review local guidelines and product labels to ensure compliance and minimize environmental impact.
In practice, the five reviewed products provide a spectrum of options for St. Augustine lawn care. Users seeking a dedicated pre-emergent with strong grass weed control may favor Barricade for professional-grade coverage, while those needing a simpler preventive solution may opt for Scotts WeedEx Prevent or the Southern Ag Atrazine-based products. The Fertilome Weed & Feed option blends weed control with nutrition, suitable for lawns requiring both weed suppression and fertilizer supplementation, but verify grass compatibility before use. Always follow label directions for safe and effective results.