Managing crabgrass on St. Augustine lawns requires products that can either prevent germination or kill established weeds without harming the grass. The following selections are designed for St. Augustine, centipede, or nearby warm-season grasses, offering post-emerge control, pre-emergent protection, or a combination approach. This guide compares effective options, application considerations, and how each product fits a typical lawn care routine.
| Product | Use Type | Coverage | Form |
|---|---|---|---|
| Southern Ag Atrazine St. Augustine Weed Killer | Post-emergent weed control | 3,720 sq ft per quart | Liquid concentrate |
| Crabgrass Killer (2 lb) | Post-emergent weed killer | DIY coverage by area | Granular powder |
| Scotts WeedEx Prevent with Halts | Pre-emergent crabgrass prevention | Up to 5,000 sq ft | Granular |
| Prime Source Celsius WG | Post-emerge weed control | Package provided | Water-dsolvable packet |
| Scotts Turf Builder Halts Crabgrass Preventer | Pre-emergent crabgrass prevention | Up to 5,000 sq ft | Granular |
Southern Ag Atrazine St. Augustine Weed Killer
Southern Ag 006130 Atrazine St. Augustine Weed Killer is a specialty herbicide designed to control broadleaf and grassy weeds in St. Augustine and centipede grasses. The product is sold as a quart, with a label indicating it treats up to about 3,720 square feet. Applications are typically suited for post-emergent weed management in warm-season lawns, where selective control is needed without impacting the desirable grass. Homeowners should follow label directions for mixing, timing, and safety precautions, especially when applying near desirable turf or non-target plants. This option is a practical choice for spot treatments around problem areas rather than blanket spraying a large lawn area.
Key considerations: verify compatibility with your specific St. Augustine cultivar, observe weather conditions to avoid runoff, and ensure proper protective equipment is used during mixing and application. For best results, target visible crabgrass and other weeds while avoiding active turf stress periods.
Crabgrass Killer (2, Pounds)
This Crabgrass Killer is presented as a post-emergent treatment designed for St. Augustine, common Bermuda, Bahia, and centipede grasses. It’s advertised to be taken up through the leaves to wipe out weeds and their roots, with minimal harm to St. Augustine when used correctly. The 2-pound format is convenient for treating localized patches rather than broad lawn applications. Homeowners should apply when crabgrass is actively growing and follow label directions regarding coverage, rates, and re-entry intervals after application.
Scotts WeedEx Prevent with Halts
Scotts WeedEx Prevent with Halts is a pre-emergent solution designed to stop crabgrass before it starts, covering up to 5,000 square feet per bag. It emphasizes season-long prevention with the Halts component, which helps reduce the establishment of multiple grassy weeds. For best results, apply in early spring before soil temperatures rise and weeds begin germination. It can also be used in fall as part of a yearly weed-prevention plan to curb winter weeds like Poa annua and chickweed. This product is useful for proactive lawn care rather than post-emergent rescue of already-formed crabgrass.
Prime Source Celsius WG – 0.226 oz Easy Mix Packet
Prime Source Celsius WG comes in an easy mix packet format, designed for post-emergent weed control. The product is promoted as professional-grade with fast-acting results, suitable for golf course quality standards. While marketed for broader application, it can be effective against crabgrass and other common lawn weeds when applied according to label directions. The ready-to-mix packet minimizes measurement steps and helps ensure accurate dosing for targeted treatments rather than oversized applications.
Scotts Turf Builder Halts Crabgrass Preventer with Lawn Food
Scotts Turf Builder Halts Crabgrass Preventer combines pre-emergent control with lawn fertilizer to promote a fast green-up after winter. It stops crabgrass and a range of listed weeds before they invade, making it a convenient option for homeowners who want both weed prevention and turf nourishment in a single product. Apply to a dry lawn in early spring before soil temperatures rise into the 80s for best results, and reapply as directed to maintain season-long protection. This product can be part of a regular lawn maintenance program to minimize annual crabgrass outbreaks.
Buying Guide: Key Purchase Considerations
- Weed life cycle: If crabgrass is already present, choose post-emergent products (e.g., atrazine-based or post-emerge formulas). For preventive care, select a pre-emergent like WeedEx or Halts to curb germination.
- Lawn type compatibility: Ensure the product is labeled for St. Augustine or centipede grasses. Some products are generic or turf-friendly but may stress sensitive grass varieties.
- Application timing: Pre-emergents work best when applied before soil temperatures reach germination thresholds. Post-emergents are applied once weeds are visible and actively growing.
- Coverage and patch treatment: If you have large lawns, prioritize products with larger square-footage coverage. For patchy lawns, spot treatments with post-emergents may be more efficient.
- Safety and re-entry intervals: Follow label instructions for prohibited re-entry times and required protective gear, especially in warmer climates.
- Combination products: Some options offer both weed prevention and lawn nourishment. Consider your soil fertility needs and existing lawn health when selecting.
- Environmental impact: Opt for products with label guidance on non-target plant safety and runoff reduction, particularly near borders, flower beds, or edible landscaping.
In practice, combining a pre-emergent in early spring with a targeted post-emergent treatment can provide robust crabgrass control on St. Augustine lawns. Select products based on your lawn’s current weeds, seasonal timing, and compatibility with your grass variety to achieve the best results while maintaining turf health.