Best Weed Control for St. Augustine Grass
St. Augustine lawns in American yards require targeted weed control that protects the turf while eliminating broadleaf and grassy invaders. The following five products are commonly used by homeowners and lawn-care pros to manage weeds in St. Augustine and Centipede grasses. This guide highlights selective herbicides and weed-and-feed blends, with practical notes on coverage, usage, and safety. Use the buying guide to pick a product that matches your lawn’s needs and climate. The table below provides a quick snapshot of the selected options.
| Product | Brand | Coverage | Type |
|---|---|---|---|
| Southern Ag Atrazine St Augustine 32oz | Southern Ag | 3,720 sq ft per quart | Atrazine Weed Killer |
| Southern Ag Atrazine St Augustine Grass Weed Killer 1 Gal | Southern Ag | Not specified | Atrazine Weed Killer |
| Fertilome St Augustine Weed & Feed 15-0-4 | Ferti-Lome | Not specified | Weed & Feed (Pre/Post Emergent) |
| Spectracide Weed Stop For St Augustine Lawns | Spectracide | Not specified | Weed Stop Concentrate |
| Lesco 50 Lb St Augustine Weed & Feed With Penoxsulam | Lesco | 13,000 sq ft | Weed & Feed (Penoxsulam) |
Southern Ag Atrazine St Augustine 32oz Weed Killer
The Southern Ag 32-ounce Atrazine St Augustine Weed Killer is a focused option for controlling weeds in St. Augustine and Centipede grasses. The label indicates it treats up to 3,720 square feet per quart, making it suitable for mid-sized lawns. Atrazine-based products are well-regarded for broadleaf weed control in warm-season grasses, and this formulation is designed to minimize turf damage when applied according to label directions. It is commonly used in home landscapes where weed pressure is steady and the lawn has established St. Augustine turf. Always follow the label for application timing, rates, and safety precautions to protect nearby plants and water sources.
- Coverage: 3,720 sq ft per quart
- Targets weeds in St. Augustine and Centipede grasses
- Package weight: about 1.02 kg
When applying, ensure weeds are actively growing and avoid mowing or irrigation activities that could dilute the product immediately after treatment. Store in a cool, dry place away from children and pets. Read the full label for any regional restrictions or environmental cautions before use.
Southern Ag Atrazine St Augustine Grass Weed Killer 1 Gal
This 1-gallon atrazine formulation from Southern Ag provides broadleaf weed control compatibility with St. Augustine and Centipede grasses. The product description notes effectiveness on many broadleaf weeds and notes its use in centipede grass as well. It also provides suppression of crabgrass, offering a two-pronged approach against common lawn invaders. For best results, apply when weeds are actively growing and follow label instructions for mixing, rates, and timing. This option is practical for larger lawns or longer treatment intervals between applications.
- Kills many broadleaf weeds
- Also used in centipede grass
- Provides suppression of crabgrass
As with any herbicide, avoid drift to ornamentals or nearby water sources. Wear protective clothing and wash hands after handling. Review local regulations regarding atrazine products in your area, as usage can be restricted in some regions.
Fertilome St Augustine Weed & Feed 15-0-4
Ferti-Lome’s St. Augustine Weed & Feed combines weed control with a 15-0-4 fertilizer mix in a 12.8-pound bag. The product is described as both a pre-emergent and post-emergent herbicide, designed specifically for Centipede, Zoysia, and St. Augustine lawns. It is not recommended for Bermuda grass or other Northern grass varieties. This blend can simplify lawn care by delivering nutrients while targeting young weed shoots and established invaders. For best results, follow the label’s timing guidance relative to your local climate and seasonal weed cycles.
- Pre-emergent and post-emergent weed control
- 15-0-4 fertilizer mix
- Designed for Centipede, Zoysia, and St. Augustine lawns
Always verify compatibility with your specific St. Augustine cultivar and avoid applying on lawns outside labeled grass types. Since this product includes fertilizer, it’s important to monitor for signs of fertilizer burn and water appropriately after application.
Spectracide Weed Stop For St Augustine Lawns
Spectracide Weed Stop For Lawns is formulated for St. Augustine and centipede lawns, available as a ready-to-spray concentrate. The product is designed to kill listed weeds without harming the lawn itself when used as directed, and it includes atrazine to enhance broadleaf and some grassy weed control in St. Augustine varieties. This option is practical for homeowners seeking a ready-to-use spray that targets weed seedlings and established weeds alike, with the convenience of a six-pack in this formulation. Always follow label directions regarding mixing, application rates, and safety precautions.
- Kills weeds, not the lawn, when used as directed
- Contains atrazine for effective control in St. Augustine and centipede lawns
- Ready-to-spray, 32-ounce bottles; six-pack
Consider local regulations and water runoff considerations, especially in areas near water sources. This product is most effective when weeds are actively growing and can be paired with proper mowing and irrigation practices.
Lesco 50 Lb St Augustine Weed & Feed With Penoxsulam
Lesco’s 50-pound weed-and-feed product is tailored for St. Augustine turf with Penoxsulam as the active herbicide component. The package is designed for coverage of up to about 13,000 square feet, and it includes a slow-release fertilizer blend (17-0-17 with additional coated sulfur-coated urea) to provide extended feeding. The label notes that the product should be applied when the turf is wet, and that it will dry to begin delivering results within about two weeks. It’s described as safe for Floratam varieties and provides up to eight weeks of feeding with slow-release action. This option is suitable for homeowners seeking both weed control and turf nourishment in one step.
- Coverage: about 13,000 sq ft
- Penoxsulam herbicide with slow-release fertilizer
- Safe for Floratam variety; designed for St. Augustine grass
- Apply to wet turf; results typically visible within two weeks
As with any weed-and-feed product, monitor for fertilizer burn and follow label directions for timing, weather, and irrigation. This option is best when you want a combined approach to weed control and lawn nutrition in a single application.
Buying Guide
Choosing the right weed-control product for St. Augustine grass depends on weed type, lawn size, and whether you want fertilizer included. The following considerations help compare options and align choices with your lawn’s needs.
Key purchase considerations
- Weed types targeted: Broadleaf weeds, crabgrass, and other grasses respond differently to herbicides. Atrazine-based products are common for broadleaf weed control in warm-season grasses, while Penoxsulam-based blends also deliver targeted control alongside fertilization.
- Grass compatibility: Ensure the product is labeled for St. Augustine or Centipede grasses. Some formulas are restricted to Floratam or specific St. Augustine varieties; avoid products not labeled for your lawn.
- Formulation and application method: Granular weed killers and weed-and-feed blends require different application equipment and timing compared to liquid sprays. Ready-to-use sprays can be convenient for homeowners, while granules may be preferred for larger areas and slower-release feeding.
- Coverage and bag size: Match product coverage to your lawn size. Weed-and-feed blends add fertilizer, which affects feeding schedules and irrigation needs.
- Timing and seasonality: Pre-emergent options are most effective before weed germination, while post-emergent products target actively growing weeds. Weather and recent rainfall influence efficacy and label instructions.
- Safety and environmental considerations: Atrazine and other selective herbicides may have regional restrictions. Always read the label, follow disposal guidelines, and consider environmentally sensitive areas such as near wells or streams.
- Long-term lawn health: Weigh the benefits of immediate weed control against potential turf stress. Slow-release fertilizers help reduce burn risk and extend feeding between applications.
Product-specific guidance
- For smaller lawns, concentrated atrazine products (like the 32 oz option) offer precise, spot-targeted control with clear coverage rates.
- For larger areas, weed-and-feed options can simplify care with concurrent weed control and fertilization, but monitor for fertilizer load and irrigation needs.
- If crabgrass suppression is a priority, look for products that advertise crabgrass control and verify compatibility with Centipede and St. Augustine grasses.
- When in doubt, stagger applications and combine with proper mowing height, irrigation, and seasonal timing to maximize turf resilience.
Across these choices, the best option depends on your lawn’s weed pressure, size, and whether you prefer a stand-alone herbicide or a weed-and-feed solution. Always follow label directions, consider local guidelines, and tailor timing to your region’s climate for the healthiest St. Augustine lawn possible.