Direct answer: For St. Augustine grass, choose a liquid weed and feed that fights broadleaf weeds while feeding the lawn, with a formulation suitable for warm-season grasses. The top picks below are chosen for effectiveness against common St. Augustine weeds, ease of application, and suitability for this grass type. Best buyers are homeowners seeking simple, compatible lawn care without complex mixing. The table below compares five strong options at a glance.
| Product | Nitrogen / Weed Control | Best For | Limitations |
|---|---|---|---|
| Spectracide Weed & Feed 20-0-0 (3 Count) | 20% Nitrogen; broadleaf weed control | Weeds in St. Augustine; easy ready-to-use sprayer | May require reapplication for heavy weed pressure |
| Scotts Liquid Turf Builder with Plus 2 Weed Control | Nitrogen boost + broadleaf weed control | General lawn boost with weed control | Hose-end applicator setup required |
| Southern Ag Atrazine St. Augustine Weed Killer (32 oz) | Specialized herbicide for St. Augustine | St. Augustine and centipede grasses | Atrazine usage considerations per label |
| Ortho WeedClear Weed Killer for Lawns Ready-To-Spray | Kills broadleaf weeds; lawn safe when directed | Immediate weed knockdown with hose-end spray | Requires application when weeds are actively growing |
| Bonide Liquid Weed & Feed 20-0-0 (32 oz) | 20% Nitrogen; kills numerous common weeds | Outdoor lawns and garden use | Outdoor-only use; follow label directions |
Note: The table offers a compact snapshot. Details are discussed in each product section to help you compare quickly and choose confidently.
Spectracide Weed & Feed 20-0-0
Brand: Spectracide
Features: Dual-action formula kills weeds while feeding your lawn; targets major broadleaf weeds like dandelion, chickweed, knotweed, plantain, clover, mallow, purslane. Formulated with 20% nitrogen to feed the lawn.
Best for: Homeowners who want a simple, ready-to-use solution to reduce broadleaf weeds in St. Augustine grass while delivering lawn fertilizer in one step. This product is well suited for smaller lawns or areas where a quick, no-muss sprayer approach is preferred.
Caution/limitation: Effective on common broadleaf weeds listed; may require follow-up treatment in heavy weed infestations or extended heat/drought conditions.
Scotts Liquid Turf Builder With Plus 2 Weed Control
Brand: Scotts
Features: Quick nitrogen boost with weed control; easy to apply via hose-end sprayer; targets a broad range of common lawn weeds while feeding the grass.
Best for: Those who want a 2-in-1 solution that provides an immediate nitrogen boost and weed control for lawns with St. Augustine grass. Choose this if you regularly spray with a garden hose and want a single step.
Caution/limitation: Best results occur when weeds are actively growing; ensure proper nozzle attachment and follow label directions for safe use near desirable plants and pets.
Southern Ag Atrazine St. Augustine Weed Killer
Brand: Southern Ag
Features: Atrazine-based weed killer designed for St. Augustine and Centipede grasses; treats sizable areas with one quart covering up to 3,720 sq ft.
Best for: Lawn care routines specifically targeting St. Augustine grass, especially where traditional broadleaf herbicides are less effective. This is a specialized option for lawns with known weed species addressed by atrazine.
Caution/limitation: Atrazine products require careful application to avoid non-target plant exposure; follow label directions for safe use and timing for best results.
Ortho WeedClear Weed Killer for Lawns Ready-To-Spray
Brand: Ortho
Features: Kills weeds down to the roots with a ready-to-spray hose-end applicator; results can be visible within hours; rainproof after drying; lawn-friendly when used as directed.
Best for: Homeowners who want rapid weed suppression without manual mixing and prefer a hose-end spray system. This is better for quick spot treatments across larger areas.
Caution/limitation: Only as effective as the active ingredients allow; avoid use on stressed lawns or when rain is imminent shortly after application unless directed otherwise.
Scotts Liquid Green Max Lawn Food
Brand: Scotts
Features: Dual-action liquid fertilizer and iron supplement; claims greening in as little as three days; works on any grass type; best used regularly from spring through fall for best color and health.
Best for: Lawn owners focusing on color enhancement and general nourishment, rather than weed control alone. It pairs well with weed control products in a broader lawn program.
Caution/limitation: Not a weed killer; combine with a separate weed control plan if weeds are a concern in the same season.
St Augustine Grass Fertilizer – Liquid Lawn Food
Brand: TPS NUTRIENTS
Features: Enhances deep green color and overall lawn appearance; builds strong roots for heat and wear resistance; fast-absorbing liquid formula for quick visible improvements in growth and color.
Best for: St. Augustine lawns seeking deeper color, stronger roots, and faster nutrient uptake, particularly in warm climates or after heat stress. Choose this for a color-first improvement plan alongside weed management.
Caution/limitation: Focuses on color and root development; may need supplementary weed control if broadleaf weeds are present in the lawn.
Buying Guide
What should you consider when selecting a liquid weed and feed for St. Augustine grass?
- Weed targets: Identify the common weeds in your yard. Some products specialize in broadleaf weeds, while others have a broader spectrum. For St. Augustine, atrazine-containing products and broadleaf herbicides are common options.
- Grass compatibility: Verify that the product is suitable for St. Augustine grass, as some formulations may be labeled for general use but perform best on certain warm-season grasses.
- Application method: Hose-end sprayers, ready-to-use sprays, and concentrate dilutions vary in ease of use. Choose based on your comfort with setup and frequency of application.
- Soil and climate: Warm climates and heat can affect herbicide performance and turf color. Consider products that also provide lawn nutrition to support stress tolerance.
- Timing and frequency: Weed control is typically more effective when weeds are actively growing. Follow label directions for application windows and intervals.
- Environmental and safety notes: Read label warnings about pets, children, and nearby plants. Use appropriate PPE if required and avoid runoff into mulch beds or water sources.
Frequently Asked Questions
- Q: Can I use liquid weed and feed on St. Augustine grass year-round? A: Use as directed by the product label and tailor timing to weed activity and seasonal growth for best results.
- Q: Do these products also fertilize the lawn? A: Many formulations include nitrogen to feed the lawn, but some products are primarily herbicides. Check the label for fertilizer content and recommended use.
- Q: Should I water after applying a liquid weed and feed? A: Most labels specify whether to water in after application. Follow the label to ensure proper product absorption and effectiveness.
- Q: Can I apply multiple products in the same season? A: It is best to space applications and avoid overlap that could cause lawn stress. Use products with compatible active ingredients as per label guidance.
- Q: Are there safety considerations for pets and children? A: Yes. Always follow the label’s safety directions, including restricted areas and any required waiting times before re-entry.
- Q: What is the best choice for a beginner? A: A ready-to-spray or ready-to-use formulation with broad-spectrum weed control and lawn fertilizer simplifies the process and reduces setup steps.