Best Weed and Feed for St Augustine Grass: Top Picks for a Lush, Weed-Free Lawn
St. Augustine grass thrives with the right blend of weed control and feeding. The following selections are tailored for Southern lawns, focusing on St. Augustine varieties (including Floratam) and similar turf. Each product combines weed suppression with fertilization to promote healthy growth and reduce future weed pressure. Below are five proven options, followed by a practical buying guide to help you compare formulations, application timing, and safety considerations.
| Brand | Type | Notes | |
|---|---|---|---|
| Scotts | SI3313B 3313b Bonus Weed & Feed | Weed Killer + Fertilizer | Controls southern weeds; builds deep roots |
| BioAdvanced | 3-in-1 Weed and Feed for Southern Lawns, 10 lb | Weed Killer + Fertilizer | 6-month weed prevention; suited for Floratam and Bermudagrass mix |
| Southern Ag | Atrazine St. Augustine Weed Killer 32oz | Herbicide | Targets St. Augustine and Centipede for weed control |
| Ferti-lome | St. Augustine Weed & Feed 15-0-4 | Weed Killer + Fertilizer | Pre-emergent & post-emergent activity for St. Augustine |
| LESCO | St. Augustine Weed and Feed with Penoxsulam, 50 lb | Fertilizer + Herbicide | Slow release for up to 8 weeks; Floratam tolerant |
Note: Always read product labels for specific lawn types, application timing, and your local climate. The following sections showcase five options and summarize how each can help manage weeds while feeding St. Augustine grass.
Scotts SI3313B 3313b Bonus Weed & Feed
Scotts Turf Builder Bonus S Southern Weed & Feed combines weed control with fertilizer to encourage dense turf that crowds out future weeds. It targets common southern weeds such as dollarweed, clover, dandelion, chickweed, oxalis, henbit, purslane, and more as listed. Apply to a dry lawn when grass and weeds are actively growing; water in immediately after application to activate the formulation. This product emphasizes a balance between weed suppression and root development to support a robust St. Augustine lawn.
BioAdvanced 3-in-1 Weed And Feed For Southern Lawns, 10 Lb
This formulation is designed for Southern lawns, including St. Augustinegrass (Floratam) and Bermudagrass blends. The product provides up to six months of weed prevention while delivering a lawn fertilizer that supports turf health and color. It kills listed broadleaf weeds such as dandelion and dollarweed and helps maintain a healthy lawn with ongoing protection against new weeds.
Southern Ag Atrazine St. Augustine Weed Killer
This atrazine-based weed killer is formulated to control weeds specifically in St. Augustine grass and Centipede. Each quart covers a sizable area (3,720 sq ft). The product is designed for targeted weed suppression while allowing the turf to recover with minimal disruption to the lawn’s overall health. Consider compatibility with your lawn mix and follow label directions for best results.
Fertilome (13917) St. Augustine Weed & Feed 15-0-4
This product combines pre-emergent and post-emergent weed control with a 15-0-4 fertilizer mix. It is designed for Centipede, Zoysia, and St. Augustine lawns, making it a versatile option for mixed lawns. It is not recommended for Bermuda or certain northern grasses, so verify your lawn type before application. The formulation aims to curb existing weeds while sustaining turf growth and health.
LESCO 50 lb. St. Augustine Grass Weed And Feed
Lesco Professional St. Augustine Weed and Feed is a large-format option designed for broader lawn applications. It features a 50 lb bag with slow-release nutrients and penoxsulam as part of its weed control strategy. The product is designed to be safe for Floratam varieties when used as directed and provides ongoing feeding to support turf density while suppressing weeds. Effective timing and proper application are key to achieving optimum results.
Buying Guide: Key Considerations For Weed And Feed On St Augustine
- Grass compatibility: Confirm the product is labeled for St. Augustine, Floratam, or related southern turf. Some formulations are specifically tailored for southern lawns and may not perform as well on northern grasses.
- Weed spectrum: Review which weeds are targeted (dandelion, dollarweed, clover, chickweed, crabgrass, etc.). Different products offer pre-emergent, post-emergent, or both; choose based on observed weed pressure.
- Fertilizer balance: Look at the N-P-K ratio to ensure it supports growth without encouraging excessive leafiness. The presence of slow-release nutrients can provide longer-lasting feeding and reduce the need for frequent applications.
- Application timing: Some products require dry conditions before application and watering after, while others emphasize weekly or monthly cycles. Align timing with local climate and mowing schedules.
- Safety and lawn type: Check whether the product is safe for Floratam and compatible with mixed grass types in your yard. Some formulas are not suitable for Bermuda or northern grasses.
- Environment and pets: Consider the product’s environmental impact and the recommended waiting period before re-entry after application, especially in homes with children or pets.
- Coverage and bag size: For large lawns, a 50 lb bag or equivalent bulk product may be more economical, but ensure the application equipment and spreader settings match the product’s instructions.
- Layering and restrictions: Avoid combining multiple weed-control products in a single application unless explicitly approved by the labels. Always follow label directions to prevent turf damage.
Practical tips for best results
- Water in after application when required, to activate weed killers and help nutrients reach the root zone.
- Apply during periods of active growth for St. Augustine, typically in spring or early fall, avoiding extreme heat or drought conditions.
- Monitor for re-growth and plan a follow-up application window that aligns with your region’s growing cycle.
- Keep mowing height appropriate for St. Augustine to reduce stress and improve weed suppression.