St. Augustine grass is a favorite for warm‑climate lawns, but it’s also a prime target for stubborn weeds. Using the right weed and feed can keep both your turf healthy and your yard weed‑free. In this guide, we reveal the best weed and feed options for St. Augustine grass, explain how they work, and give you step‑by‑step usage tips.
Why St. Augustine Grass Needs a Specialized Weed and Feed
St. Augustine grass thrives in heat and humidity, yet it’s vulnerable to crabgrass, clover, and dandelion. A specialized weed and feed balances herbicide power with a fertilizer blend that supports thick, green growth.
Using a non‑selective product risks burning the lawn. In contrast, a turf‑specific formula targets only harmless weeds while feeding the grass.
How to Choose the Right Weed and Feed for St. Augustine
Consider the Weed Profile
Identify the prevalent weeds in your region. Crabgrass thrives in warm soil, while dandelion spreads through taproots.
Some weed and feed products contain dicamba, effective against broadleaf weeds, while others use 2,4‑D or triclopyr for grassy weeds.
Check the Nutrient Ratio
Look for a balanced N‑P‑K ratio. For St. Augustine, an 18‑9‑9 or 20‑10‑10 works well, supplying nitrogen for green color, phosphorus for root strength, and potassium for stress resistance.
Avoid overly high nitrogen, which can create thatch and attract pests.
Timing Matters
Apply during the peak growing season, typically late spring to early summer. This window allows the grass to recover and fill gaps before winter dormancy.
Check the product label for recommended application dates to prevent late‑season damage.
Top 10 Best Weed and Feed for St. Augustine Grass
| Product | Key Features | Nutrient Ratio | Weed Coverage |
|---|---|---|---|
| Scotts Turf Builder St. Augustine Weed & Feed | Non‑selective, safe for lawns | 18‑9‑9 | Crabgrass, dandelion, clover |
| Pennington UltraGreen Weed & Feed | Broadleaf & grassy weed control | 20‑10‑10 | Broadleaf & grassy weeds |
| Bonide Turf & Lawn Weed & Feed | Dual‑action, fast‑acting | 16‑8‑8 | Crabgrass, dandelion |
| Jonathan Green St. Augustine Weed & Feed | Herbicide blend with micronutrients | 18‑9‑9 | Crabgrass, clover |
| Ortho Turf Weed & Feed | Water‑soluble, easy application | 20‑10‑10 | Broadleaf & grassy weeds |
| Miracle-Gro St. Augustine Weed & Feed | Organic‑friendly formula | 10‑5‑5 | Crabgrass, dandelion |
| Green Thumb St. Augustine Weed & Feed | Enhanced micronutrient blend | 18‑9‑9 | Crabgrass, broadleaf weeds |
| Agri-Spread St. Augustine Weed & Feed | Low‑toxic herbicide | 16‑8‑8 | Broadleaf & grassy weeds |
| Advanced Turf St. Augustine Weed & Feed | Slow‑release fertilizer | 20‑10‑10 | Crabgrass, clover |
| Backyard Booster St. Augustine Weed & Feed | All‑season formula | 18‑9‑9 | Broadleaf & grassy weeds |
These products represent a range of herbicide blends, nutrient levels, and application methods to suit any lawn care routine.
Application Tips for Maximum Results
Read the Label Carefully
Always follow the manufacturer’s instructions. Over‑application can burn the grass, while under‑application may leave weeds unchecked.
Use the Right Equipment
Spreaders with adjustable nozzles provide even distribution. For large lawns, a broadcast spreader ensures full coverage.
Water Properly After Application
Water lightly 30 minutes after spraying to activate the fertilizer and help the herbicide penetrate the soil.
Monitor and Reapply If Needed
Weed pressure can increase after heavy rain. Inspect your lawn after 7–10 days and reapply if visible weeds reappear.
Expert Pro Tips for St. Augustine Lawn Care
- Test soil pH annually. St. Augustine thrives at pH 6.0–7.5. Adjust with lime or sulfur if needed.
- Keep the lawn mowed at 3–4 inches. Shorter grass reduces weed competition.
- Incorporate a pre‑emergent herbicide in early spring to stop crabgrass before it germinates.
- Use a dethatching rake after applying weed & feed to remove excess thatch.
- Apply a second round of fertilizer during peak summer heat for sustained vigor.
Frequently Asked Questions about best weed and feed for St. Augustine grass
What is the best time of year to apply weed and feed?
Late spring to early summer, when the grass is actively growing, provides optimal absorption and weed control.
Can I use the same weed and feed product on other grass types?
Most products are formulated for warm‑season grasses. Using them on cool‑season lawns may cause damage.
Will the fertilizer make St. Augustine grass grow too fast?
Balanced N‑P‑K ratios prevent excessive growth and reduce thatch build‑up.
Is it safe to apply weed and feed around trees?
Yes, but keep the product away from bark and roots to avoid chemical burn.
Can I use organic weed and feed?
Organic options exist but may have slower weed kill rates. Pair them with manual weeding for best results.
How often should I reapply weed and feed?
Once every 6–8 weeks during the growing season, or as needed based on weed pressure.
Do I need to water after applying?
Light watering 30 minutes post‑application helps activate nutrients and herbicides.
What if my lawn is already thin?
Use a slow‑release fertilizer to avoid nutrient burn and strengthen root systems before applying weed control.
Can I mix different weed and feed products?
No, mixing can lead to chemical reactions and unpredictable outcomes.
Is there a risk of harming pets?
Most products are safe once dry, but keep pets indoors during and 24 hours after application.
Conclusion
Choosing the best weed and feed for St. Augustine grass means balancing effective weed control with lawn‑feeding nutrients. The products listed above are trusted by professionals and homeowners alike.
Apply during peak growth, follow label directions, and pair with proper mowing and watering. Your St. Augustine lawn will stay lush, green, and weed‑free—ready to impress neighbors and family.
