When you spot the yellow patches on your St. Augustine lawn after a dry spell, you’ll wonder which fertilizer can revive it without burning the roots. The right N‑P‑K mix, slow‑release nitrogen, and weed‑control features can make all the difference, but each product varies in timing, application method, and compatibility with your soil’s pH. Knowing these nuances will help you choose the most suitable formula and keep your lawn lush all season.
| Espoma Organic Spring Lawn Booster 8-0-0 30 lb |  | Organic Essential | NPK Ratio: 8‑0‑0 | Coverage Area: 5,000 sq ft | Formulation Type: Granular (slow‑release) | VIEW LATEST PRICE | Read Our Analysis |
| Scotts Turf Builder Weed & Feed 14.29 lb |  | Weed‑Control Power | NPK Ratio: 14‑29‑?? (weed‑kill fertilizer) | Coverage Area: 5,000 sq ft | Formulation Type: Granular (weed‑kill/fertilizer) | VIEW LATEST PRICE | Read Our Analysis |
| Sunniland St. Augustine Weed & Feed Fertilizer (5000 sq ft) |  | St. Augustine Specialist | NPK Ratio: 1‑0‑0 (mixing ratio) | Coverage Area: 5,000 sq ft | Formulation Type: Granular | VIEW LATEST PRICE | Read Our Analysis |
| Advanced 16-4-8 NPK Liquid Fertilizer (32 oz) |  | Liquid Boost | NPK Ratio: 16‑4‑8 | Coverage Area: Not specified (per gallon) | Formulation Type: Liquid | VIEW LATEST PRICE | Read Our Analysis |
| Almighty 20-0-10 Lawn Fertilizer (25 lb) – Release Release Nitrogen. Trace Micronutrients |  | Slow‑Release Pro | NPK Ratio: 20‑0‑10 | Coverage Area: 6,250 sq ft | Formulation Type: Granular (slow‑release) | VIEW LATEST PRICE | Read Our Analysis |
| Pennington Full Season Lawn Fertilizer 32-0-5 4M 11.2lb |  | Full‑Season Champion | NPK Ratio: 32‑0‑5 | Coverage Area: 4,000 sq ft | Formulation Type: Granular (polymer‑coated) | VIEW LATEST PRICE | Read Our Analysis |
| Scotts EZ Patch Lawn Repair for St. Augustine Lawns 3.75 lb |  | Repair Solution | NPK Ratio: Controlled‑release (no NPK listed) | Coverage Area: 85 sq ft | Formulation Type: Granular (mulch + fertilizer) | VIEW LATEST PRICE | Read Our Analysis |
More Details on Our Top Picks
Espoma Organic Spring Lawn Booster 8-0-0 30 lb
If you’re looking for a gentle, organic boost that won’t scorch St. Augustine grass, the Espoma Organic Spring Lawn Booster 8‑0‑0 is the perfect pick. You’ll spread 30 lb across up to 5,000 sq ft using a drop or broadcast spreader in early spring. Its slow‑release nitrogen, enhanced with calcium, feeds cool‑ and warm‑season grasses—fescues, bluegrass, rye, St. Augustine, and zoysia—without burning or leaching. Certified as an organic input material, it’s environmentally safe, contains no sludges, and won’t harm soil microbes. One bag covers a whole yard, delivering lasting, balanced nutrition.
- NPK Ratio:8‑0‑0
- Coverage Area:5,000 sq ft
- Formulation Type:Granular (slow‑release)
- Target Grass:All cool‑/warm‑season grasses (including St. Augustine)
- Release Mechanism:Slow‑release nitrogen (enhanced with calcium)
- Application Method:Drop or broadcast spreader
- Additional Feature:Registered Organic Input Material
- Additional Feature:No sludges/toxic ingredients
- Additional Feature:Calcium‑enhanced nitrogen
Scotts Turf Builder Weed & Feed 14.29 lb
Scotts Turf Builder Weed & Feed 14.29 lb is ideal for homeowners who need a single‑step solution to kill common lawn weeds while feeding the grass, but it’s not suitable for St. Augustine lawns. You’ll find it kills over 50 weeds—clover, dandelion, plantain—while fertilizing Bahiagrass, Bermudagrass, Bluegrass, Centipedegrass, Fescue, Ryegrass, and Zoysiagrass. One bag covers 5,000 sq ft, but you must apply it only twice a year to a wet lawn between 60°F and 90°F, then keep pets and people off for 24 hours. Use a broadcast spreader set to 3 ½ or a drop spreader set to 5, and avoid rain for a day after use.
- NPK Ratio:14‑29‑?? (weed‑kill fertilizer)
- Coverage Area:5,000 sq ft
- Formulation Type:Granular (weed‑kill/fertilizer)
- Target Grass:All grasses except St. Augustine (not recommended)
- Release Mechanism:Immediate herbicide + fertilizer (no slow‑release)
- Application Method:Broadcast or drop spreader (settings provided)
- Additional Feature:2,4‑D & Mecoprop actives
- Additional Feature:2 applications max/year
- Additional Feature:No watering 24 hrs
Sunniland St. Augustine Weed & Feed Fertilizer (5000 sq ft)
Sunniland’s St. Augustine Weed & Feed fertilizer is the go‑to choice for homeowners who want a single product that both feeds their lawn and tackles stubborn broadleaf and dollar‑weed invasions. Its easy‑to‑spread granules cover 5,000 sq ft, delivering a 1:0:0 nitrogen‑phosphorus‑potassium mix that fuels St. Augustine grass while suppressing most broadleaf and dollar weeds. Apply twice a year—once in spring, once in fall—for ideal results. The product ranks #1,567 in garden fertilizers and holds a 4.5‑star rating from 36 reviewers, proving it’s a reliable, hassle‑free solution for a lush, weed‑free lawn.
- NPK Ratio:1‑0‑0 (mixing ratio)
- Coverage Area:5,000 sq ft
- Formulation Type:Granular
- Target Grass:St. Augustine only
- Release Mechanism:Immediate release (granules)
- Application Method:Broadcast spreader (granules)
- Additional Feature:Broadleaf & dollar weed control
- Additional Feature:2 seasonal applications
- Additional Feature:Granule easy‑spread
Advanced 16-4-8 NPK Liquid Fertilizer (32 oz)
Homeowners who want a fast‑acting, easy‑to‑apply boost for St. Augustine lawns should reach for the Advanced 16‑4‑8 NPK Liquid Fertilizer. This 32‑oz bottle delivers a balanced 16‑4‑8 formula, mixing seaweed and fish extracts for organic vigor. You’ll mix 3–5 fl oz per gallon of water, then spray during spring or summer for immediate green color and strong growth. The nitrogen spurs leaf development, phosphorus fuels root expansion, and potassium builds drought and heat tolerance. Ready‑to‑use and made in the USA, it works on any grass type, correcting deficiencies while enhancing overall lawn health.
- NPK Ratio:16‑4‑8
- Coverage Area:Not specified (per gallon)
- Formulation Type:Liquid
- Target Grass:All grass types
- Release Mechanism:Immediate liquid application
- Application Method:Sprayer (mix with water)
- Additional Feature:Seaweed & fish ingredients
- Additional Feature:Ready‑to‑use sprayer
- Additional Feature:Concentrated spray mix
Almighty 20-0-10 Lawn Fertilizer (25 lb) – Release Release Nitrogen. Trace Micronutrients
If you need a fertilizer that feeds St. Augustine grass steadily while resisting summer heat, the Almighty 20‑0‑10 (25 lb) is the top choice. Its 20‑0‑10 NPK blend supplies 45 % slow‑release nitrogen, keeping your lawn green for up to eight weeks. The added NuTrace micronutrients boost absorption, while 10 % potassium deepens roots and improves drought tolerance. One bag covers roughly 6,250 sq ft, and you can spread it easily with a broadcast spreader. You’ll see quick greening within days, no burn risk when applied as directed, and a resilient lawn that stays vibrant under summer stress.
- NPK Ratio:20‑0‑10
- Coverage Area:6,250 sq ft
- Formulation Type:Granular (slow‑release)
- Target Grass:All grass types (including St. Augustine)
- Release Mechanism:45 % slow‑release nitrogen
- Application Method:Broadcast spreader
- Additional Feature:NuTrace micronutrients included
- Additional Feature:45% slow‑release nitrogen
- Additional Feature:8‑week feeding window
Pennington Full Season Lawn Fertilizer 32-0-5 4M 11.2lb
Pennington’s Full Season Lawn Fertilizer 32‑0‑5 4M 11.2 lb is the ideal pick for St. Augustine owners who want a single, season‑long feed that keeps their grass thick, green, and healthy. You’ll spread the 11.2‑lb bag over up to 4,000 sq ft with a broadcast spreader, then water a day or two before. The polymer‑coated urea releases nitrogen slowly for four months, while 5 % iron deepens greening. Natural microbes revive soil, so the turf stays lush all year. Apply only to actively growing grass, avoid heavy‑rain forecasts, and you’ll enjoy a vibrant, thick lawn without re‑fertilizing.
- NPK Ratio:32‑0‑5
- Coverage Area:4,000 sq ft
- Formulation Type:Granular (polymer‑coated)
- Target Grass:All grass types
- Release Mechanism:Polymer‑coated urea (slow release up to 4 months)
- Application Method:Broadcast spreader
- Additional Feature:5% iron for deep greening
- Additional Feature:Natural beneficial microbes
- Additional Feature:Polymer‑coated urea
Scotts EZ Patch Lawn Repair for St. Augustine Lawns
3.75 lb
Looking for a fast, reliable fix for thin or damaged St. Augustine patches? Scotts EZ Patch Lawn Repair delivers a ready‑to‑use mulch‑fertilizer blend that covers up to 85 sq ft. The 3.75 lb bag expands as its mulch absorbs water, sealing gaps and holding soil in place. Its controlled‑release fertilizer accelerates grass establishment, promoting growth 60 % faster than untreated spots. To apply, clear dead grass, loosen compacted soil, spread the mix evenly, then water gently until saturated. You’ll see healthier, fuller St. Augustine lawns with minimal effort—perfect for quick repairs and long‑term vigor.
- NPK Ratio:Controlled‑release (no NPK listed)
- Coverage Area:85 sq ft
- Formulation Type:Granular (mulch + fertilizer)
- Target Grass:St. Augustine only
- Release Mechanism:Controlled‑release fertilizer (mulch)
- Application Method:Hand‑spread (mulch/fertilizer mix)
- Additional Feature:Mulch absorbs 6× water
- Additional Feature:60% faster patch recovery
- Additional Feature:Controlled‑release fertilizer
Factors to Consider When Choosing Lawn Fertilizer for St. Augustine Grass
When picking a fertilizer for St. Augustine, check the nutrient ratio to match the grass’s needs and guarantee the product works with your soil’s pH. Choose a formula with slow‑release nitrogen for steady growth and consider whether it includes weed‑control agents. Finally, plan the application timing and frequency to maintain your lawn healthy year‑round.
N Nutrient Ratio
If you’re aiming for a lush, emerald lawn, the nutrient ratio on your fertilizer matters most. Choose a formula with at least 16 % nitrogen—16‑4‑8 or 20‑0‑10 are ideal—to meet St. Augustus’s high nitrogen demand. Opt for slow‑release nitrogen so the grass receives a steady feed, reducing burn risk and cutting back on frequent applications. Keep phosphorus low, around 4 %, because the grass doesn’t need much of it and excess can waste resources. Boost potassium to 8‑10 % to improve stress tolerance and disease resistance. When you match these ratios, you’ll see deeper green color, stronger blades, and a lawn that stays resilient throughout the growing season.
Soil pH Compatibility
Because St. Augustus prefers slightly acidic soil, you should check that your lawn’s pH falls between 5.5 and 7.5 before selecting a fertilizer. A pH outside this window hampers nutrient absorption, so regular testing is essential. If results show a lower pH, incorporate sulfur to bring it up; if it’s higher, apply lime to lower it. Choose a fertilizer labeled for St. Augustus or for the 5.5‑7.5 range, because those formulas balance nitrogen, phosphorus, and potassium in a way the grass can readily use. Maintaining the correct pH not only boosts uptake of the applied nutrients but also supports root health, disease resistance, and overall lawn vigor. Keep a testing schedule, adjust with lime or sulfur as needed, and select pH‑compatible products for the best results.
Slow‑Release Nitrogen
Although quick‑release fertilizers can give an instant green boost, slow‑release nitrogen is the smarter choice for St. Augustus because it feeds the grass steadily over weeks or months, keeping color vibrant without causing burn or excessive growth. You’ll notice a consistent, deep‑green canopy as the nitrogen slowly becomes available, thanks to urea‑based or polymer‑coated compounds that break down gradually. This steady supply curbs the risk of fertilizer burn and cuts back on how often you need to reapply. Most formulations deliver 30‑50 % of total nitrogen in a slow‑release form, giving you a blend of quick and lasting nutrition. For St. Augustus, that balance maintains a lush, uniform lawn throughout the season without triggering unwanted, rapid growth.
Weed Control Integration
Weed‑control integration is key when picking a fertilizer for St. Augustus, because broadleaf invaders like dollarweed can overwhelm the lawn if left unchecked. Choose a product that explicitly lists St. Augustus on the label and includes a selective herbicide, such as 2,4‑D or dicamba, so you won’t damage the grass while targeting weeds. Look for a balanced N‑PK ratio that feeds the turf and a herbicide at the right concentration for active weed growth. Pair the feed with proper mowing heights, regular deep watering, and good that to keep the lawn dense and competitive. By combining nutrition and targeted weed control, you’ll maintain a lush, resilient St. Augustus carpet that resists invasion.
Application Timing & Frequency
Timing your fertilizer applications is essential for keeping St. Augustus grass healthy and vibrant. You should feed the lawn in early spring, late spring, and early fall when growth is vigorous. During the active season, apply a balanced granular or liquid fertilizer every 6‑8 weeks, adjusting the rate to the product label. Skip applications in the hottest, driest summer months, as the grass goes semi‑dormant and won’t absorb nutrients effectively. Over‑fertilizing can cause rapid, weak shoots, thatch buildup, and invite pests or disease, so stick to the recommended schedule and amount. By timing each dose to the grass’s growth cycle, you’ll maintain a lush, green St. Augustus lawn year‑round.
