St. Augustine grass is essentially a high-maintenance diva. It demands a specific balance of nitrogen and potassium to stay thick and emerald green, and it will punish you quickly if you ignore its need for iron.
Choosing the right nutrients prevents the common trap of stunted growth or patchy yellowing. Finding the Best Fertilizers for St. Augustine Grass requires looking past flashy marketing to see the nutrient ratios that actually fuel your turf. Let’s identify the tools that keep your lawn healthy all season long.
Key Takeaways
- Prioritize fertilizers with higher nitrogen content to support the lush leaf growth that makes this grass variety attractive.
- Check the NPK ratio closely because St. Augustine often requires additional potassium to survive heat stress and drought.
- Opt for slow-release nitrogen formulas if you want consistent, long-term growth rather than a quick, unsustainable surge.
- Ensure your choice includes iron, as this specific nutrient is vital for maintaining a deep, dark green color in southern climates.
- Consider whether you need a dual-purpose product that controls weeds while feeding, or if your lawn requires a pure nutrient boost.
| Best Overall Choice |  |
Sunniland St. Augustine Weed and Feed | Dual weed and feed action | Specifically formulated for St. Augustine | Covers standard residential yards | View on Amazon | Read Review |
| Efficient Liquid Feed |  |
Simple Lawn Solutions 16-4-8 Fertilizer | Fast nutrient absorption | Easy spray bottle application | Balanced macronutrient ratio | View on Amazon | Read Review |
| Sustained Growth Specialist |  |
Sunniland 20-0-6 Slow Release Fertilizer | Slow release nitrogen | Phosphorus free formula | Durable granular texture | View on Amazon | Read Review |
| Rapid Green Booster |  |
Liquid St. Augustine Lawn Food | Promotes rich green color | Supports new runner growth | Fast nutrient delivery | View on Amazon | Read Review |
| Reliable General Fertilizer |  |
Scotts Turf Builder Lawn Food | Broad compatibility | Easy to apply | Trusted industry standard | View on Amazon | Read Review |
| Dual Action Protector |  |
Scotts SummerGuard Insect Control | Combines fertilizer and insecticide | Targets common lawn pests | Protects against summer stress | View on Amazon | Read Review |
| Broadleaf Weed Eliminator |  |
Scotts Weed and Feed | Controls dandelions and clover | Feeds and kills simultaneously | Proven granular efficacy | View on Amazon | Read Review |
| Deep Green Specialist |  |
Fertilome 15-0-15 Iron Fertilizer | High iron content | Slow release nitrogen | Ideal for warm-season grasses | View on Amazon | Read Review |
| Bulk Maintenance Solution |  |
SeedRanch High Nitrogen Fertilizer | High nitrogen formula | Bulk quantity for large lawns | Professional size packaging | View on Amazon | Read Review |
| Holistic Growth Booster |  |
Superior 15-0-15 Liquid Fertilizer | Includes humic and seaweed | Convenient attached sprayer | All season utility | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed and Feed
If you want a specialized formula designed specifically for the unique needs of St. Augustine, this is your primary candidate. It tackles the dual challenge of feeding the lawn while suppressing unwanted weeds that frequently invade warmer regions.
Because it addresses both nutrition and maintenance in a single pass, it saves you significant time during the growing season. Just be aware that because it contains a herbicide, you should follow the application timing carefully to avoid stressing the turf during extreme heat.
- Brand Name:Sunniland
- Application Type:Granular
- Coverage Area:5,000 square feet
- Additional Feature:Targeted weed control
- Additional Feature:Granular delivery system
- Additional Feature:Professional grade results
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Simple Lawn Solutions 16-4-8 Fertilizer
Liquid fertilizers act like a quick energy drink for your grass, providing immediate access to nutrients that roots can soak up right away. This balanced NPK formula offers a versatile approach for those who prefer spraying their lawn rather than spreading heavy bags of granular material.
It works well for supplemental feeding throughout the spring and summer. The trade-off is that liquid applications require more frequent visits to the lawn compared to slow-release granular versions.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:16-4-8
- Application Type:Liquid spray
- Package Weight:32 ounces
- Additional Feature:Concentrated liquid formula
- Additional Feature:Works on any grass
- Additional Feature:Spring and summer utility
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Sunniland 20-0-6 Slow Release Fertilizer
When you need a consistent nutrient supply without the risk of burning your grass, look toward slow-release options. This particular mixture focuses on nitrogen to keep the blades lush and green while excluding phosphorus to protect local water systems.
It is a solid choice for established lawns that require regular maintenance rather than a corrective overhaul. Because the release is steady, you will notice a gradual improvement in density rather than a sudden, fleeting surge of growth.
- Brand Name:Sunniland
- Formula Ratio:20-0-6
- Application Type:Granular
- Package Weight:40 pounds
- Coverage Area:10,000 square feet
- Additional Feature:Supports healthy root systems
- Additional Feature:Prevents nutrient runoff
- Additional Feature:Designed for warm-season grass
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Liquid St. Augustine Lawn Food
Think of this concentrated liquid as a targeted boost for thin or struggling areas of your yard. It focuses on encouraging new runners and deepening the color, making it ideal for high-visibility zones that need to look their best quickly.
You will find it quite simple to mix into a standard garden sprayer for spot treatments. Since it is a fast-acting supplement, it works best when used in conjunction with a base granular fertilizer program.
- Brand Name:Generic/Brand
- Application Type:Liquid
- Package Weight:8 ounces
- Additional Feature:High nitrogen formula
- Additional Feature:Easy mix and feed
- Additional Feature:Improves lawn density
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Scotts Turf Builder Lawn Food
Sometimes you just need a dependable staple that works across almost any lawn type. This classic granular food provides a reliable baseline of nutrients to help your turf stay resilient against the stresses of the changing seasons.
It is an excellent choice for a homeowner who wants a straightforward routine without needing to study complex chemical ratios. Just keep in mind that it lacks the specialized weed or insect control found in other formulas, serving strictly as a fuel source for your grass.
- Brand Name:Scotts
- Application Type:Granular
- Package Weight:12.5 pounds
- Coverage Area:5,000 square feet
- Additional Feature:All grass type support
- Additional Feature:Consistent pellet size
- Additional Feature:Standard feeding performance
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Scotts SummerGuard Insect Control
Summer heat often brings out unwanted guests in the form of lawn-damaging insects. This product acts as a protective shield, combining necessary fertilization with a chemical barrier to keep your turf safe from destructive pests.
It is a wise selection if you live in a region where grub or armyworm activity typically peaks during the warmest months. The granular application is effective, but you must water it in properly to ensure the insecticide reaches the soil surface.
- Brand Name:Scotts
- Application Type:Granular
- Package Weight:13.35 pounds
- Coverage Area:5,000 square feet
- Additional Feature:Summer specific defense
- Additional Feature:Integrated insect killer
- Additional Feature:Promotes healthy green lawn
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Scotts Weed and Feed
If your yard is starting to look more like a meadow filled with clover and dandelions, you need something with a bit more assertive capability. This granular product clears out unwanted broadleaf invaders while delivering the nutrients your grass requires to fill in those empty patches.
It is particularly effective for thick, established St. Augustine lawns that have developed a few persistent weed problems. Always wait for a calm day to apply it to ensure the granular dust stays exactly where you want it.
- Brand Name:Scotts
- Application Type:Granular
- Package Weight:14.29 pounds
- Coverage Area:5,000 square feet
- Additional Feature:Weed killing power
- Additional Feature:Lawn thickening nutrients
- Additional Feature:Standard spreader compatibility
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Fertilome 15-0-15 Iron Fertilizer
When you notice your lawn turning a pale, yellowish green, it is often a sign that you need more iron. This formula provides a balanced nutrient base coupled with high iron content to deliver that deep, dark color that makes a lawn look exceptionally healthy.
The slow-release nitrogen ensures the lawn stays fed over a longer period, reducing the frequency of your chores. It is a fantastic option for warm-season grasses that struggle to stay vibrant during the peak of summer.
- Brand Name:Fertilome
- Formula Ratio:15-0-15
- Application Type:Granular
- Package Weight:16 pounds
- Additional Feature:Nutrient dense formula
- Additional Feature:Improves turf health
- Additional Feature:Longer lasting results
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SeedRanch High Nitrogen Fertilizer
For those managing larger properties or wanting to stock up for the entire season, this high-capacity bag is a practical acquisition. With a high nitrogen count, it provides the building blocks for rapid, lush growth across large swaths of your property.
It is best suited for experienced lawn managers who know how to calibrate their spreaders for a large surface area. Because it is a 50-pound bag, you will want to store it in a dry location to prevent clumping.
- Brand Name:SeedRanch
- Formula Ratio:24-2-11
- Application Type:Granular
- Package Weight:50 pounds
- Additional Feature:Ideal for extensive coverage
- Additional Feature:Dense nutrient profile
- Additional Feature:Sturdy bag construction
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Superior 15-0-15 Liquid Fertilizer
This liquid solution is unique because it includes humic acid, fish, and seaweed, which act as a multivitamin for your soil. It is more than just nitrogen; it provides the micronutrients necessary to improve the soil structure and overall grass vitality.
The attached sprayer makes it incredibly convenient to apply as you walk around your yard. It is a perfect choice if you want to focus on long-term soil health rather than just a quick green-up.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:15-0-15
- Application Type:Liquid
- Package Weight:32 ounces
- Additional Feature:Fish emulsion base
- Additional Feature:Improves soil health
- Additional Feature:Easy to use sprayer
Frequently Asked Questions
How often should I fertilize my St. Augustine lawn?
You should aim to feed your lawn every six to eight weeks during the active growing season. Most regions require about four applications per year to maintain optimal density and color.
Can I use a fertilizer meant for Bermuda grass on my St. Augustine?
You should avoid doing this at all costs. Bermuda grass fertilizers often contain herbicides like 2,4-D that will severely damage or kill your St. Augustine grass.
Why does my grass turn yellow after I fertilize?
If the grass turns yellow shortly after application, you likely applied too much nitrogen or failed to water it in properly. This condition, known as fertilizer burn, usually resolves if you deeply irrigate the area to wash the excess salts through the soil.
Should I water after applying fertilizer?
Yes, watering is essential to move the nutrients into the root zone where the plant can use them. Apply about one quarter inch of water immediately after spreading the granules to prevent the product from sitting on the leaf blades and causing damage.
Does iron in fertilizer stain my concrete driveway?
It certainly does, and the stains can be permanent if you leave them alone. Always use a handheld spreader to apply product carefully, and sweep any stray granules off your sidewalk or driveway before you turn on the sprinklers.
