Why does your St. Augustine grass look patchy despite your best efforts? A thick, green lawn relies on specific nutrients that standard blends often miss.
Identifying the Best Lawn Fertilizers for St Augustine starts with understanding your soil needs. A little research goes a long way toward building a healthy yard that survives the summer heat.
Key Takeaways
- Prioritize formulas with lower phosphorus levels, as St. Augustine grass typically requires less of this nutrient than other turf varieties.
- Check the NPK ratio on the label, which lists nitrogen, phosphorus, and potassium percentages, to ensure it matches your seasonal growth goals.
- Opt for slow-release nitrogen sources to provide a steady supply of nutrients rather than a quick spike that causes excessive blade growth.
- Confirm the presence of Atrazine if you need a two-in-one product to handle broadleaf weeds alongside your regular feeding schedule.
- Pay attention to the square footage coverage per bag to ensure you have enough material to treat your entire property thoroughly.
| Best Overall Maintenance |  |
Sunniland St. Augustine Weed & Feed | Dual weed and feed | Easy granular distribution | Standardized 5,000 square coverage | View on Amazon | Read Review |
| Rapid Nutrient Booster |  |
St. Augustine Liquid Lawn Food | Rapid nutrient uptake | Promotes rich green color | Supports healthy root runners | View on Amazon | Read Review |
| Heavy Duty Professional Choice |  |
SeedRanch St. Augustine 24-2-11 Fertilizer | High nitrogen for density | Bulk quantity for large lawns | Professional grade analysis | View on Amazon | Read Review |
| Phosphorus Free Feed |  |
Sunniland St. Augustine 20-0-6 Fertilizer | Environmentally conscious phosphorus-free | Sustained slow-release nitrogen | Covers 10,000 sq ft total | View on Amazon | Read Review |
| Iron Rich Colorant |  |
Fertilome 15-0-15 Centipede Lawn Fertilizer | Significant iron content | Multi-grass compatibility | Slow-release feeding | View on Amazon | Read Review |
| Reliable Universal Staple |  |
Scotts Turf Builder Lawn Food | Highly accessible brand | Even nutrient distribution | Trusted performance standards | View on Amazon | Read Review |
| Precision Spring Spray |  |
Advanced 16-4-8 Liquid Fertilizer | Instant nutrient absorption | Balanced 16-4-8 ratio | Easy hose-end application | View on Amazon | Read Review |
| Dual Action Protector |  |
Scotts SummerGuard Lawn Food | Combines feeding and protection | Targets common lawn insects | Seasonal stress support | View on Amazon | Read Review |
| Common Weed Eradicator |  |
Scotts Turf Builder Weed & Feed | Effectively targets broadleaf weeds | Feeds while killing weeds | Standard 5,000 sq ft | View on Amazon | Read Review |
| Potent Post-Emergent Power |  |
Fertilome St. Augustine Weed & Feed | Contains effective Atrazine | Dual pre and post-emergent | Specifically for southern grasses | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed & Feed
If you want a straightforward solution for your St. Augustine grass, this is your go-to. It tackles both weed suppression and nutritional needs in a single pass, which saves you a significant amount of time during the growing season.
It performs best for homeowners who prefer a granular application that covers a standard 5,000 square foot area. Just remember that because it includes a weed control agent, you should be careful to avoid applying it near ornamental flower beds where the chemicals could migrate.
- Brand Name:Sunniland
- Formula Type:Granular
- Total Coverage:5,000 sq ft
- Application Method:Broadcast spreader
- Additional Feature:Specifically formulated for St. Augustine
- Additional Feature:Combined pre and post-emergent action
- Additional Feature:Consistent granular particle size
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St. Augustine Liquid Lawn Food
Sometimes your grass needs a quick pick-me-up rather than a heavy granular treatment. This liquid concentrate is perfect for those moments when you notice pale coloring or stunted development in your runners.
The high nitrogen formula is designed to fast-track delivery directly to the foliage and roots. Because it is a liquid, it does not provide the long-term, slow-release benefits of solid pellets, so plan to use it as a supplement rather than a seasonal replacement.
- Formula Type:Liquid concentrate
- Application Method:Hose-end sprayer
- Bag Weight:8 oz
- Additional Feature:Easy to mix
- Additional Feature:Fast-acting nitrogen formula
- Additional Feature:Ideal for spot treatments
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SeedRanch St. Augustine 24-2-11 Fertilizer
When you have a larger property or a lawn that is starving for nutrients, reach for this 50-pound bag. The high nitrogen content makes it a workhorse for density, helping your grass fill in thin patches with vigor.
This is an industrial-sized bag meant for those who are serious about turf management. It is quite heavy, so ensure you have a sturdy spreader and the physical stamina to navigate a large lawn before you commit to this quantity.
- Brand Name:SeedRanch
- Formula Type:Granular
- Bag Weight:50 lbs
- Additional Feature:Balanced NPK ratio
- Additional Feature:Designed for warm-season grasses
- Additional Feature:Encourages deep root growth
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Sunniland St. Augustine 20-0-6 Fertilizer
Many local regulations restrict phosphorus because of runoff concerns, and this formula is a responsible alternative. It relies on slow-release nitrogen to feed your lawn steadily over several weeks instead of forcing a sudden, unsustainable growth spurt.
This is an excellent option for maintaining steady green color throughout the hot summer months. Since it contains no phosphorus, it is strictly focused on blade growth rather than root establishment, so it is best used on established turf.
- Brand Name:Sunniland
- Formula Type:Granular
- Total Coverage:10,000 sq ft
- Bag Weight:20 lbs per bag
- Additional Feature:Two-pack bundle
- Additional Feature:Safe for established lawns
- Additional Feature:Consistent nitrogen delivery
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Fertilome 15-0-15 Centipede Lawn Fertilizer
The addition of high iron in this formula is the secret weapon for anyone struggling with yellowing turf. It provides a deep, dark green hue that makes your yard look like a professional golf course.
This blend is versatile enough to work on St. Augustine, Zoysia, and Centipede grasses. While it excels at color enhancement, it is a lighter nitrogen feed, so it works best as a maintenance product rather than a repair solution for extremely damaged soil.
- Brand Name:Fertilome
- Formula Type:Granular
- Bag Weight:16 lbs
- Additional Feature:Balanced 15-0-15 NPK ratio
- Additional Feature:Enhances chlorophyll production
- Additional Feature:Gentle on warm-season grasses
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Scotts Turf Builder Lawn Food
If you want a dependable product that is widely available and easy to apply, this is the classic choice. It is formulated to work across diverse grass types, providing a balanced diet that encourages thick, resilient blades.
This is a great option for the casual gardener who does not want to overthink their lawn care routine. Note that this formula does not contain weed control, so it is strictly for feeding rather than fighting off invasive species.
- Brand Name:Scotts
- Formula Type:Granular
- Total Coverage:5,000 sq ft
- Bag Weight:12.5 lbs
- Additional Feature:All-weather performance
- Additional Feature:Uniform granule size
- Additional Feature:Simple application instructions
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Advanced 16-4-8 Liquid Fertilizer
Liquid fertilizers are like an intravenous drip for your lawn, delivering nutrients exactly where the plant needs them immediately. This balanced NPK blend is perfect for a spring awakening when your St. Augustine is just starting to wake from dormancy.
The concentrated spray is incredibly easy to apply with a standard hose attachment. Because liquids leach through the soil faster than granules, you will need to apply it more frequently to maintain the same level of growth throughout the peak summer heat.
- Brand Name:Simple Lawn Solutions
- Formula Type:Liquid concentrate
- Bag Weight:32 oz
- Additional Feature:Spring and summer formulation
- Additional Feature:Concentrated liquid solution
- Additional Feature:Universal grass compatibility
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Scotts SummerGuard Lawn Food
Summer brings heat, but it also brings unwelcome insect pests that can devastate a lawn. This product serves as both a fertilizer and an insect killer, shielding your turf from damage while keeping it lush.
It is particularly useful if you live in a region where chinch bugs or other turf-destroying insects are common during the hot months. Remember that this is a specialized product, so you should only use it when you have an active pest concern to avoid unnecessary chemical exposure.
- Brand Name:Scotts
- Formula Type:Granular
- Total Coverage:5,000 sq ft
- Bag Weight:13.35 lbs
- Additional Feature:Insect control formula
- Additional Feature:Summer heat resilience
- Additional Feature:Convenient one-step process
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Scotts Turf Builder Weed & Feed
When dandelions and clover start taking over your yard, you need a proactive defense. This granular product clears out broadleaf weeds while simultaneously giving your St. Augustine the nutrients it needs to crowd out any remaining gaps.
The granular format is perfect for targeted coverage over a standard suburban yard. Just be aware that you need to apply this when the grass is slightly damp, which helps the weed-killing particles stick to the leaves for maximum effectiveness.
- Brand Name:Scotts
- Formula Type:Granular
- Total Coverage:5,000 sq ft
- Bag Weight:14.29 lbs
- Additional Feature:Specifically targets dandelion and clover
- Additional Feature:Thickens turf density
- Additional Feature:Proven granular technology
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Fertilome St. Augustine Weed & Feed
This product stands out because it contains Atrazine, a powerful tool for knocking out tough weeds in St. Augustine lawns. It serves as a pre-emergent to stop weeds before they start and a post-emergent to handle what is already growing.
This is a robust solution for a lawn that has been poorly maintained or is currently under heavy weed pressure. Because it is so potent, you should follow the instructions strictly to ensure you do not burn your grass during high-temperature days.
- Brand Name:Fertilome
- Formula Type:Granular
- Active Ingredients:Atrazine
- Bag Weight:25.6 lbs
- Additional Feature:15-0-4 NPK ratio
- Additional Feature:Safe for Zoysia and Centipede
- Additional Feature:Long-lasting weed control
Frequently Asked Questions
How often should I fertilize my St. Augustine grass?
You should feed your lawn every six to eight weeks during the active growing season. This ensures a steady supply of nutrients as the grass spreads through runners.
Will fertilizer hurt my pets or kids?
Most fertilizers are safe once they have been watered into the soil and allowed to dry completely. Keep everyone off the lawn for at least 24 hours after application to be safe.
Why does my grass look yellow after fertilizing?
You might be dealing with iron chlorosis, which happens when the soil pH is too high for the grass to absorb iron. Adding a supplement containing chelated iron should fix the discoloration quickly.
Is it better to fertilize before or after rain?
It is best to apply fertilizer right before a light rain or to water it in manually with your irrigation system. This helps the granules dissolve and move the nutrients down to the root zone where they belong.
Can I use a weed and feed product on new sod?
Avoid using weed and feed products on new sod for at least the first three months. The herbicides in these products can be too harsh for developing roots and might kill the new grass you just installed.
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