St. Augustine grass acts like a hungry diva in your backyard. It demands consistent, high-nitrogen fuel to maintain that lush, deep green carpet appearance.
If you pick the wrong nutrient ratio, you might end up with thin blades or yellowing patches that never recover. Selecting the Best Fertilizers for St. Augustine Grass requires matching your soil needs to the right feeding schedule. Let’s run through the top candidates to keep your lawn thriving.
Key Takeaways
- Prioritize formulas with high nitrogen content, as this grass type requires significant amounts to sustain thick, green growth.
- Check the phosphorus level, because many established warm-season lawns thrive better with lower phosphorus inputs to avoid soil buildup.
- Consider the difference between fast-release liquid sprays for quick color and slow-release granules for long-term root health.
- Look for added micronutrients like iron, which help provide that deep emerald color without forcing excessive, weak blade elongation.
- Always match your total bag weight or container volume to the square footage of your lawn to ensure proper coverage and avoid over-application.
| Best Overall Maintenance |  |
Sunniland St. Augustine Weed and Feed | Dual action formula | St. Augustine specific | Simplifies weed control | View on Amazon | Read Review |
| Versatile Liquid Boost |  |
Simple Lawn Solutions Balanced Liquid Fertilizer | Rapid nutrient absorption | Easy spray application | Works on all grasses | View on Amazon | Read Review |
| Rapid Green Delivery |  |
St. Augustine Liquid Lawn Food | Fast green color | Supports root growth | Encourages new runners | View on Amazon | Read Review |
| Sustained Growth Specialist |  |
Sunniland St. Augustine Slow Release Granular | Steady nitrogen release | Phosphorus free formula | Covers large areas | View on Amazon | Read Review |
| Nutrient Dense Supplement |  |
Superior Liquid Lawn Fertilizer 15-0-15 | Includes humic acid | Contains seaweed extract | Built-in sprayer | View on Amazon | Read Review |
| Reliable General Purpose |  |
Scotts Turf Builder Lawn Food | Consistent performance | Easy to find | Wide compatibility | View on Amazon | Read Review |
| Pest Defense Strategy |  |
Scotts SummerGuard Insect Control Fertilizer | Combats common pests | Feeds and protects | Standard granular application | View on Amazon | Read Review |
| Professional Grade Results |  |
The Andersons PGF Complete Fertilizer | Professional grade humic | Micro-sized granules | High-quality ingredients | View on Amazon | Read Review |
| Iron Rich Formula |  |
Fertilome Centipede and St. Augustine Fertilizer | High iron content | Slow release nitrogen | Safe for warm-season | View on Amazon | Read Review |
| Bulk Feeding Powerhouse |  |
SeedRanch St. Augustine High-Performance Fertilizer | High nutrient concentration | Cost-effective bulk size | Strong potassium levels | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed and Feed
If you want to simplify your lawn care routine, this product is a solid choice because it handles two chores at once. It provides essential nutrients for your St. Augustine grass while simultaneously targeting broadleaf weeds. It is like having a gardener and a bodyguard working on your lawn at the same time.
It is designed specifically for the unique needs of St. Augustine, so you do not have to worry about the typical chemistry clashes that occur with generic products. Keep in mind that you should time your application carefully to ensure the weed-killing component works effectively without stressing the turf during extreme heat.
- Brand Name:Sunniland
- Coverage Area:5,000 sq ft
- Additional Feature:Kills broadleaf weeds
- Additional Feature:Promotes dense growth
- Additional Feature:Easy granular application
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Simple Lawn Solutions Balanced Liquid Fertilizer
This liquid formula is fantastic if you prefer a rapid nutrient delivery system that works through both the roots and the blades. Because it is a spray, you can cover your lawn quite quickly and achieve a uniform application that granular options sometimes miss.
It works well for a quick green-up during the growing season. Just be aware that because it is a liquid, you will likely need to apply it more frequently than you would a slow-release granular product to maintain those results.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:16-4-8
- Application Type:Liquid spray
- Weight Or Volume:32 Ounce
- Additional Feature:Concentrated formula
- Additional Feature:Great for spring growth
- Additional Feature:Convenient spray bottle
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St. Augustine Liquid Lawn Food
This concentrated liquid is built to give your lawn a visible color boost when it is looking a bit tired. It focuses on high nitrogen, which is the engine behind that deep emerald green color every homeowner wants.
It is particularly useful for encouraging new runners to fill in thin patches. However, since it is a high-nitrogen formula, you must be careful not to over-apply, as pushing growth too fast can sometimes leave the grass vulnerable to disease.
- Brand Name:Generic
- Application Type:Liquid
- Weight Or Volume:8 oz
- Additional Feature:Concentrated nutrient blend
- Additional Feature:Fast-acting formula
- Additional Feature:Supports thick growth
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Sunniland St. Augustine Slow Release Granular
When you want your lawn to stay fed for weeks on end, turn to this slow-release granular option. It releases nitrogen steadily, ensuring your grass has a consistent food supply without the sudden surges that lead to excessive mowing.
The fact that it is phosphorus-free is a major benefit if you live in an area with strict environmental runoff regulations. This is a workhorse product, but remember that it requires proper irrigation after application to help the granules break down into the soil.
- Brand Name:Sunniland
- Formula Ratio:20-0-6
- Application Type:Granular
- Coverage Area:5,000 sq ft
- Weight Or Volume:20 lb bags
- Additional Feature:Two pack convenience
- Additional Feature:Prevents nutrient spikes
- Additional Feature:Sustainable for soil
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Superior Liquid Lawn Fertilizer 15-0-15
This liquid fertilizer is packed with humic acid, fish, and seaweed, making it a more holistic approach to lawn health than basic chemical mixes. It provides the necessary potassium to help your grass handle heat stress, which is vital for St. Augustine during the summer months.
The included sprayer attachment makes it very easy to get started. Just keep an eye on your sprayer calibration to ensure you are not emptying the bottle too quickly across your square footage.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:15-0-15
- Application Type:Liquid
- Weight Or Volume:32 Ounce
- Key Additives:Fish and seaweed
- Additional Feature:All season formula
- Additional Feature:Improves soil quality
- Additional Feature:Enhances heat resistance
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Scotts Turf Builder Lawn Food
Sometimes you just need a dependable staple that works well on almost any lawn type. This classic granular fertilizer is incredibly easy to find and use, acting as a reliable baseline for your standard seasonal feeding schedule.
It will help your lawn build a strong foundation, but it lacks the specialized weed or insect fighting additives found in other options. Think of it as your daily multivitamin rather than a medical treatment for specific lawn issues.
- Brand Name:Scotts
- Application Type:Granular
- Coverage Area:5,000 sq ft
- Weight Or Volume:12.5 lbs
- Additional Feature:Simple granular dispersal
- Additional Feature:Strengthens grass roots
- Additional Feature:All grass types
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Scotts SummerGuard Insect Control Fertilizer
Summer brings heat, and heat often brings unwanted lawn pests that can chew through your St. Augustine. This product solves that problem by combining a standard fertilizer with an insect control agent to protect your turf while it grows.
It is a great choice if you notice small brown patches or signs of insect activity during the warmer months. Just make sure you do not use it if you are planning to overseed, as the insect-killing properties can interfere with germination.
- Brand Name:Scotts
- Coverage Area:5,000 sq ft
- Weight Or Volume:13.35 lbs
- Additional Feature:Dual-action defense
- Additional Feature:Protects against damage
- Additional Feature:Season-specific support
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The Andersons PGF Complete Fertilizer
If you want to achieve that golf course look, this professional-grade formula is your best bet. The addition of 7% humic DG helps improve the soil structure, which in turn allows the grass to better utilize the nitrogen and potassium in the mix.
It is formulated to be micro-sized, meaning the particles are smaller and disappear into the canopy much faster than traditional large granules. It is a premium product that requires a bit more attention to detail during application to ensure even coverage.
- Brand Name:The Andersons
- Formula Ratio:16-4-8
- Application Type:Granular
- Coverage Area:5,000 sq ft
- Key Additives:7% Humic DG
- Additional Feature:Superior soil conditioning
- Additional Feature:Rapid particle breakdown
- Additional Feature:Deep green color
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Fertilome Centipede and St. Augustine Fertilizer
This fertilizer is an excellent choice for St. Augustine because it is high in iron, which is the secret ingredient for that deep, dark green color that makes your neighbors jealous. It is a slow-release formula, so it feeds your lawn gently and effectively over time.
It is designed to be gentle on warm-season grasses, meaning you do not have to stress about burning your lawn when the temperatures rise. Because of the high iron content, be mindful of your sidewalks and walkways, as it can leave rust-colored stains if spilled.
- Brand Name:Fertilome
- Formula Ratio:15-0-15
- Application Type:Granular
- Weight Or Volume:16 lbs
- Key Additives:High iron
- Additional Feature:Prevents grass stress
- Additional Feature:Consistent growth feed
- Additional Feature:Professional blend
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SeedRanch St. Augustine High-Performance Fertilizer
This is a serious amount of fertilizer, making it ideal for those who have larger properties or want to stock up for the entire season. With a 24-2-11 ratio, it packs a significant punch of nitrogen and potassium to support vigorous growth and health.
It provides a strong, balanced diet for your lawn without any unnecessary fluff. Since this comes in a large 50-pound bag, it is best suited for homeowners who have the storage space and want to tackle their entire lawn in one go.
- Brand Name:SeedRanch
- Formula Ratio:24-2-11
- Application Type:Granular
- Weight Or Volume:50 lbs
- Additional Feature:Supports vigorous growth
- Additional Feature:Long-lasting supply
- Additional Feature:Balanced mineral profile
Frequently Asked Questions
How often should I fertilize my St. Augustine lawn?
You should aim to fertilize your lawn about four to six times per year during the active growing season. Space your applications roughly six to eight weeks apart to ensure a steady supply of nutrients.
Will fertilizer kill my grass if I use too much?
Yes, applying too much fertilizer can cause nitrogen burn, which manifests as yellow or brown scorched patches. Always follow the manufacturer guidelines regarding the specific square footage of your yard to avoid over-applying.
Should I water after applying fertilizer?
You should almost always water your lawn lightly after applying granular fertilizer to help the nutrients reach the soil. This process, often called watering in, also helps wash the particles off the grass blades to prevent chemical damage.
Can I use a weed and feed product on St. Augustine?
You must be very careful, as some common herbicide ingredients used in weed and feed products can severely damage St. Augustine grass. Always look for a label that specifically lists St. Augustine as a safe variety before you buy.
Is it better to fertilize before or after mowing?
You should fertilize after you have finished mowing your lawn. This ensures that the granules can settle directly onto the soil surface without being sucked up by your mower deck or bagger.
