Many homeowners treat St. Augustine grass like a generic fescue, which is a fast track to a scorched or patchy lawn. This grass type has specific needs, and picking the wrong formula can actually stunt its growth during the peak of summer.
Finding the Best Lawn Fertilizers for St Augustine Grass requires a clear strategy rather than just grabbing the first bag you see. Take a moment to understand your soil profile, and you will see much better results.
Key Takeaways
- Look for fertilizers with a high iron content to achieve that deep, dark green color without forcing excessive top growth.
- Prioritize formulas that specify slow release nitrogen to provide consistent nourishment over several weeks.
- Check the phosphorus levels, as many St. Augustine soils already contain enough and do not require additional inputs.
- Consider liquid applications if you need a quick nutrient boost to recover from heat stress or yellowing.
- Verify that the label explicitly mentions compatibility with warm season grasses to prevent chemical burn.
| Top Tier Choice |  |
Sunniland St. Augustine Weed and Feed | Dual action formula | Convenient application | Specifically for St. Augustine | View on Amazon | Read Review |
| Rapid Nutrient Delivery |  |
Simple Lawn Solutions Balanced Liquid Fertilizer | Quick absorption | Easy to spray | Balanced nutrient profile | View on Amazon | Read Review |
| Targeted Growth Booster |  |
St. Augustine Liquid Lawn Food | High nitrogen concentration | Promotes runners | Fast acting | View on Amazon | Read Review |
| Phosphorus Free Support |  |
Sunniland St. Augustine Granular Fertilizer | Slow release nitrogen | Environmentally conscious | Large area coverage | View on Amazon | Read Review |
| Reliable Standard Maintenance |  |
Scotts Turf Builder Lawn Food | Trusted performance | Versatile application | Consistent results | View on Amazon | Read Review |
| Two In One Defense |  |
Scotts SummerGuard Fertilizer and Insecticide | Feeds and kills bugs | Summer specific | Convenient application | View on Amazon | Read Review |
| Broadleaf Weed Solution |  |
Scotts Turf Builder Weed and Feed | Kills common weeds | Feeds lawn | Well-known formula | View on Amazon | Read Review |
| Iron Rich Greening |  |
Scotts Liquid Green Max Food | High iron content | Fast greening | Liquid ease | View on Amazon | Read Review |
| Small Area Restorer |  |
Scotts EZ Patch Repair Mix | Includes mulch and fertilizer | Easy spot repair | High success rate | View on Amazon | Read Review |
| Slow Release Specialist |  |
Fertilome High Iron Lawn Fertilizer | Slow release nitrogen | High iron content | Balanced NPK | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed and Feed
This is your best all-around performer for maintaining a healthy yard while managing pesky invaders. It combines essential fertilization with targeted weed control, making it a highly efficient solution for homeowners who want to tidy up their lawn in one go.
Keep in mind that this is a granular product, so you will need a reliable spreader to ensure even distribution. Using it during the peak growing season yields the most noticeable results for your St. Augustine turf.
- Brand:Sunniland
- Type:Granular
- Coverage:5000 sq ft
- Function:Weed and feed
- Additional Feature:Controls common lawn weeds
- Additional Feature:Promotes thick turf growth
- Additional Feature:Granular delivery system
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Simple Lawn Solutions Balanced Liquid Fertilizer
If you are dealing with a lawn that looks hungry, this liquid concentrate is an excellent way to provide immediate support. The 16-4-8 NPK ratio offers a balanced approach that supports both vigorous top growth and deeper root systems.
Because it is a liquid, it is incredibly easy to mix with water and spray across your yard. Just be aware that liquid applications often require more frequent follow-ups compared to slow-release granular alternatives.
- Brand:Simple Lawn Solutions
- Type:Liquid
- Formula:16-4-8
- Weight:32 Ounce
- Function:Growth booster
- Additional Feature:Concentrated liquid formula
- Additional Feature:Suitable for any grass
- Additional Feature:Spring and summer application
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St. Augustine Liquid Lawn Food
This compact bottle is designed specifically to help your grass develop new runners, which is essential for filling in thin patches. Its high nitrogen formula is essentially a wake-up call for your lawn, pushing it toward a deep, rich green color.
It is a fantastic tool for spot treating areas that seem to be struggling compared to the rest of the yard. You will appreciate the simple mix and feed process, which cuts down on the physical labor often associated with lawn care.
- Brand:Generic/St. Augustine
- Type:Liquid
- Weight:8 oz
- Function:Growth promoter
- Additional Feature:Supports root development
- Additional Feature:Easy to mix
- Additional Feature:Fast nutrient delivery
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Sunniland St. Augustine Granular Fertilizer
Many soil types already have enough phosphorus, and this phosphorus-free formula is a smart way to fertilize without causing unnecessary runoff. The slow-release nitrogen ensures that your grass gets a steady diet over several weeks rather than a massive, fleeting spike.
This is a great pick if you want to focus on long-term health rather than just a quick cosmetic fix. It comes in a two-pack, which is perfect for covering larger lawns in a single afternoon.
- Brand:Sunniland
- Type:Granular
- Formula:20-0-6
- Coverage:10,000 sq ft
- Weight:40 lb total
- Additional Feature:Phosphorus free
- Additional Feature:Steady nutrient release
- Additional Feature:Durable bag packaging
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Scotts Turf Builder Lawn Food
You likely recognize this name, and for good reason, as it serves as the industry standard for general lawn health. It works effectively on almost all grass types, providing a consistent feeding that keeps your lawn resilient against the heat.
While it is a general-purpose product, it performs quite well on St. Augustine when applied according to the bag instructions. It is best used as part of a seasonal maintenance routine to keep your grass strong throughout the year.
- Brand:Scotts
- Type:Granular
- Coverage:5,000 sq ft
- Weight:12.5 lbs
- Additional Feature:All grass types
- Additional Feature:Easy to spread
- Additional Feature:Promotes steady growth
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Scotts SummerGuard Fertilizer and Insecticide
Summer heat often brings out unwanted pests that can devastate your lawn, so this dual-action product is a lifesaver. It feeds your St. Augustine while simultaneously acting as an insect killer to stop damage before it really starts.
This is a proactive way to handle the harshest months of the year when your grass is under the most stress. It simplifies your chore list by combining two necessary tasks into one effective treatment.
- Brand:Scotts
- Type:Granular
- Coverage:5,000 sq ft
- Weight:13.35 lbs
- Function:Fertilizer and insecticide
- Additional Feature:Insect control included
- Additional Feature:Heat stress management
- Additional Feature:Protects against damage
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Scotts Turf Builder Weed and Feed
If your lawn is being overrun by clover and dandelions, this product is designed to target those intruders while providing necessary fuel for your St. Augustine. It is a workhorse for mid-season maintenance when weeds are most active and visible.
Be sure to apply this when the grass is slightly damp, as that helps the weed-killing ingredients adhere to the leaves of the target plants. It is a straightforward way to clean up your lawn's appearance while boosting its health.
- Brand:Scotts
- Type:Granular
- Coverage:5,000 sq ft
- Weight:14.29 lbs
- Function:Weed and feed
- Additional Feature:Dandelion control
- Additional Feature:Clover elimination
- Additional Feature:Turf thickening
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Scotts Liquid Green Max Food
Sometimes your grass is healthy but just lacks that deep, vibrant color, and that is where this iron supplement shines. The 2-in-1 formula provides both primary nutrients and iron to create a darker green turf in a very short time.
Since it is a liquid, it is ideal for a quick visual improvement before a backyard party or event. It is versatile enough to be used on any grass type, making it a handy tool to keep in your shed.
- Brand:Scotts
- Type:Liquid
- Function:Fertilizer and iron
- Additional Feature:2-in-1 formula
- Additional Feature:Rapid absorption
- Additional Feature:Suitable for any grass
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Scotts EZ Patch Repair Mix
Every lawn has those frustrating bare spots that refuse to grow, and this kit is specifically designed to handle those failures. It combines mulch, fertilizer, and seed to create the perfect environment for new growth to take hold in damaged areas.
It is not meant for your whole yard, but for those troublesome patches that look thin or worn. Using this consistently in small spots will help your lawn look uniform and manicured rather than patchy.
- Brand:Scotts
- Type:Repair mix
- Coverage:170 sq ft
- Weight:7.5 lbs total
- Function:Patch repair
- Additional Feature:Contains fertilizer
- Additional Feature:Holds moisture
- Additional Feature:Specifically for St. Augustine
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Fertilome High Iron Lawn Fertilizer
The 15-0-15 ratio in this blend is excellent for those who want a balanced feeding that doesn't cause a massive, unsustainable surge of growth. The added iron ensures your St. Augustine stays a deep green, which is a common struggle for many homeowners.
The slow-release nitrogen means you won't have to mow your lawn twice a week just to keep up with the growth. It is a professional-grade approach to long-term soil and grass management.
- Brand:Fertilome
- Type:Granular
- Formula:15-0-15
- Weight:16 lbs
- Function:Slow-release fertilizer
- Additional Feature:High iron for color
- Additional Feature:Gentle on grass
- Additional Feature:Supports warm-season varieties
Frequently Asked Questions
How often should I fertilize my St. Augustine grass?
You should aim to fertilize every six to eight weeks during the primary growing season. This usually results in four to five applications per year depending on your local climate.
Will high nitrogen fertilizer kill my grass?
It can if you apply too much at once or use a product with too much quick-release nitrogen. Always follow the bag instructions carefully and water the granules into the soil immediately to prevent fertilizer burn.
Can I use a weed and feed product?
Yes, but you must select a product specifically formulated for St. Augustine grass. Many general weed and feed mixtures contain chemicals that will damage or kill this particular grass type, so read the label for compatibility warnings.
Should I water after applying fertilizer?
Yes, you absolutely should water your lawn after application. This helps move the nutrients into the root zone where the grass can actually use them. Skipping this step can lead to nutrient loss through evaporation or runoff.
What is the best NPK ratio for this grass?
You generally want a balanced approach with a focus on nitrogen. A ratio like 15-0-15 or 16-4-8 provides the necessary nitrogen for growth and enough potassium to support drought tolerance and overall root health.
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