St. Augustine grass demands specific nutrition, or it will turn yellow and thin out before the heat even peaks. Providing the right nutrient ratio is the primary difference between a lawn that thrives and one that struggles to survive the season.
Choosing the Best Fertilizers for St Augustine requires understanding your specific soil needs. Match your product to the current condition of your yard, and you will see the grass respond with lush, dense growth. Here is a breakdown to help you make an informed choice.
Key Takeaways
- Prioritize formulas with high iron content if you want to achieve a deep, vibrant green color.
- Always check the label to ensure the fertilizer is specifically labeled as safe for St. Augustine grass to avoid chemical burns.
- Use weed and feed products only when active weeds are present to prevent unnecessary stress on your lawn.
- Granular fertilizers with slow-release nitrogen provide a more consistent feeding schedule over several months.
- Match the nitrogen level to your grass's growth phase, opting for higher rates during the active spring and summer seasons.
| Best All-Rounder |  |
Sunniland St. Augustine Weed & Feed | Dual action weed control | Targeted St. Augustine formula | Simple single application | View on Amazon | Read Review |
| Fast Absorption Liquid |  |
Simple Lawn Solutions Balanced Liquid Fertilizer | Rapid nutrient absorption | Easy spray application | Balanced NPK ratio | View on Amazon | Read Review |
| Greening Growth Booster |  |
St. Augustine Liquid Lawn Food | Promotes dense growth | Enhances deep green color | Supports new runners | View on Amazon | Read Review |
| Professional Strength Formula |  |
SeedRanch High Nitrogen Grass Fertilizer | High nitrogen for growth | Large bag size | Effective for large lawns | View on Amazon | Read Review |
| Gentle Steady Feeder |  |
Fertilome Slow Release Lawn Fertilizer | Slow release technology | High iron content | Prevents rapid surge growth | View on Amazon | Read Review |
| Deep Color Specialist |  |
Scotts Green Max Iron Supplement | Deepens green color | Fast visual results | Iron enriched | View on Amazon | Read Review |
| Reliable Daily Nutrition |  |
Scotts Turf Builder Basic Fertilizer | Simple to apply | Foundation for growth | Reliable performance | View on Amazon | Read Review |
| Pest Defense System |  |
Scotts SummerGuard Fertilizer and Insecticide | Feeds and kills bugs | Prevents summer damage | Dual action formula | View on Amazon | Read Review |
| Heavy Duty Weed Killer |  |
Fertilome St. Augustine Weed Control | Strong weed control | Safe for St. Augustine | Pre and post emergent | View on Amazon | Read Review |
| Bare Spot Fixer |  |
Scotts EZ Patch Repair Mix | Repairs bare spots | Includes mulch and fertilizer | Easy patch application | View on Amazon | Read Review |
More Details on Our Top Picks
-
Sunniland St. Augustine Weed & Feed
This formula is your best bet if you want to tackle weeds and nutrition in one pass. It balances the specific needs of St. Augustine grass, acting like a protective shield that keeps common invasive plants from stealing nutrients.
Use this if you prefer a simplified lawn care routine. It covers 5,000 square feet, but keep in mind that you need to apply it carefully to avoid burning the lawn during peak summer heat.
- Brand Name:Sunniland
- Product Type:Weed and Feed
- Primary Benefit:Weed prevention and growth
- Target Grass:St. Augustine
- Additional Feature:Covers 5,000 square feet
- Additional Feature:Granular application
- Additional Feature:Post-emergent control
-
Simple Lawn Solutions Balanced Liquid Fertilizer
Liquid formulas act like a quick energy drink for your soil. Because it is a 16-4-8 balanced ratio, it provides immediate access to the nutrients your grass needs for steady, healthy development during the growing season.
It works well for any grass type, though St. Augustine thrives on this liquid delivery. Just remember that liquid applications require more frequent use than granular options to maintain consistent color.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:16-4-8
- Product Type:Liquid Fertilizer
- Target Grass:Any type
- Additional Feature:Concentrated formula
- Additional Feature:Spring and summer use
- Additional Feature:32 ounce bottle
-
St. Augustine Liquid Lawn Food
If your lawn looks tired, this concentrated liquid is designed to help with thicker growth and deep green color. It specifically targets the development of new runners, which helps fill in thin patches across your yard.
It is an excellent choice for a quick visual improvement. Since it comes in an 8 oz bottle, it is better suited for smaller areas or specific spots rather than treating an entire estate.
- Brand Name:St. Augustine
- Product Type:Liquid Fertilizer
- Primary Benefit:Thicker growth
- Target Grass:St. Augustine
- Additional Feature:Concentrated liquid
- Additional Feature:Spot treatment friendly
- Additional Feature:Promotes runner expansion
-
SeedRanch High Nitrogen Grass Fertilizer
This 24-2-11 mix is a powerhouse for aggressive grass growth. The high nitrogen content pushes your lawn to produce lush blades quickly, making it a favorite for those who want a noticeable transformation.
Because it is a 50-pound bag, this is the smart pick for large residential lawns. You should use a spreader to ensure even distribution, as the high concentration can cause uneven patches if thrown by hand.
- Brand Name:SeedRanch
- Formula Ratio:24-2-11
- Product Type:Granular Fertilizer
- Weight Capacity:50 lbs
- Target Grass:St. Augustine
- Additional Feature:Professional grade blend
- Additional Feature:Promotes rapid greening
- Additional Feature:Consistent nutrient release
-
Fertilome Slow Release Lawn Fertilizer
Slow-release nitrogen is like a steady drip of water in a drought. This 15-0-15 formula provides a long-term nutrient supply without the risk of an initial surge that could stress your grass.
The addition of high iron levels helps keep your lawn dark green without forcing excessive vertical growth. It is perfectly formulated for sensitive warm-season grasses that prefer a measured, consistent diet.
- Brand Name:Fertilome
- Formula Ratio:15-0-15
- Product Type:Granular Fertilizer
- Weight Capacity:16 lbs
- Target Grass:Warm-season grasses
- Additional Feature:Includes added iron
- Additional Feature:Consistent nutrient profile
- Additional Feature:Centipede and St. Augustine compatible
-
Scotts Green Max Iron Supplement
Sometimes your grass is healthy but simply lacks that vibrant emerald hue. This formula doubles as a fertilizer and an iron supplement, bringing out a deep color that standard blends often miss.
It provides visible results in just a few days. While it excels at aesthetics, treat it as a supplemental booster rather than a primary nitrogen source for high-growth periods.
- Brand Name:Scotts
- Product Type:Granular Fertilizer
- Weight Capacity:16.67 lbs
- Primary Benefit:Color enhancement
- Target Grass:All grass types
- Additional Feature:5,000 square foot coverage
- Additional Feature:Added iron supplement
- Additional Feature:Fast acting formula
-
Scotts Turf Builder Basic Fertilizer
This is the classic workhorse of lawn care. It provides the foundational nutrients your grass needs to survive the changing seasons and remain thick enough to crowd out common weeds.
It is simple to use and works on almost any grass variety. If you want a no-fuss schedule that keeps your yard consistent, this is the standard choice.
- Brand Name:Scotts
- Product Type:Granular Fertilizer
- Weight Capacity:12.5 lbs
- Target Grass:All grass types
- Additional Feature:5,000 square foot coverage
- Additional Feature:Turf builder formula
- Additional Feature:Consistent feeding
-
Scotts SummerGuard Fertilizer and Insecticide
Summer heat brings pests that can chew through your lawn before you even notice. This dual-purpose product feeds your grass while creating a barrier against bugs, acting like a security guard for your backyard.
It is ideal for the warmer months when insects are most active. Just ensure you water it in properly after application to move the ingredients into the soil where the insects live.
- Brand Name:Scotts
- Product Type:Granular Fertilizer
- Weight Capacity:13.35 lbs
- Primary Benefit:Insect protection
- Target Grass:All grass types
- Additional Feature:5,000 square foot coverage
- Additional Feature:Summer specific care
- Additional Feature:Controls lawn insects
-
Fertilome St. Augustine Weed Control
Weeds can be a persistent plague, but the Atrazine in this formula acts as a surgical strike against them. It is formulated to be safe for St. Augustine while knocking out broadleaf weeds before they take over.
It works as both a pre-emergent and post-emergent solution, giving you control over weeds at different stages. Use this if you have a specific weed problem rather than just a general need for fertilizer.
- Brand Name:Fertilome
- Formula Ratio:15-0-4
- Product Type:Granular Weed and Feed
- Weight Capacity:25.6 lbs
- Target Grass:St. Augustine and Zoysia
- Additional Feature:Contains Atrazine
- Additional Feature:Effective weed management
- Additional Feature:Granular consistency
-
Scotts EZ Patch Repair Mix
Every lawn eventually develops a few bald spots from foot traffic or heat. This repair mix acts like a bandage, combining mulch and fertilizer to help grass fill in those gaps quickly.
It is designed specifically for small areas rather than broad application. This is a must-have for targeted maintenance when you notice the lawn wearing thin in high-traffic zones.
- Brand Name:Scotts
- Product Type:Repair Mix
- Weight Capacity:3.75 lbs
- Primary Benefit:Patch repair
- Target Grass:St. Augustine
- Additional Feature:Two pack convenience
- Additional Feature:Covers 170 square feet
- Additional Feature:Simplifies lawn repair
Frequently Asked Questions
How often should I fertilize St. Augustine grass?
You should feed your lawn during the active growing season, typically from late spring through early autumn. Depending on your location, this usually means 3 to 5 applications per year. Avoid fertilizing while the grass is dormant in the winter. Feeding during this time wastes money and can weaken the root system.
Will fertilizer kill my weeds?
Most standard fertilizers only provide nutrients and will not eliminate weeds. You must purchase a weed and feed product if you want to tackle both issues at once. Even then, these products usually only target broadleaf weeds. You may still need a separate treatment for stubborn grassy weeds like crabgrass.
Can I fertilize right after mowing?
It is better to fertilize the day after you mow rather than immediately following a cut. This gives the grass blades a chance to heal and prevents the granules from getting stuck in the freshly cut tips. Always check that your lawn is dry before applying granular products. Moisture on the blades can cause the fertilizer to stick and potentially burn the foliage.
Do I need to water after applying fertilizer?
Yes, watering is essential to wash the nutrients off the blades and into the soil where the roots can access them. A light irrigation of about quarter-inch of water is usually sufficient. Think of this step as activating the product. Without water, the fertilizer simply sits on the surface, where it is ineffective and prone to being washed away by rain.
What do the three numbers on the bag mean?
Those numbers represent the NPK ratio, which stands for nitrogen, phosphorus, and potassium. Nitrogen supports leaf growth, phosphorus helps root development, and potassium improves overall stress resistance. St. Augustine prefers a ratio that favors nitrogen to keep it lush and thick. Always verify these numbers on the front of the bag before making your purchase.
James Wilson is a seasoned product review specialist with a strong focus on coffee grinders and home brewing equipment. With years of hands-on experience testing both manual and electric grinders, he brings practical insights and honest recommendations to help readers make informed decisions. James is passionate about the role grind quality plays in achieving the perfect cup of coffee, and he combines technical knowledge with a user-friendly approach. His reviews are known for their clarity, depth, and reliability, making him a trusted voice for coffee enthusiasts looking to upgrade their daily brewing experience.
