St. Augustine grass is a demanding host. It craves specific nutrient ratios and reacts poorly to harsh chemicals that might work fine on other turf.
Choosing the Best Lawn Fertilizers for St Augustine Grass means balancing immediate greening with long-term root health. One wrong move can leave your yard scorched rather than lush. Here is how to find the right fuel for your specific soil conditions.
Key Takeaways
- Prioritize slow-release nitrogen formulas to provide consistent growth without causing excessive, weak blade development.
- Always check for phosphorus-free labels if your local regulations or soil tests indicate high levels of existing nutrients.
- Match your application method, whether liquid spray or granular spread, to the size and density of your lawn area.
- Select products with added iron if your primary goal is achieving a deep, dark color without triggering a growth spurt.
- Confirm whether the product includes pre-emergent weed control to prevent unwanted plants from establishing alongside your grass.
| Best All-Around Choice |  |
Sunniland St. Augustine Weed and Feed | Controls common lawn weeds | Feeds established turf | Specifically for St. Augustine | View on Amazon | Read Review |
| Superior Nitrogen Source |  |
Sunniland 20-0-6 St. Augustine Fertilizer | Phosphorus free | Slow release nitrogen | Steady nutrient delivery | View on Amazon | Read Review |
| Rapid Nutrient Delivery |  |
Simple Lawn Solutions Balanced Liquid Fertilizer | Fast acting liquid | Easy to mix | Balanced nutritional profile | View on Amazon | Read Review |
| Growth Promoting Booster |  |
St. Augustine High Nitrogen Liquid Food | High nitrogen concentration | Encourages runner spread | Rapid nutrient absorption | View on Amazon | Read Review |
| Reliable Maintenance Staple |  |
Scotts Turf Builder Lawn Food | Consistent quality | Easy to find | All-purpose nutrient blend | View on Amazon | Read Review |
| Effective Weed Eradicator |  |
Scotts Turf Builder Weed and Feed | Kills common weeds | Feeds the lawn | Easy spreader application | View on Amazon | Read Review |
| Dual Action Shield |  |
Scotts SummerGuard Lawn Food | Kills lawn insects | Provides essential nutrients | Heat-season protection | View on Amazon | Read Review |
| Low Maintenance Solution |  |
Pennington Full Season Lawn Fertilizer | Single application convenience | Slow release formula | High nitrogen levels | View on Amazon | Read Review |
| Iron-Rich Color Booster |  |
Scotts Liquid Green Max | Immediate greening effect | High iron content | Easy hose attachment | View on Amazon | Read Review |
| Large Scale Professional |  |
SeedRanch St. Augustine Lawn Fertilizer | High volume capacity | Potassium-rich for health | Professional grade blend | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed and Feed
This is the go-to option if your lawn faces a dual threat of invasive weeds and nutrient deficiency. It acts like a targeted strike, feeding your grass while simultaneously suppressing unwanted invaders that compete for resources.
Expect steady growth without the shock of an immediate, rapid surge. It is designed specifically for the unique needs of St. Augustine grass, ensuring the soil chemistry stays balanced for your specific turf type. Just keep in mind that you must time your watering carefully to prevent runoff.
- Brand Name:Sunniland
- Product Type:Weed and Feed
- Application Method:Granular
- Total Coverage:5,000 sq ft
- Additional Feature:Dual action formula
- Additional Feature:Easy to spread
- Additional Feature:Promotes thick turf
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Sunniland 20-0-6 St. Augustine Fertilizer
If you want to push your lawn toward a deep, rich green without the worry of phosphorus runoff, this slow-release formula is your best bet. It provides a measured feeding schedule that prevents the grass from "greening up" too fast and then burning out.
The composition relies on a 20-0-6 ratio, which is ideal for maintaining turf health throughout the active growing season. Because it lacks phosphorus, it is a cleaner choice for lawns located near water sources or sensitive drainage areas. Be prepared to spread this over a slightly larger area since it comes in a two-pack bundle.
- Brand Name:Sunniland
- Product Type:Granular fertilizer
- Nutrient Ratio:20-0-6
- Application Method:Granular
- Total Coverage:10,000 sq ft
- Additional Feature:Consistent growth patterns
- Additional Feature:Environmentally conscious composition
- Additional Feature:Long lasting nutrition
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Simple Lawn Solutions Balanced Liquid Fertilizer
Liquid applications are like a vitamin shot for your grass, bypassing the soil to deliver nutrients directly to the blades. This balanced 16-4-8 blend is perfect if your lawn looks tired and needs a quick, visible boost during the peak of summer.
Because it is concentrated, you get a high degree of control over the application density. It works well on any grass type, though St. Augustine owners appreciate the fast absorption rate when the heat makes granular products slow to break down. You will need a hose-end sprayer to apply this effectively.
- Brand Name:Simple Lawn Solutions
- Product Type:Liquid fertilizer
- Nutrient Ratio:16-4-8
- Application Method:Hose-end spray
- Additional Feature:Concentrated formula
- Additional Feature:Quick greening results
- Additional Feature:Versatile application
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St. Augustine High Nitrogen Liquid Food
This liquid formula focuses on one thing: aggressive runner growth and lush, thick texture. If your lawn has thin patches or bare spots, this nitrogen-heavy mixture encourages the grass to spread rapidly to fill in those gaps.
It acts as a mechanical support system for root development, helping the turf anchor firmly into the soil. While it is perfect for spot treating or quick recovery, it is not a complete replacement for a full seasonal feeding program. Use it as a top-up treatment to keep the lawn looking dense.
- Brand Name:Generic/St. Augustine specialty
- Product Type:Liquid lawn food
- Application Method:Spray
- Additional Feature:Thickens sparse areas
- Additional Feature:Improves color vibrancy
- Additional Feature:Supports root systems
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Scotts Turf Builder Lawn Food
Scotts Turf Builder is a classic for a reason: it is the dependable workhorse of the lawn care industry. This granular food provides a broad range of nutrients that support general health, making it an excellent choice for a baseline seasonal routine.
It is designed to be safe for all grass types, including St. Augustine, when applied according to the bag instructions. While it doesn't offer specific weed or bug control, it is a solid foundation for consistent, healthy color. Just make sure to sweep any stray granules off your sidewalk to prevent staining.
- Brand Name:Scotts
- Product Type:Granular fertilizer
- Application Method:Granular
- Total Coverage:5,000 sq ft
- Additional Feature:Strengthens grass roots
- Additional Feature:Improves overall density
- Additional Feature:Simple spreader settings
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Scotts Turf Builder Weed and Feed
When dandelions and clover start to overtake your lawn, this product serves as a heavy-duty cleanup crew. It combines a potent weed killer with a steady feeding formula, allowing you to tackle two maintenance tasks in a single afternoon.
The granules cling to the leaves of existing weeds, ensuring the herbicide reaches the root and effectively kills the plant. It is designed to be tough on weeds while remaining gentle enough for established St. Augustine turf. Keep this away from your flower beds, as it is non-selective regarding garden plants.
- Brand Name:Scotts
- Product Type:Weed and Feed
- Application Method:Granular
- Total Coverage:5,000 sq ft
- Additional Feature:Clears out clover
- Additional Feature:Dandelion suppression
- Additional Feature:Builds stronger turf
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Scotts SummerGuard Lawn Food
Summer heat often brings out hungry insects that can ruin your lawn in a matter of weeks. This product acts like a protective umbrella, feeding your grass while simultaneously creating a barrier against common turf-destroying pests.
It is an ideal choice for the hottest months when you want to avoid multiple applications of different chemicals. By combining insect control and fertilizer, you save time and reduce the number of passes you need to make with your spreader. Be aware that it is formulated for specific seasonal timing, so follow the directions closely.
- Brand Name:Scotts
- Product Type:Fertilizer and insecticide
- Application Method:Granular
- Total Coverage:5,000 sq ft
- Additional Feature:Protects against grubs
- Additional Feature:Prevents heat stress
- Additional Feature:Simple seasonal application
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Pennington Full Season Lawn Fertilizer
If you are the type of person who prefers to do the job once and forget about it, this is your solution. The slow-release technology breaks down over the entire season, providing a steady drip of nutrients that prevents the common "feast or famine" growth cycle.
This is a high-nitrogen blend that excels at keeping St. Augustine grass thick and dark green without requiring bi-weekly attention. Because of the concentrated delivery, you only need one application to cover the core of the growing months. It is the ultimate choice for those who value efficiency.
- Brand Name:Pennington
- Product Type:Granular fertilizer
- Nutrient Ratio:32-0-5
- Application Method:Granular
- Total Coverage:4,000 sq ft
- Additional Feature:Lasts all season
- Additional Feature:Promotes deep greening
- Additional Feature:Consistent growth rate
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Scotts Liquid Green Max
Sometimes your grass isn't hungry for nitrogen, but it is starving for iron. This liquid 2-in-1 formula acts as a color intensifier, providing a deep, emerald hue that is often missing from lawns that look yellow or pale.
It is a great choice for quick improvements before a big event or simply to boost the curb appeal of your property. Since it is liquid, the results show up almost immediately compared to granular options. It serves as an excellent supplement to your primary fertilizer schedule rather than a replacement for it.
- Brand Name:Scotts
- Product Type:Liquid fertilizer/supplement
- Application Method:Hose-end spray
- Additional Feature:Enhances color quickly
- Additional Feature:Safe for all grasses
- Additional Feature:No mixing required
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SeedRanch St. Augustine Lawn Fertilizer
This is for the property owner with a significant amount of ground to cover. The professional-grade formula offers a nutrient ratio specifically tailored to the demanding needs of St. Augustine grass, ensuring that large lawns stay uniform and healthy.
The 24-2-11 ratio provides a healthy dose of potassium, which is critical for drought resistance and general hardiness. Since it comes in a 50-pound bag, it is designed for use with a broadcast spreader over substantial acreage. It cuts down on the need for frequent trips to the store for smaller bags.
- Brand Name:SeedRanch
- Product Type:Granular fertilizer
- Nutrient Ratio:24-2-11
- Application Method:Broadcast spreader
- Total Coverage:Large scale
- Additional Feature:Supports root strength
- Additional Feature:Ideal for large lawns
- Additional Feature:Consistent granule size
Frequently Asked Questions
How often should I fertilize my St. Augustine grass?
You should feed your lawn every 6 to 8 weeks during the active growing season. Start your first application in the spring only after the threat of frost has passed and the grass is actively greening up. Stop all nitrogen applications at least one month before your area's average first frost date.
Can I use a weed and feed product on new sod?
Avoid using weed and feed products on newly laid sod for at least 6 months. These chemicals are harsh and can inhibit the roots from establishing themselves in the underlying soil. Stick to a gentle, starter fertilizer with high phosphorus until the lawn is fully mature and knit together.
Why does my lawn turn yellow after fertilizing?
Yellowing often happens if you apply fertilizer during a drought or extreme heat. St. Augustine grass is sensitive to salt build-up from synthetic fertilizers when it is already under stress. Always water your lawn thoroughly immediately after application to push the nutrients into the root zone and prevent leaf burn.
Is phosphorus necessary for my grass?
Most established St. Augustine lawns do not require much phosphorus. In fact, excessive phosphorus can lead to runoff issues and may even hinder the plant's ability to absorb other micronutrients. Look for a low-phosphorus formula unless you are starting a new lawn from scratch.
Should I leave grass clippings on the lawn after fertilizing?
Yes, leaving your clippings behind is a smart way to recycle nutrients. These clippings act as a natural mulch that returns nitrogen and other minerals to the soil as they decompose. This practice can reduce your total fertilizer needs by up to 25 percent over the course of the year.
