Many homeowners grab the first bag of plant food they see on a store shelf without checking the NPK ratio. This oversight often leads to yellowing grass or stunted growth because St. Augustine is picky about its nutrients.
You need a strategy that matches your specific soil needs to maintain a thick, emerald carpet. Here is a breakdown of the Best St Augustine Fertilizers to help you make an informed decision for your lawn this season.
Key Takeaways
- Prioritize formulas that specify low or zero phosphorus content to protect local waterways and comply with regional environmental regulations.
- Choose slow-release nitrogen granular products if you want to feed your grass steadily over several months rather than pushing a quick, unsustainable growth spurt.
- Check the iron content in your fertilizer since St. Augustine grass requires frequent iron supplements to maintain that dark green color without forcing excessive blade elongation.
- Consider liquid options for faster nutrient absorption, especially if you need to correct a sudden yellowing issue within a few days.
- Match the bag weight or volume to your specific lawn square footage to avoid paying for excess product that will just sit in your shed.
| Professional Grade Nutrition |  |
SeedRanch St. Augustine 24-2-11 Fertilizer | High nitrogen concentration | Professional formulation | Large bag size | View on Amazon | Read Review |
| Fast Acting Green |  |
Liquid St. Augustine Lawn Food | Rapid nutrient absorption | Easy to mix | Encourages runner spread | View on Amazon | Read Review |
| Consistent Sustained Feeding |  |
Sunniland St. Augustine Slow Release Fertilizer | Slow release nitrogen | Phosphorus free | Two bag value pack | View on Amazon | Read Review |
| Iron Rich Supplement |  |
Fertilome St. Augustine Iron Fertilizer | High iron content | Slow release nitrogen | Gentle on grass | View on Amazon | Read Review |
| Reliable All Purpose |  |
Scotts Turf Builder Lawn Food | Easy to find | Reliable performance | Safe for all grasses | View on Amazon | Read Review |
| Seasonal Spray Specialist |  |
Simple Lawn Solutions Balanced Liquid | Balanced nutrient blend | Convenient spray bottle | Fast acting formula | View on Amazon | Read Review |
| Dual Action Defense |  |
BioAdvanced Weed and Feed | Feeds and weeds | Prevents new growth | Strengthens turf | View on Amazon | Read Review |
| Pest Fighting Nutrition |  |
Scotts SummerGuard Insect Control | Dual fertilizer and pesticide | Protects against insects | Improves lawn density | View on Amazon | Read Review |
| Iron Supplement Booster |  |
Scotts Liquid Green Max | Deepens green color | Fast visual results | Safe for all grasses | View on Amazon | Read Review |
| Bare Spot Fixer |  |
Scotts EZ Patch Repair | Includes mulch and fertilizer | Specifically for St. Augustine | Fixes bare patches | View on Amazon | Read Review |
More Details on Our Top Picks
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SeedRanch St. Augustine 24-2-11 Fertilizer
This is the heavy hitter for homeowners who want their lawn to look like a golf course. With a robust 24-2-11 nutrient ratio, it delivers the exact nitrogen kick your grass needs for rapid, vigorous growth.
It is best suited for those managing large plots who want to get the job done in one go. Just keep in mind that the 50-pound bag is heavy, so ensure you have a sturdy spreader ready for the application.
- Brand Name:SeedRanch
- Product Type:Granular fertilizer
- Nutrient Ratio:24-2-11
- Package Weight:50 lbs
- Additional Feature:Promotes rapid turf growth
- Additional Feature:Designed for warm-season grasses
- Additional Feature:Sustained release formula
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Liquid St. Augustine Lawn Food
If your lawn is looking a little tired or pale, this liquid concentrate is your best bet for a quick recovery. Because it is applied as a liquid, the nutrients bypass the soil surface and get right to the root zone for immediate uptake.
It works exceptionally well for promoting new runners, which helps fill in those thin patches. Be aware that liquid applications require more frequent attention than granular options since they do not stick around in the soil as long.
- Brand Name:Generic/White Label
- Product Type:Liquid concentrate
- Package Weight:1 Gallon
- Additional Feature:Supports thick growth
- Additional Feature:Enhances color quickly
- Additional Feature:Simple spray application
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Sunniland St. Augustine Slow Release Fertilizer
Sunniland provides a controlled release of nitrogen, which means your grass stays fed for weeks rather than having a short, frantic burst of growth. The phosphorus-free formula is a smart choice if you live near waterways or want to avoid unnecessary runoff.
This is a solid choice for the routine maintenance gardener who wants to keep things simple. You get two bags in the pack, covering a substantial 10,000 square feet total, making it an efficient use of your time.
- Brand Name:Sunniland
- Product Type:Granular fertilizer
- Nutrient Ratio:20-0-6
- Package Weight:20 lbs per bag
- Coverage Area:5,000 sq ft per bag
- Additional Feature:Consistent turf feeding
- Additional Feature:Safe for established lawns
- Additional Feature:Easy granular distribution
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Fertilome St. Augustine Iron Fertilizer
St. Augustine grass is famous for its love of iron, and this formula delivers a potent 15-0-15 boost. The high iron content acts like a multivitamin, turning yellowing grass into a deep, emerald green without forcing excessive, weak growth.
This is an excellent corrective measure for lawns suffering from micronutrient deficiencies. Since it uses slow-release nitrogen, it remains gentle on your grass during the hot summer months.
- Brand Name:Fertilome
- Product Type:Granular fertilizer
- Nutrient Ratio:15-0-15
- Package Weight:16 lbs
- Additional Feature:Corrects color deficiencies
- Additional Feature:Balanced nutrient profile
- Additional Feature:Suitable for warm seasons
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Scotts Turf Builder Lawn Food
Scotts is a household name for a reason, and this standard formula is a dependable baseline for almost any lawn. It contains a balanced blend that works well for all grass types, including St. Augustine, during the active growing season.
It is an ideal entry point for beginners who do not want to worry about complex chemical ratios. Just ensure you water the granules in thoroughly after application to prevent leaf burn and help the nutrients reach the soil.
- Brand Name:Scotts
- Product Type:Granular fertilizer
- Package Weight:12.5 lbs
- Coverage Area:5,000 sq ft
- Additional Feature:Improves overall lawn health
- Additional Feature:Consistent granule size
- Additional Feature:Simple application instructions
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Simple Lawn Solutions Balanced Liquid
This balanced liquid spray is perfect for mid-season touch-ups when your grass needs a little extra attention. The 16-4-8 ratio provides a great mix of macronutrients to keep the lawn growing steadily through the heat of the summer.
Because it comes in a spray bottle, it is incredibly easy to treat specific spots or smaller sections of the yard. It is a great companion product to have in the garage for when you notice areas that look a bit sluggish.
- Brand Name:Simple Lawn Solutions
- Product Type:Liquid fertilizer
- Nutrient Ratio:16-4-8
- Package Weight:32 oz
- Additional Feature:Perfect for spot treatment
- Additional Feature:Spring and summer use
- Additional Feature:Concentrated liquid formula
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BioAdvanced Weed and Feed
Weeds are the natural enemy of a healthy St. Augustine lawn, and this granular product tackles them while feeding your grass. It is a time-saving solution that kills existing weeds and prevents new ones from taking root.
Be very careful to apply this only when the weather is appropriate, as weed killers can stress grass if the temperature is too high. If you follow the instructions, you get a clean, thick lawn that does not have to compete with invaders.
- Brand Name:BioAdvanced
- Product Type:Granular weed and feed
- Package Weight:10 lbs
- Coverage Area:4,000 sq ft
- Additional Feature:Controls broadleaf weeds
- Additional Feature:Promotes dense growth
- Additional Feature:Southern lawn specific
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Scotts SummerGuard Insect Control
Summer heat often brings out pesky insects that chew on your grass blades. This product kills two birds with one stone by delivering both essential nutrients and an insecticide to keep your lawn protected.
It is best for those who live in humid climates where grubs or surface feeders are a common occurrence. Always remember that this is a preventative measure, so it works best before an infestation gets out of control.
- Brand Name:Scotts
- Product Type:Granular fertilizer with insecticide
- Package Weight:13.35 lbs
- Coverage Area:5,000 sq ft
- Additional Feature:Insect killing action
- Additional Feature:Promotes summer resilience
- Additional Feature:Easy spreader application
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Scotts Liquid Green Max
If you want that dark, vibrant color without the risk of over-fertilizing, this is your go-to. It is essentially an iron supplement that makes your lawn look healthy and lush within just a few days of application.
It is safe for any grass type and can be applied whenever you want a quick boost. Just keep in mind that this is primarily a color enhancer rather than a heavy-duty growth fertilizer, so it works best alongside your regular feeding schedule.
- Brand Name:Scotts
- Product Type:Liquid iron supplement
- Package Weight:32 oz
- Additional Feature:Two-in-one formula
- Additional Feature:Non-staining potential
- Additional Feature:Simple spray bottle
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Scotts EZ Patch Repair
Every lawn has those stubborn bare patches that refuse to grow grass. This patch mix includes fertilizer and mulch to create the perfect environment for new grass to take hold in those empty gaps.
It is designed specifically for the unique needs of St. Augustine, helping it spread and knit together with the surrounding turf. It is a small-scale solution, so buy a pack to keep on hand for targeted repairs throughout the season.
- Brand Name:Scotts
- Product Type:Lawn repair mix
- Package Weight:3.75 lbs (2 pack)
- Coverage Area:170 sq ft
- Additional Feature:Aids root establishment
- Additional Feature:Easy to spread
- Additional Feature:Promotes grass spread
Frequently Asked Questions
How often should I fertilize my St. Augustine lawn?
You should aim to feed your lawn every six to eight weeks during the active growing season. Start your first application once the grass has fully greened up in the spring and stop about a month before the first predicted frost.
Will this fertilizer kill my flowers or shrubs?
Most lawn fertilizers are designed specifically for turfgrass and may damage ornamental plants if you are not careful. Use a deflector shield on your spreader to keep the granules away from flower beds. If you accidentally spill some on your plants, rinse them off with water immediately.
Can I apply fertilizer right before it rains?
A light rain is actually helpful because it helps the nutrients wash into the soil where the roots can reach them. However, avoid fertilizing during a heavy downpour, as the water will likely wash the granules into the street or storm drain. You want the fertilizer to settle into the soil, not disappear into the gutter.
Why is my grass turning brown after I fertilized?
This usually happens because of over-application, which causes the grass to dehydrate and burn. Always follow the bag instructions for your specific spreader setting. If you suspect you applied too much, water the lawn heavily to flush the excess nutrients deeper into the ground.
Do I really need to water after fertilizing?
Yes, watering is a crucial step to prevent the fertilizer from sitting on the leaf blades where it can cause damage. Use about one-quarter inch of water to ensure the granules settle down into the thatch layer. This simple step ensures your lawn gets the full benefit of the product you just purchased.
