St. Augustine grass is essentially a thirsty diva that demands specific nutrients to maintain its rich, dark carpet of green throughout the heat of July. Providing the wrong ratio of nitrogen can lead to excessive growth that invites disease, so precision is your best friend when selecting the Best Summer Fertilizers for St Augustine Grass.
Consistency remains the core pillar of a lush lawn. Choosing products that prioritize slow-release nitrogen will keep your yard healthy without burning the blades during those scorching afternoon temperatures. Read on to discover how these choices can keep your turf looking its best all season long.
Key Takeaways
- Prioritize formulas with high nitrogen levels to support the rapid blade development required by St. Augustine during its peak growth phase.
- Select slow-release nitrogen sources to prevent rapid, succulent growth that often attracts pests and promotes fungal infections.
- Inspect the label for the NPK ratio, ensuring the phosphorus content is kept low to meet specific soil requirements for established turf.
- Consider liquid applications if you need a rapid, short-term green-up for an upcoming event or a visible boost in color.
- Always check for added insecticides if you struggle with chinch bugs, as these pests love to feast on St. Augustine during dry summer stretches.
| Best All-Rounder |  |
Sunniland St. Augustine Weed and Feed | Combines feeding with weeding | Specifically formulated for St. Augustine | Good for basic maintenance | View on Amazon | Read Review |
| Reliable Nutrient Boost |  |
Simple Lawn Solutions Balanced 16-4-8 Liquid | Fast nutrient absorption | Easy to store bottle | Versatile across grass types | View on Amazon | Read Review |
| Dual Purpose Defender |  |
Scotts Turf Builder SummerGuard Insect Control | Kills surface insects | Promotes dense grass growth | Helps survive heat stress | View on Amazon | Read Review |
| Rapid Greening Agent |  |
Liquid St. Augustine Grass Fertilizer | Promotes deep green color | Supports new runner growth | Fast acting liquid | View on Amazon | Read Review |
| Heavy Duty Feeding |  |
SeedRanch St. Augustine Granular Fertilizer | Large capacity bag | High nitrogen content | Long lasting nutrition | View on Amazon | Read Review |
| Standard Maintenance Staple |  |
Scotts Turf Builder Lawn Food | Reliable growth results | Easy to use granules | Works on many grass types | View on Amazon | Read Review |
| Eco-Conscious Choice |  |
Sunniland St. Augustine Phosphorus Free | Phosphorus free formula | Slow release nitrogen | Environmentally responsible | View on Amazon | Read Review |
| Iron Rich Formula |  |
Fertilome Centipede and St. Augustine Fertilizer | High iron for color | Slow release nitrogen | Specifically for warm-season grass | View on Amazon | Read Review |
| Root Vigor Builder |  |
Simple Lawn Solutions 3-18-18 Liquid | Increases root vigor | Improves lawn hardiness | Easy spray application | View on Amazon | Read Review |
| Summer Growth Accelerator |  |
Maximum Green High Nitrogen Spray | Very high nitrogen | Attached hose sprayer | Quick color improvement | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed and Feed
If you want a straightforward solution for a lawn that needs both nutrients and a defensive edge, this is your primary choice. It handles weeds while feeding the grass, which saves you from performing two separate chores on a Saturday morning.
The formula is designed specifically for St. Augustine turf, so you do not have to worry about the typical sensitivities this grass variety shows to harsher, generic chemicals. Just keep in mind that this product is strictly for lawns, so avoid letting the dust drift onto your flower beds.
- Brand Name:Sunniland
- Coverage Area:5000 sq ft
- Additional Feature:Kills common lawn weeds
- Additional Feature:Sustains healthy grass growth
- Additional Feature:Simple application process
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Simple Lawn Solutions Balanced 16-4-8 Liquid
Sometimes your lawn just looks a bit tired and needs a quick infusion of energy to get back on track. This balanced liquid spray works well because it provides a steady mix of nitrogen, phosphorus, and potassium that hits the roots immediately.
Because it is a concentrated spray, you can apply it exactly where the grass looks thin. It is quite versatile, though you will need to ensure you have a standard garden hose attachment ready for the application.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:16-4-8
- Application Type:Liquid spray
- Package Weight:32 Ounce
- Additional Feature:High quality nutrient balance
- Additional Feature:Suitable for spring and summer
- Additional Feature:Concentrated for easy mixing
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Scotts Turf Builder SummerGuard Insect Control
Summer heat often brings out the insects that love to snack on your lawn as much as they love to annoy you. This product serves as a protective shield by feeding the grass while simultaneously keeping pests away from your soil.
It acts like a security guard for your yard, keeping the blades green while deterring invaders that cause brown spots. One limitation is that you must water it in thoroughly to ensure the insect-killing ingredients actually reach the root zone.
- Brand Name:Scotts
- Package Weight:13.35 lbs
- Coverage Area:5,000 sq ft
- Additional Feature:Prevents summer lawn damage
- Additional Feature:Easy to spread granules
- Additional Feature:Strengthens roots
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Liquid St. Augustine Grass Fertilizer
When you notice your lawn losing its luster, this high nitrogen liquid can bring back that deep, dark green color quite fast. It is a focused liquid food that encourages the plant to spread out through new runners, which is perfect if you are trying to fill in some bare patches.
Because it is a liquid, it offers fast nutrient delivery directly to the blades. Just remember that because it is so potent, you should be careful not to apply it during the hottest part of the day to avoid leaf burn.
- Brand Name:Generic
- Formula Ratio:High Nitrogen
- Application Type:Liquid
- Package Weight:8 oz
- Additional Feature:Easy to mix
- Additional Feature:Encourages thick growth
- Additional Feature:Direct root support
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SeedRanch St. Augustine Granular Fertilizer
For those who have a larger lawn and prefer a granular approach, this 50-pound bag is a sturdy choice. It delivers a heavy dose of nitrogen which is exactly what St. Augustine grass craves to produce those thick, carpet-like blades.
It is a no-nonsense fertilizer that provides the nutrition needed for a high-traffic lawn. The downside is that the large bag is heavy, so ensure you have a broadcast spreader ready to make the work easier on your back.
- Brand Name:SeedRanch
- Formula Ratio:24-2-11
- Package Weight:50 lbs
- Additional Feature:Perfect for large lawns
- Additional Feature:Promotes lush growth
- Additional Feature:Professional grade formula
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Scotts Turf Builder Lawn Food
If you want something that you can pick up anywhere and trust to do the job, this is the classic choice for general lawn health. It provides a steady release of nutrients that keeps your grass growing strong without requiring a degree in chemistry.
It is like a dependable multivitamin for your soil that works reliably throughout the summer months. While it is excellent for maintenance, it does not have the specialized pest or weed control that some other options offer.
- Brand Name:Scotts
- Package Weight:12.5 lbs
- Coverage Area:5,000 sq ft
- Additional Feature:Consistent nutrient release
- Additional Feature:Simple application
- Additional Feature:Widely available
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Sunniland St. Augustine Phosphorus Free
Many regions have regulations regarding the use of phosphorus in lawn care, and this phosphorus-free formula keeps you compliant while still feeding your grass. It uses slow-release nitrogen, which means your lawn gets a steady meal instead of a quick sugar rush that fades away.
It is an ideal option for maintaining thick, vibrant turf without unnecessary additives. One thing to keep in mind is that the slow-release nature means you won't see results overnight, but the long-term health of your soil will benefit.
- Brand Name:Sunniland
- Formula Ratio:20-0-6
- Package Weight:20 lb bags
- Coverage Area:5,000 sq ft per bag
- Additional Feature:Professional quality ingredients
- Additional Feature:Sustained feeding cycle
- Additional Feature:Prevents runoff issues
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Fertilome Centipede and St. Augustine Fertilizer
This fertilizer is a bit of a secret weapon because it contains high iron content alongside the nitrogen, which helps keep your grass from yellowing. It is specifically balanced to support the metabolic needs of warm-season grasses like St. Augustine.
Think of the iron as an extra polish for your lawn color. It works as a slow-release product, so it is quite gentle on the roots, though you should always follow the bag instructions carefully to avoid over-applying.
- Brand Name:Fertilome
- Formula Ratio:15-0-15
- Package Weight:16 lbs
- Additional Feature:Prevents grass yellowing
- Additional Feature:Steady growth support
- Additional Feature:Professional results
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Simple Lawn Solutions 3-18-18 Liquid
While most fertilizers focus on height and color, this liquid spray prioritizes root health and hardiness. By providing a higher concentration of phosphorus and potassium, it prepares your lawn to handle the stress of late summer heat and early fall cooling.
It acts like a foundation strengthener for a house, ensuring that the base of your lawn is as strong as the blades. Just note that this is not meant for rapid greening, so use it alongside your nitrogen-based products.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:3-18-18
- Application Type:Liquid spray
- Package Weight:32 Ounce
- Additional Feature:Concentrated formula
- Additional Feature:Simple to use
- Additional Feature:Supports plant resilience
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Maximum Green High Nitrogen Spray
When the summer heat is at its peak and you want your lawn to stay ahead of the game, this high nitrogen liquid is your best bet. It comes with an attached sprayer, which makes the process of feeding your lawn almost as quick as walking across the yard.
It is perfect for those who want a massive color improvement in a short amount of time. Since it is very concentrated, be very sure to follow the dilution instructions on the bottle to keep your lawn happy and safe.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:28-0-0
- Application Type:Liquid spray
- Package Weight:32 Ounce
- Additional Feature:Fast and slow release
- Additional Feature:Convenient application
- Additional Feature:Professional lawn food
Frequently Asked Questions
How often should I fertilize my St. Augustine grass in the summer?
You should aim to fertilize every six to eight weeks during the active growing season. Do not push the schedule, as over-fertilizing can lead to excessive thatch buildup and disease.
Will fertilizing cause my lawn to brown during a heatwave?
High nitrogen levels during extreme heat can cause fertilizer burn. If the forecast shows a heatwave, wait for cooler temperatures or make sure you provide plenty of water immediately after application to push the nutrients into the soil.
Is it better to apply fertilizer in the morning or evening?
Always apply your fertilizer in the early morning when the grass is dry but the air is still cool. You want to avoid the heat of the day, which can cause the granules to sit on the blades and create unsightly brown spots.
Do I need to water the lawn after fertilizing?
Yes, watering is essential to activate the fertilizer and move it into the root zone. Aim for about one quarter inch of water shortly after you finish spreading the product.
Can I use the same fertilizer for St. Augustine as I do for Bermuda grass?
You should avoid doing this because these grasses have different nutritional requirements. St. Augustine is more sensitive to certain herbicides and potassium needs, so always look for a label that specifically mentions it is safe for St. Augustine.
