The morning dew is still clinging to the blades as you walk across the lawn. You can see those yellowing patches starting to pop up where the heat is hitting hardest. It is time to intervene before the drought sets in for good.
Keeping your turf thick and dark despite the scorching sun requires a clear strategy. Finding the Best Summer Fertilizers for St Augustine Grass is the difference between a lawn that thrives and one that slowly fades away. Let us break down the specifics to help you pick the right bag or bottle for your yard.
Key Takeaways
- Prioritize formulas with slow release nitrogen to ensure your grass gets a steady stream of nutrients over several weeks rather than a quick, unsustainable burst.
- Check the NPK ratio carefully to ensure you provide enough nitrogen for leaf growth without overloading the soil with phosphorus if your local regulations restrict it.
- Choose liquid fertilizers if you want fast absorption through the leaves, which is often helpful when the soil is too dry or compacted for granular types.
- Select a weed and feed option only if you have active weed growth, because applying broad-spectrum herbicides in peak heat can sometimes stress sensitive grass types.
- Look for added iron in the ingredient list if you want to achieve that deep, dark green color without forcing excess growth during the hottest parts of the year.
| Best Overall Maintenance |  |
Sunniland St. Augustine Weed and Feed | Combines weed control and nutrition | Tailored for St. Augustine | Effective for 5,000 square feet | View on Amazon | Read Review |
| Top Pest Defense |  |
Scotts Turf Builder SummerGuard Insect Control | Dual action feeding and protection | Kills common lawn insects | Promotes steady summer growth | View on Amazon | Read Review |
| Ideal Liquid Nourishment |  |
Simple Lawn Solutions Balanced Liquid Fertilizer | Quick nutrient absorption | Easy to mix formula | Balanced NPK ratio | View on Amazon | Read Review |
| Growth Booster Specialist |  |
St. Augustine Liquid Grass Food | Promotes new grass runners | Increases color intensity | Supports root development | View on Amazon | Read Review |
| Heavy Duty Feeding |  |
SeedRanch St. Augustine Granular Fertilizer | High nutrient concentration | Ideal for large lawns | Lasting nitrogen support | View on Amazon | Read Review |
| Reliable General Maintenance |  |
Scotts Turf Builder Lawn Food | Consistent growth results | Easy to find | Reliable brand quality | View on Amazon | Read Review |
| Sustainable Nutrient Release |  |
Sunniland St. Augustine Slow-Release Fertilizer | Slow release nitrogen | Phosphorus free | Professional balanced ratio | View on Amazon | Read Review |
| Strongest Root Builder |  |
Simple Lawn Solutions Root Vigor | Enhances root vigor | High potassium and phosphorus | Concentrated liquid spray | View on Amazon | Read Review |
| Deep Green Specialist |  |
Fertilome High Iron Fertilizer | High iron content | Slow release nitrogen | Deepens grass color | View on Amazon | Read Review |
| Rapid Greening Solution |  |
Maximum Green High Nitrogen Spray | Rapid greening effect | Easy hose attachment | High nitrogen boost | View on Amazon | Read Review |
More Details on Our Top Picks
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Sunniland St. Augustine Weed and Feed
If you want to clear out unwanted weeds while you feed your lawn, this is your primary choice. It is specifically formulated to address the unique needs of St. Augustine varieties without causing the stress that some stronger chemicals might trigger.
The formula helps you target invasive weeds while providing the nutrients your grass needs to thrive in the heat. Just keep in mind that you should avoid using this if your grass is already suffering from drought or extreme heat stress.
- Brand:Sunniland
- Coverage Area:5,000 square feet
- Application Method:Granular spread
- Additional Feature:Targeted weed elimination
- Additional Feature:St. Augustine specific formula
- Additional Feature:Consistent nutrient delivery
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Scotts Turf Builder SummerGuard Insect Control
Summer heat often invites unwanted pests to settle into your lawn, which is where this dual purpose product shines. By combining essential plant food with an insecticide, it protects your grass from common turf insects while encouraging a deep green color.
It acts as a shield, allowing your grass to focus energy on growth rather than recovering from insect damage. Be aware that this is not meant for heavy weed infestations, so keep your expectations focused on insect prevention and general health.
- Brand:Scotts
- Coverage Area:5,000 square feet
- Container Size:13.35 lbs
- Additional Feature:Built in insect killer
- Additional Feature:Strengthens roots against stress
- Additional Feature:Improves overall density
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Simple Lawn Solutions Balanced Liquid Fertilizer
When you want a quick fix, reach for this liquid 16-4-8 formula. It delivers nutrients directly to the blades for faster absorption, which is incredibly helpful when your lawn looks a bit tired mid-summer.
The balanced ratio provides a steady supply of nutrients that helps the grass maintain its vigor. Since it is a concentrate, you will need a hose end sprayer to apply it effectively across your yard.
- Brand:Simple Lawn Solutions
- Formulation:16-4-8 Liquid
- Container Size:32 Ounce
- Additional Feature:High quality liquid nutrients
- Additional Feature:Fast acting formula
- Additional Feature:Suitable for any grass
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St. Augustine Liquid Grass Food
If your lawn has bare spots or is spreading slowly, this high nitrogen liquid is a smart pick. It is designed to encourage new runners, which helps your grass fill in thin areas effectively during the peak of summer.
You get a concentrated dose of nutrients that promotes a vibrant color and supports overall root health. Since the bottle is smaller, this is best suited for spot treatments or smaller lawn sections.
- Brand:Generic/Specialized
- Formulation:High Nitrogen Liquid
- Container Size:8 Ounce
- Additional Feature:Fast nutrient delivery
- Additional Feature:Easy mix and feed
- Additional Feature:Encourages thicker growth
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SeedRanch St. Augustine Granular Fertilizer
For larger lawns that need a serious boost, this 50-pound bag offers a high-performance 24-2-11 ratio. It is a workhorse that provides the heavy nitrogen your grass requires to stay lush when the temperature climbs.
You will appreciate the long-lasting results this granular formula provides throughout the season. Because of the large bag size, it is definitely better suited for homeowners with larger lots rather than small patches.
- Brand:SeedRanch
- Formulation:24-2-11 Granular
- Container Size:50 lbs
- Additional Feature:Professional grade strength
- Additional Feature:Promotes rapid greening
- Additional Feature:Supports dense turf
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Scotts Turf Builder Lawn Food
You cannot go wrong with a classic, and this standard lawn food is a staple for a reason. It is designed to work across many grass types, providing a reliable feeding schedule that keeps your lawn resilient against the summer sun.
It is simple to apply with a standard spreader and gives the grass exactly what it needs to build stronger roots. Just note that this lacks the specialized insect or weed control features found in more specific formulas.
- Brand:Scotts
- Coverage Area:5,000 square feet
- Container Size:12.5 lbs
- Additional Feature:Improves overall grass health
- Additional Feature:Essential summer nutrients
- Additional Feature:Dependable granular texture
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Sunniland St. Augustine Slow-Release Fertilizer
Slow-release fertilizers are like a steady drip of caffeine for your lawn, keeping it energized for weeks without the sudden growth spurts. This phosphorus free formula is a smart way to feed your grass while being mindful of runoff.
The 20-0-6 ratio is specifically balanced to prevent over-feeding while maintaining a healthy, deep green look. You get two bags in this pack, making it a great value for those with larger properties.
- Brand:Sunniland
- Formulation:20-0-6 Granular
- Coverage Area:10,000 square feet (2 pack)
- Additional Feature:Environmentally conscious formula
- Additional Feature:Consistent feeding schedule
- Additional Feature:St. Augustine optimized
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Simple Lawn Solutions Root Vigor
Sometimes your lawn needs more than just green blades; it needs a solid foundation. This 3-18-18 formula focuses on the potassium and phosphorus levels required to build deep, strong roots that help your grass survive heat waves.
It is an excellent choice to use as a supplement during the later part of summer. Because it is so root-focused, do not expect immediate dark green color, but look for better resilience instead.
- Brand:Simple Lawn Solutions
- Formulation:3-18-18 Liquid
- Container Size:32 Ounce
- Additional Feature:Boosts turf hardiness
- Additional Feature:Easy spray application
- Additional Feature:Summer and fall support
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Fertilome High Iron Fertilizer
If your grass looks pale or yellow despite regular watering, it might be suffering from an iron deficiency. This high iron formula acts like a vitamin boost, turning your St. Augustine into a deep, dark green that is the envy of the street.
The 15-0-15 ratio provides a balanced nutrient profile that is gentle on your lawn while delivering quick visual results. It is highly effective for maintaining that "golf course" look throughout the summer.
- Brand:Fertilome
- Formulation:15-0-15 Granular
- Container Size:16 lbs
- Additional Feature:Corrects yellowing symptoms
- Additional Feature:Sustained release action
- Additional Feature:Warm season optimized
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Maximum Green High Nitrogen Spray
When you have an event coming up and want the lawn to look its absolute best, this high nitrogen liquid is your go-to. It is designed for maximum impact, delivering a quick hit of color that transforms the appearance of your grass in short order.
The attached sprayer makes application feel as simple as watering your garden. Keep in mind that because this is a quick-release formula, you will need to reapply more frequently than you would with granular options.
- Brand:Simple Lawn Solutions
- Formulation:28-0-0 Liquid
- Container Size:32 Ounce
- Additional Feature:Fast acting results
- Additional Feature:Simple spray nozzle
- Additional Feature:High concentration formula
Frequently Asked Questions
Should I fertilize my lawn if we are experiencing a drought?
Avoid fertilizing when the ground is bone dry. Fertilizer salts can draw moisture out of the roots, effectively dehydrating your grass even further. Wait until you have a forecast for rain or until you can provide a deep watering session to help the nutrients move into the soil.
Will a high nitrogen fertilizer kill my weeds?
No, nitrogen is food for everything, including weeds. If you have a heavy weed problem, you need a product that contains a post emergent herbicide specifically designed for St. Augustine. Just ensure the weather is below 85 degrees, or the herbicide might damage your turf.
How much fertilizer do I actually need to apply?
Follow the application rate printed on the bag strictly. Most St. Augustine lawns require about one pound of nitrogen per 1,000 square feet per application. Using too much fertilizer does not make the grass grow better, but it will significantly increase the risk of fertilizer burn.
Can I use the same fertilizer on my St. Augustine as I do on my shrubs?
It is better to use a dedicated turf fertilizer for the lawn. Shrubs often require different levels of phosphorus and micronutrients that might cause imbalanced growth in your grass. Keep the lawn food for the yard and buy a specialized product for your flower beds.
What should I do if my grass turns yellow after fertilizing?
Yellowing often happens if you apply fertilizer during a heat wave or if you miss a spot with the spreader. Make sure you are watering in the granules immediately after application to push them down into the soil. If the yellowing persists, check your soil pH or look for signs of iron deficiency.
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