Why is your lawn turning yellow despite all the rain? Florida heat is relentless, and St. Augustine grass requires a very specific diet to stay thick and vibrant against the humidity.
Finding the Best Fertilizers for St Augustine Grass in Florida is the difference between a lush carpet and a patch of weeds. Read on to see which formulas give your turf the nutrients it needs to thrive.
Key Takeaways
- Prioritize formulas with high potassium levels to help your grass resist the stress of high heat and drought.
- Choose a slow-release nitrogen source to ensure your lawn receives steady nutrition over several weeks instead of one quick burst.
- Always check the bag or bottle for the nitrogen to phosphorus to potassium ratio, as St. Augustine usually performs best with lower phosphorus levels.
- Consider your preferred application method, deciding whether you want the convenience of a hose-end liquid sprayer or the uniform coverage of granular pellets.
- Watch for added iron in your fertilizer mix, which provides that deep green color everyone wants without forcing excessive, weak growth.
| Best Overall Choice |  |
Sunniland St. Augustine Weed and Feed | Controls common lawn weeds | Formulated for St. Augustine | Easy application process | View on Amazon | Read Review |
| Fast Absorption Liquid |  |
Simple Lawn Solutions Balanced Liquid Fertilizer | High nutrient availability | Easy hose-end application | Promotes rapid greening | View on Amazon | Read Review |
| Growth Stimulating Formula |  |
St. Augustine High Nitrogen Liquid Food | Encourages new runners | Supports deep roots | Rapid nutrient delivery | View on Amazon | Read Review |
| Eco-Conscious Granular Option |  |
Sunniland Phosphorus Free Lawn Fertilizer | Phosphorus free formula | Slow release nitrogen | Large coverage area | View on Amazon | Read Review |
| Large Scale Coverage |  |
SeedRanch St. Augustine Heavy Duty Fertilizer | High nutrient concentration | Bulk bag size | Promotes healthy blades | View on Amazon | Read Review |
| Reliable Household Staple |  |
Scotts Turf Builder Lawn Food | Consistent performance | Easy to find | Reliable nutrient blend | View on Amazon | Read Review |
| Instant Color Booster |  |
Scotts Liquid Green Max Food | Added iron content | Rapid visual results | Convenient liquid format | View on Amazon | Read Review |
| Dual Purpose Defender |  |
Scotts SummerGuard Insect Control Fertilizer | Includes insect control | Feeds and protects | Convenient application | View on Amazon | Read Review |
| Nutrient Dense Supplement |  |
Superior Nitrogen and Potassium Liquid Feed | Includes organic additives | Easy attached sprayer | Improves soil health | View on Amazon | Read Review |
| High Iron Specialty |  |
Fertilome Slow Release Iron Fertilizer | High iron content | Slow release nitrogen | Corrects yellowing blades | 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 Florida lawn, this is your go-to. It combines essential nutrients with weed control, which saves you from having to do two jobs at once.
It works specifically for the unique needs of St. Augustine grass. Just keep in mind that since it contains herbicide, you must use it carefully near your prized flower beds.
- Brand Name:Sunniland
- Product Type:Granular Weed and Feed
- Coverage Area:5000 square feet
- Additional Feature:Dual action formula
- Additional Feature:Convenient granular form
- Additional Feature:Targeted weed suppression
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Simple Lawn Solutions Balanced Liquid Fertilizer
You will appreciate this liquid option if you want to see a quick color change in your lawn. The 16-4-8 ratio provides a balanced meal that helps the grass recover from the stress of a hot Florida summer.
Because it is a spray, it acts like a vitamin shot for your soil. It is not meant to replace your long-term granular program, but it acts as a perfect supplement when growth stalls.
- Brand Name:Simple Lawn Solutions
- Product Type:Liquid Fertilizer
- Weight Or Volume:32 Ounce
- NPK Ratio:16-4-8
- Additional Feature:Concentrated spray formula
- Additional Feature:Suitable for all grasses
- Additional Feature:Ideal for summer use
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St. Augustine High Nitrogen Liquid Food
This liquid food focuses on thicker growth and those essential new runners that fill in bare spots. The high nitrogen content acts like a kickstart for your lawn during the active growing season.
It is an easy mix solution that delivers nutrients directly where the plant needs them most. Avoid applying this during the dead of winter when the grass is resting.
- Brand Name:Unbranded/Generic
- Product Type:Liquid Fertilizer
- Weight Or Volume:1 Gallon
- Additional Feature:High nitrogen content
- Additional Feature:Simple to mix
- Additional Feature:Enhances green color
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Sunniland Phosphorus Free Lawn Fertilizer
Many Florida soils already have plenty of phosphorus, so this phosphorus free blend is a smart pick to stay environmentally responsible. It uses slow-release nitrogen to feed your lawn steadily over several weeks.
You get a consistent supply of food without the risk of a growth spike that might stress the grass. This is a solid, reliable workhorse for routine maintenance.
- Brand Name:Sunniland
- Product Type:Granular Fertilizer
- Weight Or Volume:20 lb Bags
- NPK Ratio:20-0-6
- Coverage Area:5000 square feet per bag
- Additional Feature:Professional grade granular
- Additional Feature:Consistent feeding schedule
- Additional Feature:Specifically for St. Augustine
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SeedRanch St. Augustine Heavy Duty Fertilizer
When you have a major project or a particularly large lawn, this 50-pound bag is the most efficient way to go. The 24-2-11 ratio provides a heavy dose of nitrogen and potassium, which are the two most critical elements for Florida turf.
You are getting a commercial strength product that is designed for longevity. Make sure you have a quality spreader to ensure you get an even distribution across the entire yard.
- Brand Name:SeedRanch
- Product Type:Granular Fertilizer
- Weight Or Volume:50 lbs
- NPK Ratio:24-2-11
- Additional Feature:Professional strength formula
- Additional Feature:Sustained feeding cycle
- Additional Feature:Supports thick turf
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Scotts Turf Builder Lawn Food
Sometimes you just want a trusted name that works reliably every single time. This is a classic granular food that helps your grass build up its natural defenses against the humidity and heat found in Florida.
It is simple to use and widely available at most local hardware stores. Just be sure to water it in well after application to prevent any burn on the leaf tips.
- Brand Name:Scotts
- Product Type:Granular Fertilizer
- Weight Or Volume:12.5 lbs
- Coverage Area:5000 square feet
- Additional Feature:All grass types
- Additional Feature:Balanced growth support
- Additional Feature:Well-known formulation
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Scotts Liquid Green Max Food
This product doubles as a two-in-one supplement by adding iron alongside the primary fertilizer. If your lawn looks dull or pale, the iron provides that deep, dark green look that makes the neighbors jealous.
The liquid delivery means you will see a noticeable difference within a few days. It is not a complete replacement for a full feeding program, but it is excellent for a quick touch-up.
- Brand Name:Scotts
- Product Type:Liquid Fertilizer
- Weight Or Volume:32 oz
- Additional Feature:2-in-1 iron supplement
- Additional Feature:Easy hose attachment
- Additional Feature:Fast-acting nutrients
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Scotts SummerGuard Insect Control Fertilizer
Summer in Florida often brings both heat and hungry bugs, so this all-in-one product handles both issues at once. It feeds your grass while providing a protective barrier against common lawn insects.
Using this is a smart time-saver when the pressure from pests is at its peak. Do not use it as a preventative measure for extended periods, but rather as a tactical strike when you see insect activity.
- Brand Name:Scotts
- Product Type:Fertilizer and Insecticide
- Weight Or Volume:13.35 lbs
- Coverage Area:5000 square feet
- Additional Feature:Summer stress support
- Additional Feature:Targeted pest reduction
- Additional Feature:Turf builder nutrients
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Superior Nitrogen and Potassium Liquid Feed
This liquid mix stands out because it includes humic acid, fish, and seaweed in addition to the standard nitrogen and potassium. These organic additives act like a probiotic for your soil, improving its ability to hold nutrients.
You get an attached sprayer with the bottle, making the application process completely painless. It is an excellent choice for a mid-season boost to keep the soil biology active and healthy.
- Brand Name:Simple Lawn Solutions
- Product Type:Liquid Fertilizer
- Weight Or Volume:32 Ounce
- NPK Ratio:15-0-15
- Additional Feature:Humic acid boost
- Additional Feature:Fish and seaweed blend
- Additional Feature:All season utility
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Fertilome Slow Release Iron Fertilizer
If your St. Augustine grass tends to yellow due to high soil pH, the high iron content in this bag is exactly what you need. It uses a slow-release nitrogen formula that provides a steady, controlled rate of growth.
It is designed to be gentle on the lawn while delivering long-lasting results. This is a professional-grade bag that requires a bit more care during application to ensure you hit your target area.
- Brand Name:Fertilome
- Product Type:Granular Fertilizer
- Weight Or Volume:16 lbs
- NPK Ratio:15-0-15
- Additional Feature:Professional grade iron
- Additional Feature:Controlled growth rate
- Additional Feature:Suitable for warm seasons
Frequently Asked Questions
How often should I fertilize my St. Augustine lawn?
You should aim to feed your lawn roughly four times per year during the active growing season. Space your applications about eight to ten weeks apart to keep the grass healthy and thick.
Will fertilizer kill my weeds?
Most standard fertilizers do not kill weeds, though some bags labeled as weed and feed contain selective herbicides. Be very careful with these, as St. Augustine grass is sensitive to many chemicals that kill common broadleaf weeds.
Should I water the lawn after applying fertilizer?
Yes, watering is essential to help the nutrients move down into the soil where the roots can reach them. Aim for about one quarter inch of water shortly after spreading the granules to avoid burning the leaf blades.
Why does my grass turn brown after I fertilize?
This usually happens if you apply too much product at once, which creates a salt buildup that dehydrates the plant. Always follow the specific application rate on the bag to avoid this accidental burning.
Can I use the same fertilizer for my flower beds?
It is generally better to use a dedicated flower or vegetable fertilizer for your garden beds. Turf fertilizers are formulated specifically for leafy growth, whereas garden plants usually require different nutrient ratios to support blooms and fruit production.
