Many homeowners treat their lawn like a generic patch of green, buying whatever bag catches their eye at the hardware store. St. Augustine grass is a demanding cultivar that reacts poorly to universal mixes.
Choosing the Best St Augustine Grass Fertilizers requires a specific understanding of nitrogen and iron levels. Stick around to learn how to identify the right nutrients for your particular soil conditions.
Key Takeaways
- Prioritize formulas that specify a slow-release nitrogen content to prevent rapid top growth that leaves your roots weak.
- Check the phosphorus level, as many warm-season lawns thrive better with little or no phosphorus to prevent unwanted weed growth.
- Match the application method to your equipment, as liquid sprays provide faster green-up while granular options offer longer feeding intervals.
- Always verify the NPK ratio on the label, because a balanced 16-4-8 mix serves a different purpose than a heavy nitrogen 24-2-11 formula.
- Look for added micronutrients like iron and humic acid to help your grass maintain a deep, healthy color during the heat of summer.
| Best Overall Performer |  |
LESCO St. Augustine Weed and Feed | Controls broadleaf weeds efficiently | Provides essential nutrients | Professional grade formulation | View on Amazon | Read Review |
| Rapid Nutrient Delivery |  |
Liquid St. Augustine Lawn Food | Fast nutrient absorption | Encourages thick growth | Easy hose-end application | View on Amazon | Read Review |
| Versatile Seasonal Booster |  |
Simple Lawn Solutions Balanced Fertilizer | Balanced nutrient profile | Easy to store | Consistent lawn greening | View on Amazon | Read Review |
| Phosphorus Free Nutrition |  |
Sunniland St. Augustine Granular Fertilizer | Slow release nitrogen | Phosphorus free | Covers 5,000 square feet | View on Amazon | Read Review |
| Soil Health Optimizer |  |
Superior 15-0-15 Liquid Lawn Fertilizer | Includes beneficial humic acid | Contains organic additives | Convenient sprayer included | View on Amazon | Read Review |
| Reliable Household Standard |  |
Scotts Turf Builder Lawn Food | Easy to find | Thickens lawn density | Consistent pellet size | View on Amazon | Read Review |
| Targeted Weed Killer |  |
Scotts Turf Builder Weed Feed | Kills clover and dandelions | Dual action feeding | Simple application | View on Amazon | Read Review |
| Pests and Nutrition |  |
Scotts SummerGuard Insect Control | Controls lawn insects | Provides essential food | Easy application process | View on Amazon | Read Review |
| Deep Green Specialist |  |
Fertilome Iron Rich Fertilizer | High iron for color | Slow release nitrogen | Targeted for warm-season grass | View on Amazon | Read Review |
| High Growth Fertilizer |  |
SeedRanch St. Augustine Heavy Duty | Strong nitrogen boost | Large bag size | Rapid growth encouragement | View on Amazon | Read Review |
More Details on Our Top Picks
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LESCO St. Augustine Weed and Feed
If you want a heavy-duty solution for a lawn that is currently suffering from weed encroachment, this is your primary choice. It combines a potent fertilizer with Penoxsulam, an active ingredient designed specifically to target stubborn weeds while keeping your St. Augustine grass safe and growing.
This is a professional-grade formula that works best for larger lawns where you need to address growth and weed control in one pass. Be aware that because this contains a strong herbicide, you should follow the application instructions precisely to avoid damaging non-target garden plants nearby.
- Brand Name:LESCO
- Application Method:Granular spreader
- Total Weight:50 lbs
- Primary Function:Weed and feed
- Additional Feature:Contains Penoxsulam herbicide
- Additional Feature:Large bag size
- Additional Feature:Targets invasive broadleaf weeds
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Liquid St. Augustine Lawn Food
When your grass looks a bit tired or chlorotic, liquid fertilizers act like a quick energy boost. This formula excels at moving nutrients directly into the leaf tissue, which helps promote runners and a deep green color much faster than a standard granular product.
You will find this most useful if you prefer to hook a container up to your hose and walk the lawn. It is a high nitrogen formula, so make sure you do not over-apply it during the hottest parts of the summer when the grass might be heat-stressed.
- Brand Name:St. Augustine
- Application Method:Liquid sprayer
- Total Weight:1 gallon
- Primary Function:Growth and greening
- Additional Feature:Supports root development
- Additional Feature:Promotes new grass runners
- Additional Feature:Simple liquid mix
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Simple Lawn Solutions Balanced Fertilizer
A balanced 16-4-8 ratio provides a steady diet for your grass without pushing too much of one specific nutrient. This is an excellent choice for homeowners who want a predictable, reliable fertilizer for spring and summer maintenance.
Because it is a liquid, you gain the benefit of even coverage across your entire yard without worrying about missing spots common with granular spreaders. Just keep in mind that liquids generally require more frequent applications to maintain a consistent nutrient level throughout the growing season.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:16-4-8
- Application Method:Liquid spray
- Total Weight:32 ounces
- Primary Function:Seasonal maintenance
- Additional Feature:Concentrated formula
- Additional Feature:Safe for all grass types
- Additional Feature:Rapid uptake by plants
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Sunniland St. Augustine Granular Fertilizer
If you live in an area with strict environmental regulations regarding phosphorus runoff, this formula is a smart, responsible move. It focuses on slow release nitrogen, which ensures your lawn feeds consistently over several weeks rather than spiking growth all at once.
This is best for those who prefer the traditional granular approach and want to cover a large area with minimal effort. Since the bag is phosphorus-free, it helps maintain the health of your soil without adding unnecessary chemicals that could leach into local water tables.
- Brand Name:Sunniland
- Formula Ratio:20-0-6
- Application Method:Granular spreader
- Total Weight:40 lbs (2 pack)
- Coverage Area:5,000 sq ft
- Primary Function:Growth maintenance
- Additional Feature:Safe for local waterways
- Additional Feature:Consistent feeding cycle
- Additional Feature:Easy to spread pellets
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Superior 15-0-15 Liquid Lawn Fertilizer
This liquid fertilizer does more than just green up your grass; it includes humic acid, fish, and seaweed to improve the quality of your soil. It is a fantastic option if you want to support root growth and overall plant vigor rather than just forced blade height.
You get an attached sprayer with the bottle, which saves you from needing extra equipment. While it provides excellent micronutrients, you will need to reapply it more often than a heavy granular fertilizer to keep the results looking sharp.
- Brand Name:Simple Lawn Solutions
- Formula Ratio:15-0-15
- Application Method:Attached sprayer
- Total Weight:32 ounces
- Primary Function:Growth and health
- Additional Feature:Fish and seaweed base
- Additional Feature:All season formula
- Additional Feature:Improves soil structure
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Scotts Turf Builder Lawn Food
Sometimes you just need a dependable staple that works well on almost any lawn. This product is formulated to thicken your grass and keep it healthy throughout the peak growing season, making it a safe bet for most St. Augustine owners.
It is very straightforward to use with a standard broadcast spreader. The only potential downside is that it lacks the specific weed-fighting power of specialized formulas, so it is best used as a maintenance tool rather than a remedial one.
- Brand Name:Scotts
- Application Method:Granular spreader
- Total Weight:12.5 lbs
- Coverage Area:5,000 sq ft
- Primary Function:General growth
- Additional Feature:Works on all grass
- Additional Feature:Trusted industry formula
- Additional Feature:Consistent granule distribution
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Scotts Turf Builder Weed Feed
If you are tired of looking at clover and dandelions, this two-in-one product will do the heavy lifting for you. It combines a solid nitrogen boost for the grass with selective herbicides that kill common lawn weeds.
It is most effective when applied to a slightly damp lawn, as this helps the weed-killing granules stick to the leaves of the target plants. Keep in mind that you should avoid using this on newly seeded areas or sensitive ground covers to prevent unintended damage.
- Brand Name:Scotts
- Application Method:Granular spreader
- Total Weight:14.29 lbs
- Coverage Area:5,000 sq ft
- Primary Function:Weed and feed
- Additional Feature:Selective herbicide action
- Additional Feature:Thickens turf density
- Additional Feature:Fast acting granules
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Scotts SummerGuard Insect Control
Summer heat often brings out lawn-damaging insects, and this product handles them while keeping your grass fed. It is a dual-purpose solution designed to protect your lawn from bug infestations that might otherwise go unnoticed until the damage is already visible.
Use this if your lawn has a history of insect problems during the hotter months. It is not designed to kill weeds, so make sure you are choosing it for its protective properties rather than as a substitute for a standard weed and feed product.
- Brand Name:Scotts
- Application Method:Granular spreader
- Total Weight:13.35 lbs
- Coverage Area:5,000 sq ft
- Primary Function:Insect control
- Additional Feature:Protects against summer pests
- Additional Feature:Promotes steady growth
- Additional Feature:Reliable granular delivery
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Fertilome Iron Rich Fertilizer
The high iron content in this formula is the secret weapon for anyone who struggles with pale or yellowing St. Augustine grass. Iron provides that deep, dark green color that everyone wants without causing the grass to grow too fast and require constant mowing.
It works well for St. Augustine because it is tailored for warm-season grasses that need specific nutrient ratios to thrive in sandy or depleted soils. Since it uses slow-release nitrogen, your lawn will stay lush for a longer period between feedings.
- Brand Name:Fertilome
- Formula Ratio:15-0-15
- Application Method:Granular spreader
- Total Weight:16 lbs
- Primary Function:Greening and growth
- Additional Feature:Contains extra iron
- Additional Feature:Long lasting formula
- Additional Feature:Great for sandy soils
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SeedRanch St. Augustine Heavy Duty
This is a high-nitrogen powerhouse meant for people who want to see results quickly. With a 24-2-11 ratio, it packs enough punch to turn a struggling lawn around and fill in bare spots with new, vigorous runners.
Because it is a larger 50-pound bag, it is a cost-effective option for homeowners with very large properties to manage. Just be careful with the dosage, as the high nitrogen content can occasionally burn the grass if you apply it during a particularly dry or hot spell without enough water.
- Brand Name:SeedRanch
- Formula Ratio:24-2-11
- Application Method:Granular spreader
- Total Weight:50 lbs
- Primary Function:Rapid growth
- Additional Feature:High concentration of nutrients
- Additional Feature:Ideal for large lawns
- Additional Feature:Supports thick runner development
Frequently Asked Questions
How often should I fertilize my St. Augustine lawn?
You should aim to feed your lawn about four to five times per year during the active growing season. Start your first application once the grass has fully greened up in the spring, and stop at least a month before the first expected frost.
Will high nitrogen fertilizer burn my grass?
It certainly can if you apply too much at once or fail to water it in immediately. Always follow the application rate listed on the bag to the letter. Watering the lawn with about half an inch of water right after spreading the granules helps move the nutrients into the soil where they belong.
Can I use the same fertilizer for St. Augustine as I do for Bermuda grass?
You should be careful, as these grasses have very different requirements. Bermuda grass is much tougher and can handle higher concentrations of certain herbicides that would permanently damage St. Augustine. Always read the back of the bag to confirm the product is safe for your specific grass variety.
What is the best time of day to apply fertilizer?
The early morning is your best bet, especially if there is a bit of dew on the ground to help the granules settle. Avoid applying during the heat of the day, as this increases the risk of leaf burn. You also want to avoid applying right before a heavy rainstorm, which could wash your expensive fertilizer into the street drain instead of your yard.
Does the color of my fertilizer matter?
The color of the granules does not affect performance, but it can help you see where you have already walked. Some manufacturers dye their product to make it easier to track, which prevents you from accidentally overlapping and applying a double dose in one spot. Focus on the guaranteed analysis label instead of the appearance of the granules.
