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If you grow St. Augustine grass, the right fertilizer makes a big difference in color, density, and disease resistance. This guide focuses specifically on yard fertilizers formulated for St. Augustine grass and explains how nutrient ratios, release rates, and application timing affect real lawns. We shortlisted seven top options suited to common lawn situations and evaluated them against practical gardener concerns like feeding schedule and turf safety. Read on to understand what each fertilizing approach does in the yard and which product traits matter most for your patch of St. Augustine.
Top Picks at a Glance
| Best Overall The best all-around choice for most situations | The Andersons Professional PGF 16-0-8 Granular Lawn Fertilizer with Humic DG, 40 lb |  |
| Best Quality Built to a higher standard if you want something more solid | LESCO 50 lb. St. Augustine Grass Weed and Feed (Penoxsulam) |  |
| Best Value The sweet spot between price and what you get | The Andersons Professional PGF Complete 16-4-8 Granular Lawn Fertilizer (covers 5,000 sq ft) |  |
| Best Budget The cheapest option that still gets the job done reliably | Scotts Turf Builder Southern Lawn Food, 17.65 lb |  |
| Highest Rated A top-rated pick with lots of positive feedback | Ferti-lome Slow Release Nitrogen Lawn Fertilizer 15-0-15 with Iron (2 Pack, 16 lb each) |  |
| Most Popular A crowd favorite that many people choose with confidence | Scotts EZ Patch Lawn Repair for St. Augustine Lawns, 3.75 lb |  |
| Best Seller A high-volume bestseller chosen again and again | Scotts Turf Builder Lawn Food, 37.5 lb. |  |
The Andersons Professional PGF 16-0-8 Granular Lawn Fertilizer with Humic DG, 40 lb
| Form | Granules |
|---|---|
| Specific Uses For Product | Lawns |
| Target Species | lawn grasses |
| Mixing Ratio | 1:4.5 |
The Andersons Professional PGF 16-0-8 is a granular lawn fertilizer designed to deliver both immediate and extended nitrogen feeding while adding humic DG and micronutrients. It is intended for broadcast spreader use on lawns and is applied at 3.6 pounds per 1,000 sq ft every 6 to 8 weeks. The super-fine granules promote even distribution, which helps avoid streaking and ensures more uniform green-up. Because the formula is phosphorus-free and includes iron and Humic DG, it supports turf color and soil health without adding phosphorus. Practical benefits include a mix of quick- and slow-release nitrogen for steady growth, clear directions for application rates, and a resealable bag for storage. Limitations to consider are that it is not labeled for use in some states and centipede lawns require a reduced rate, and like any granular fertilizer, correct spreader calibration and dry application conditions are important to avoid uneven results or runoff risk.
Best for: Buyers who want reliable, performance-focused feeding to green and maintain warm-season lawns like zoysia with predictable scheduling and steady growth.
Less Ideal for: Homeowners seeking a fertilizer to correct phosphorus deficiency or those who need a product approved for restricted states should look elsewhere.
- Blend of quick- and slow-release nitrogen for immediate color and up to eight weeks of feeding
- Super-fine granules for more even spread and reduced streaking
- Includes iron, micronutrients, and Humic DG to support turf color and soil biology
- Clear application rate and schedule guidance with a resealable bag for storage
- Phosphorus-free formula may not address phosphorus-deficient soils
- Not labeled for sale or use in certain states
Verdict: Choose this fertilizer when you want a performance-oriented, even-spreading granular feed that delivers immediate color and up to eight weeks of controlled nitrogen for warm-season lawns like zoysia.
LESCO 50 lb. St. Augustine Grass Weed and Feed (Penoxsulam)
| Item Form | Granules |
|---|---|
| Coverage | St. Augustine Grass (12,000 – 14,000 sq. ft.) |
| Target Species | St. Augustine Grass |
| Mixing Ratio | 1:0:1 |
This LESCO product is a granular weed-and-feed formulated for St. Augustine turf, packaged in a 50 lb bag to cover roughly 12,000 to 14,000 sq ft. It combines a balanced 17-0-17 fertilizer with 30% poly coated sulfur coated urea for slow release feeding up to eight weeks and includes penoxsulam for post-emergent broadleaf weed control in St. Augustine varieties including Floratam. Typical use is to apply when the turf is wet, let granules dry on the grass, and expect visible improvement within about two weeks. The slow-release nitrogen reduces the need for frequent reapplications and the specified coverage makes it practical for medium to large lawns. Limitations are that the formula and coverage are focused on St. Augustine only, so it is not suited for other turf types, and a single 50 lb bag is bulky to handle for small-yard users. Also, as with any weed-and-feed, timing and correct application rate matter to avoid turf stress or uneven results.
Best for: Homeowners with established St. Augustine lawns who want a combined slow-release fertilizer and weed control solution to reduce application frequency and maintain even feeding over weeks.
Less Ideal for: People with mixed-species lawns, small yards where a large bag is impractical, or those who need a pure fertilizer without herbicide active ingredients.
- Formulated specifically for St. Augustine grass, including Floratam.
- Balanced 17-0-17 fertilizer with 30% poly coated sulfur coated urea for up to 8 weeks slow feeding.
- Includes penoxsulam for post-emergent broadleaf weed control.
- Large 50 lb bag covers approximately 12,000–14,000 sq ft, suitable for medium to large lawns.
- Designed only for St. Augustine turf and may damage or be ineffective on other grass types.
- Large bag can be heavy and awkward for a single user to handle and spread manually.
Verdict: A convenient, slow‑release weed-and-feed tailored to St. Augustine lawns that supplies weeks of feeding while controlling broadleaf weeds.
The Andersons Professional PGF Complete 16-4-8 Granular Lawn Fertilizer (covers 5,000 sq ft)
| Item Form | Granules |
|---|---|
| Specific Uses For Product | Soil Conditioning |
| Target Species | lawn grasses |
| Unit Count | 288 Ounce |
| Mixing Ratio | 4-1-2 ratio |
This granular fertilizer is built to boost turf performance with a 16-4-8 N-P-K ratio that delivers both immediate and extended nitrogen release for up to eight weeks. It is typically applied with a broadcast spreader at the recommended rate on dry foliage, then lightly watered to activate the Humic DG technology that helps nutrients move into the root zone. Notable features include super-fine particles for even coverage, added iron and micronutrients for richer color, and a mix of quick and slow-release nitrogen for steady growth without frequent reapplication. Practical benefits for a performance-focused buyer are visibly greener turf, reduced application frequency, and improved soil conditioning from humic acids. Important limitations are that it is a granular product so precise spreader calibration and steady walking are required for uniform results, and it is not labeled for sale in California which restricts availability in that state.
Best for: Gardeners focused on high-performance, visibly greener lawns who want a single application product that delivers both immediate and extended feeding and supports soil health.
Less Ideal for: Small container gardeners or people who prefer liquid or organic-only fertilizer programs should consider other formats or formulations.
- Balanced 16-4-8 N-P-K with both quick- and slow-release nitrogen for immediate color and sustained feeding
- Super-fine particles designed for even distribution across the lawn
- Includes iron and multiple micronutrients to improve turf color and overall plant nutrition
- Humic DG additive to help move nutrients into the soil and support soil conditioning
- Requires correct spreader settings and consistent walking speed to avoid streaking
- Not available for sale in California
Verdict: Choose this fertilizer when you want a performance-focused granular formula that delivers quick color boost plus up to eight weeks of sustained feeding for greener grass.
Scotts Turf Builder Southern Lawn Food, 17.65 lb
| Item Form | Granules |
|---|---|
| Specific Uses For Product | Lawns |
| Target Species | Lawn Grass |
| Mixing Ratio | 34-0-10 |
| Coverage | Full |
Scotts Turf Builder Southern Lawn Food is a granular fertilizer designed for southern lawns and works well when applied with a broadcast spreader and watered in. It supplies an N-P-K ratio described as 34-0-10 and includes added potassium to help St. Augustine and other warm-season grasses handle heat and drought stress. You can apply at the Turf Builder rate for routine feeding across up to 5,000 sq. ft. or use the stronger Max Greening rate for a deeper color when allowed. Practical benefits include visible green-up in as little as three days when directions are followed, simple application with common spreaders, and clear guidance on timing and safety around kids and pets after watering. Limitations are that it contains no phosphorus, so it will not support root development needs that require phosphorus, and it is best used during active growing temperatures between 60°F and 90°F so it is not suitable for dormant-season feeding. For budget-conscious homeowners, one bag covers a large area which helps stretch cost across several applications per year.
Best for: Homeowners with St. Augustine or other southern warm-season lawns who want an easy-to-apply, economical fertilizer that improves color and drought resilience during the growing season.
Less Ideal for: Gardeners needing a phosphorus-containing formula for root establishment or those who need a fertilizer to apply during cool or dormant periods.
- Formulated for southern warm-season grasses with added potassium to improve heat and drought tolerance
- Visible greening reported in as little as three days when used as directed
- Covers up to 5,000 sq. ft. at the Turf Builder rate, making it economical per application
- Safe for kids and pets to re-enter the lawn once product is watered in according to label
- No phosphorus in the listed N-P-K, so it will not address phosphorus deficiencies
- Effective only when temperatures are consistently between 60°F and 90°F, limiting timing for application
Verdict: A practical, budget-friendly granular fertilizer for southern lawns that delivers fast greening and improved heat tolerance when applied during the growing season.
Ferti-lome Slow Release Nitrogen Lawn Fertilizer 15-0-15 with Iron (2 Pack, 16 lb each)
| N‑P‑K | 15-0-15 |
|---|---|
| Item Form | Granules |
| Target Uses | Lawn Care |
| Included Components | Lawn Fertilizer |
This two‑bag pack of Ferti-lome 15-0-15 delivers slow‑release nitrogen with added iron to maintain color and steady growth on warm and cool season lawns. Each 16 lb bag is intended to cover up to 4,000 sq ft, so the bundle is convenient for larger yards or for having a spare for the next application. Typical use is a spring and fall feeding at the recommended rate, applied with a broadcast or drop spreader; the slow‑release formulation reduces the need for frequent reapplication and helps avoid quick flushes of growth. The inclusion of iron and micronutrients improves leaf color without extra liquid treatments, and compatibility with many grasses makes this usable on Empire Zoysia. Limitations are that the blend has no phosphorus and is focused on nitrogen and potassium balance, so soils needing phosphorus will require a separate product, and precise coverage depends on correct spreader settings and uniform application. For homeowners prioritizing predictable, low‑maintenance feeding and improved lawn color, this pack is a practical choice.
Best for: Homeowners who want a dependable, low‑maintenance fertilizer regimen and need steady feeding and color improvement across a sizable Empire Zoysia lawn.
Less Ideal for: Gardeners whose soil tests show a phosphorus deficiency or who need a specialized nutrient program focused on establishing new turf should consider a different formula.
- Slow‑release nitrogen provides extended feeding and fewer applications
- Contains iron and micronutrients to enhance leaf color
- Two 16 lb bags cover large areas or allow for a follow-up application
- Suitable for a wide range of grass types including warm‑season Zoysia
- No phosphorus in the 15-0-15 formula so it will not correct phosphorus deficiencies
- Effective, even coverage requires correct spreader calibration and application technique
Verdict: Choose this two‑pack slow‑release 15-0-15 fertilizer when you want predictable, low‑frequency feeding and improved color for an established Empire Zoysia lawn.
Scotts EZ Patch Lawn Repair for St. Augustine Lawns, 3.75 lb
| Item Form | Mulch and Fertilizer Mix, Ready-to-use |
|---|---|
| Coverage | 85 sq ft |
| Target Species | St. Augustinegrass |
| Unit Count | 60 Ounce |
Scotts EZ Patch is a ready-to-use mulch and fertilizer blend specifically formulated for St. Augustinegrass to help repair bare spots and establish plugs. You prep the spot by removing dead material and loosening soil, spread an even layer of the mix so no soil shows, then water until the mulch is saturated. The product’s super-absorbent mulch expands and holds moisture to protect newly exposed soil while the controlled-release fertilizer feeds the grass over time, which the brand says can speed visible repair. Because it contains no seed, it is best used with plugs or to cover recently installed sod rather than for overseeding. The small 3.75 lb jug covers up to 85 sq ft, making it convenient for spot repairs but not for large lawns. For homeowners looking for a simple three-step patch method, this is easy to apply and reduces the need for daily watering; users should plan to combine it with proper plug or sod selection and routine turf care for best results.
Best for: Homeowners with St. Augustine lawns who want an easy, low-effort product to repair bare spots or protect newly placed plugs and sod and who value proven product performance.
Less Ideal for: People trying to reseed large areas or establish a whole lawn from seed should choose a seed-containing product or larger coverage solution.
- Formulated specifically for St. Augustinegrass to support faster establishment
- Super-absorbent mulch expands to retain moisture and improve coverage
- Controlled-release fertilizer feeds turf over time to encourage growth
- Ready-to-use mix requires no measuring or mixing and is simple to apply
- Does not contain grass seed so it cannot establish turf on its own
- Small container size is suitable for spot repairs but not large areas
Verdict: A simple, ready-to-use mulch plus controlled-release fertilizer made to protect and speed repair of St. Augustine bare spots when used with plugs or sod.
Scotts Turf Builder Lawn Food, 37.5 lb.
| Item Form | Granules |
|---|---|
| Specific Uses For Product | Lawn |
| Coverage | 15000 |
| Mixing Ratio | 32:0:4 |
Scotts Turf Builder Lawn Food is a granular, all-purpose lawn fertilizer formulated to thicken and green lawns while building deeper roots. It is used by broadcasting with a spreader or dropping with a drop spreader; Scotts gives specific spreader settings for easy, repeatable application. The bag covers a large area so it is convenient for whole-yard spring feeding routines. Practical benefits include improved root strength and better nutrient and water uptake compared with unfed turf, plus flexible timing since it can be applied to wet or dry grass and lightly watered in for faster greening. The product is pesticide-free and intended for any grass type, so it can fit into a seasonal program for warm-season grasses like Zoysia. Limitations are that it is a straight lawn food without weed control or insect ingredients, so you will need separate products for weeds or pests, and handling a 37.5 lb bag can be bulky for small yards or single-application needs.
Best for: Homeowners who want a straightforward, high-coverage spring fertilizer to strengthen and green their Zoysia lawn as part of a planned feeding routine.
Less Ideal for: Gardners who need one-step weed and feed or combined pest control solutions or those with very small lawns who prefer smaller package sizes.
- Covers up to 15,000 sq. ft. from one 37.5 lb. bag
- Formulated to build stronger roots and improve nutrient uptake
- Can be applied to wet or dry lawns and used with common spreaders
- Pesticide-free lawn food suitable for any grass type
- Does not include weed or insect control so additional products may be required
- Large bag size may be awkward for small properties or single applications
Verdict: A simple, high-coverage lawn food that reliably builds root strength and greens Zoysia when used as part of a seasonal feeding plan.
Choosing the Right Yard Fertilizer for St. Augustine Grass: Key Factors to Consider
Nutrient Ratio and Timing
St. Augustine is a warm-season turf that responds strongly to nitrogen but can suffer from excessive top growth and disease if fed improperly. Look for fertilizers with nitrogen levels suited to your yard's vigor and soil test recommendations.
Timing matters as much as ratio. Early spring and late spring applications support active growth, while midsummer feeds can stress turf in heat unless slow-release nitrogen is used. Fall applications should be conservative to avoid pushing tender growth before dormancy.
Release Rate and Nitrogen Source
Slow-release nitrogen provides steady color and reduces the risk of burn and excessive thatch, while soluble nitrogen gives faster green-up. Choosing a blend lets you balance immediate visual improvement with long-term turf health.
Consider the proportion of coated or polymer nitrogen versus urea or ammonium forms. Higher slow-release content is usually safer during hot, dry periods and in lawns with poor irrigation control.
Application Method and Equipment Compatibility
Granular and liquid fertilizers behave differently in a yard. Granules are easy to apply with a broadcast spreader and are forgiving for spot treatments. Liquids can offer quicker uptake and more uniform coverage with a sprayer but require calibration and more frequent applications.
Check label instructions for recommended spreader settings or spray rates. Compatibility with the equipment you already own will save time and reduce the chance of uneven feeding that can create striping or burn spots.
Salt Index and Turf Safety
Some fertilizers have a higher salt index, which increases burn risk on drought-stressed or newly sodded St. Augustine. Products with lower soluble salt content or higher slow-release fractions are gentler on roots.
Also consider seedling and sod safety if you are establishing new turf. Verify label recommendations for newly installed sod or for overseeding, since young stolons and roots are more vulnerable to concentrated feeds.
Thatch and Disease Influence
Overfertilizing can accelerate thatch accumulation in St. Augustine, creating a moist layer that fosters disease. Fertilizers that encourage balanced root development and include slow-release components help limit thatch buildup.
Timing and nitrogen amount also influence disease risk. Heavy nitrogen in warm, humid conditions can invite fungal issues. Integrating cultural practices like proper mowing height and core aeration with your fertilizing plan reduces those risks.
Trace Nutrients and Soil Compatibility
Beyond N-P-K, St. Augustine benefits from adequate iron and micronutrients, especially in high pH or sandy soils where deficiencies show as chlorosis. Some yard fertilizers include chelated iron or micronutrient blends tailored to turf needs.
Soil testing informs whether you need supplemental phosphorus or potassium and helps avoid unnecessary applications. Matching a fertilizer to your soil's baseline prevents nutrient imbalances that harm turf structure and performance.
When to Feed St. Augustine Grass
Feed in active growth windows: typically late spring through early summer for most warm-season lawns. Initiate feeding after stolons are actively growing and temperatures are consistently warm.
Avoid heavy fertilization during heat spikes and drought. If you must feed in summer, use a product with significant slow-release nitrogen and make sure irrigation is available to reduce burn risk.
- Start spring applications when soil temperatures are consistently above 65°F.
- Space regular maintenance feeds every 6 to 8 weeks depending on release profile.
- Limit late fall nitrogen to avoid tender growth before dormancy.
How Soil Tests Guide Fertilizer Choice
A simple soil test tells you baseline nutrient levels and pH, which directs the choice of N-P-K ratios and the need for micronutrients. For instance, low iron or high pH conditions may benefit from iron-containing formulations or pH adjustments.
Use the test to tailor application rates rather than guessing. Applying fertilizer based on science reduces waste, prevents excess thatch, and protects nearby plants and waterways.
- Test every 2 to 3 years or after major soil amendments.
- Share results with a local extension service if you need interpretation.
Adjusting Fertilizer for Soil Type and Irrigation
Sandy soils leach nutrients faster and may benefit from smaller, more frequent applications or higher slow-release content to maintain steady availability. Clay soils hold nutrients longer but can retain moisture, so watch for overfeeding and disease.
Irrigation frequency affects how fertilizer behaves. Regular watering after granular application helps move nutrients into the root zone. For liquid feeds, plan applications when you can water lightly if recommended.
- Use slow-release formulations on sites with infrequent irrigation.
- Split applications on sandy sites to reduce nutrient loss.
Mowing, Aeration, and Fertilizer Timing
Coordinating mowing and aeration with fertilization improves uptake and reduces thatch. Core aeration before a major feed helps nutrients penetrate the root zone and encourages deeper rooting.
Keep mowing height at the recommended range for St. Augustine to reduce stress and to allow fertilizer to support root development rather than just top growth.
- Aerate in late spring or early summer before heavier feeding.
- Avoid mowing immediately after liquid applications when leaf wetness could spread product unevenly.
Spot Treatments and Repair Feeding
For small bare patches or thin areas, use a targeted, low-salt fertilizer and follow with overseeding or sodding practices appropriate for St. Augustine. Spot feeding can revive struggling stolons if moisture and cultural conditions are corrected.
Avoid heavy spot applications that create uneven growth or localized burn. Apply at reduced rates and water in lightly to distribute nutrients.
- Use a starter-style approach for new sod or plugs with a milder nutrient concentration.
- Combine spot feeding with soil contact improvement like topdressing or aeration.
How We Chose the Best Yard Fertilizer for St. Augustine Grass
We selected fertilizers that match the specific nutrient and cultural needs of St. Augustine grass and that perform reliably across common yard conditions. Our filters prioritized appropriate nitrogen-to-phosphorus-to-potassium ratios for warm-season turf, a mix of fast- and slow-release nitrogen sources, and clear instructions for application timing tied to regional growth cycles. We also considered fertilizer granule or liquid consistency relative to spreader or sprayer compatibility, salt index and suitability for salt-prone sites, and whether the product minimizes thatch and reduces disease pressure. Safety and label clarity were required; products without clear lawn rates, reentry intervals, or turf-specific guidance were excluded. Finally, we favored options that reduce burn risk when used per label and that allow predictable green-up without excessive top growth.
FAQ
How often should I fertilize St. Augustine grass?
Usually feed St. Augustine every 6 to 8 weeks during the active growing season, adjusting frequency based on the product's release profile. Slow-release formulations allow longer intervals while soluble feeds need more frequent application.
Can I fertilize during summer heat?
You can, but choose slow-release nitrogen and ensure the lawn is not drought-stressed. Avoid heavy soluble nitrogen during heat waves, and water appropriately after application to reduce burn risk.
Do I need phosphorus for established St. Augustine lawns?
Most established lawns do not need extra phosphorus unless a soil test shows deficiency. Overapplication can harm turf and the environment, so follow soil test recommendations for phosphorus rates.
Will fertilizer reduce my thatch problem?
Properly balanced, moderate fertilization can reduce conditions that promote excessive thatch by encouraging deeper rooting. However, overfertilization can increase thatch, so combine feeding with aeration and dethatching when necessary.
Should I use a different fertilizer on new sod or plugs?
New sod and plugs need gentler starter feeds with lower salt and sometimes higher phosphorus to support root establishment. Follow guidelines for starter rates and avoid full-strength maintenance fertilization until roots are established.
Final Verdict
Prioritize a fertilizer that matches your soil test results and the growth rhythm of St. Augustine grass. Aim for a nutrient balance that provides steady nitrogen with a good slow-release component, low salt index for safety, and label instructions that fit your equipment and schedule. Balance faster green-up with long-term turf health by coordinating feeding with aeration, proper mowing, and irrigation. Focus on the criteria discussed here to choose a plan that builds dense, disease-resistant St. Augustine turf rather than just quick color.
