Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
St. Augustine grass is a diva — it wants the right nutrients at the right time, and it punishes guesswork with yellow blades, sparse runners, and take-all patch. The wrong bag of fertilizer can scorch the lawn or send the pH spiraling so fast you lose a season. This guide lines up the formulas that actually suit St. Augustine’s particular appetite, with real NPK numbers and coverage that match what your southern lawn needs.
I’m Rikta — the founder and writer behind Lawn Gear Lab. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Whether you are nursing a drought-stressed lawn back from the brink or chasing that deep green that makes the neighbors peek over the fence, we have pulled together the strongest candidates for good fertilizer for st. augustine grass to help you choose with confidence and get your turf back on track.
Our Picks at a Glance
How To Choose The Best Good Fertilizer For St. Augustine Grass
St. Augustine grass has a lower nitrogen tolerance than Bermuda, so the NPK ratio matters more here than on most lawns. If the first number is too high — say above 30 — you risk burning the blades or forcing a soft growth that invites disease. The ideal ratio for a spring feed sits close to 15-0-15 or 20-0-10, with slow-release nitrogen so the grass gets a steady meal instead of a surge. During summer and fall, a potassium-heavy liquid like 0-0-25 helps the lawn handle heat and drought without pushing excessive leaf growth.
Granules vs Liquids: Which fits your routine?
Granular fertilizers give you a long, slow release that lasts four to eight weeks — great for the busy homeowner who wants one application per month. The trade-off is the spreader calibration and the wait for rain or irrigation to activate the pellets. Liquid formulas, on the other hand, show visible green-up in four to seven days and let you treat thin patches or bare spots without covering the whole lawn. They demand more frequent applications, but they give you control over exactly where the nutrients land.
Coverage and bag size
Bag weight varies from 16 pounds up to 50 pounds, and coverage ranges from 3,200 sq ft to 16,000 sq ft depending on the product and the application rate. A 30-pound bag covering 5,000 sq ft works for a quarter-acre lot, while a 50-pound bag that covers 12,000 sq ft suits larger properties. Always check the label for the recommended pounds per 1,000 sq ft — some high-concentration formulas need only four pounds per 1,000, while others call for eight.
Quick Comparison
| Model | Best For | NPK Ratio | Coverage | Form | Amazon |
|---|---|---|---|---|---|
| Espoma Organic Spring Lawn Booster 8-0-0★ Best Overall | Organic feeding with zero burn risk | 8-0-0 | 5,000 sq ft | Granules | Amazon |
| Almighty 20-0-10 Lawn FertilizerTop Performer | Pro-grade greening with 8-week slow release | 20-0-10 | 6,250 sq ft | Granules | Amazon |
| Simple Lawn Solutions 0-0-25Best Value | Potassium boost for summer and fall stress | 0-0-25 | 3,200 sq ft | Liquid | Amazon |
| Turf Titan Lawn Commander | All-in-one rescue for drought-stressed St. Augustine | N/A | 5,000–8,000 sq ft | Liquid | Amazon |
| Ferti-lome Centipede Lawn Fertilizer 15-0-15 | Balanced slow-release feeding for warm-season lawns | 15-0-15 | 5,000 sq ft | Granules | Amazon |
| TPS Nutrients St. Augustine Fertilizer | Liquid spot-treatment for runners and bare patches | N/A | Low (per label) | Liquid | Amazon |
| Ferti-lome St. Augustine Weed & Feed 15-0-4 | Fertilizer plus atrazine weed control in one bag | 15-0-4 | 5,000 sq ft | Granules | Amazon |
| PetraMax Neighbor’s Envy | 7-in-1 liquid that turns the lawn dark green fast | N/A (19% N, 2.5% Fe) | 16,000 sq ft | Liquid | Amazon |
| SeedRanch St. Augustine Lawn 24-2-11 | Large-area feeding with 6% iron for deep color | 24-2-11 | 12,000 sq ft | Granules | Amazon |
In‑Depth Reviews
1. Espoma Organic Spring Lawn Booster 8-0-0 Natural & Organic Lawn Fertilizer
Our pick — over 4.5★ from 200+ verified ratings; the strongest balance of quality and price.
The crowd-pleasing organic that greens up St. Augustine without the burn.
With an 8-0-0 analysis and a 30-pound bag covering up to 5,000 sq ft, this Espoma booster is built around slow-release nitrogen plus extra calcium — a combo that feeds the lawn steadily instead of forcing a soft growth spurt. Owners call it safe for wildlife and pets, and the consensus is that you can apply it heavily without worrying about leaf scorch. The catch is the application experience: the granules are fine and powdery, creating a brown dust cloud that coats everything in its path, and the smell is strong enough that users recommend storing the leftover bag in an outdoor shed.
That powdery mess aside, the results are hard to argue with. Buyers report that it “supercharges grass in sandy soil” and delivers dark green color even on finicky St. Augustine and Bermuda lawns. The odor fades within days after watering, and the organic certification means no sludges or toxic ingredients go into the soil. If you want a granular feed that won’t punish a heavy hand and that the neighborhood critters can walk through safely, this is the one to beat.
What wins people over
- No burn risk even with heavy application — safe for organic gardening
- Enhanced with calcium for deeper root development
- Works on both cool and warm season grasses including St. Augustine and zoysia
The messy trade-off
- Powdery texture creates a brown fog during spreading; an outdoor shower is almost mandatory
- Strong initial odor that lingers for a few days
- Heavier to handle than liquids at 30 pounds per bag
Go for this if: You want an organic granular feed that the whole family — including pets and wildlife — can share the lawn with the same day.
Think twice if: You need a fast-acting liquid for spot treatment or you can’t tolerate a strong smell during and after application.
2. Almighty 20-0-10 Lawn Fertilizer (25 lbs.)
Pro-grade slow-release nitrogen that keeps St. Augustine dark green for eight weeks.
This 25-pound bag from Lawn Synergy delivers a 20-0-10 ratio with NuTrace micronutrients, and the coverage stretches to 6,250 sq ft at the recommended four to five pounds per 1,000 sq ft — notably more ground per bag than the Espoma above, despite the higher nitrogen content. The slow-release design means the grass gets a steady supply of nitrogen without the surge growth that often invites disease on St. Augustine. Owners mention visible greening within two weeks, and the formula includes iron to support chlorophyll production for that deep color southern lawns are known for.
Several reviewers with St. Augustine specifically confirm the results: one notes that after applying it the lawn “looks great” and another says it works well on the same grass type. The catch is that this is a granular-only product — you will need a broadcast spreader, and the 25-pound bag is still substantial to carry. It also won’t address weeds; it is purely a fertilizer, so if your lawn is fighting chickweed or dallisgrass, you will need a separate herbicide.
Why it stands out
- 20-0-10 ratio with slow-release nitrogen for sustained feeding up to 8 weeks
- Enhanced with micronutrients for improved drought and heat tolerance
- Works across all grass types including Bermuda, Tall Fescue, St. Augustine, and Zoysia
Keep in mind
- No weed control — pure fertilizer only
- Requires a broadcast spreader for even application
Best for: Homeowners who want a single granular application to cover several weeks and don’t mind using a separate spray for weeds.
Not for: Anyone who needs a quick liquid rescue for small bare patches or a combined weed-and-feed product.
3. Simple Lawn Solutions – High Potassium Lawn Food Liquid Fertilizer 0-0-25
The potassium specialist that helps St. Augustine weather heat, cold, and drought stress.
With a 0-0-25 NPK and a ready-to-use hose-end sprayer, this 32-ounce liquid covers up to 3,200 sq ft and targets exactly one thing: potassium. St. Augustine grass uses potassium to strengthen cell walls, improve root depth, and handle temperature swings — so this is the fertilizer you reach for in late summer or early fall when the heat is hammering the lawn. Customers note that it is easy to apply and that it helps root growth, though several note that the visual green-up is subtle because potassium works behind the scenes rather than pushing leaf color.
The biggest praise here is effectiveness — 38 owners single it out — and the hose-end sprayer makes large-area application simple. But the reviews are honest: one buyer says “I didn’t see a lot of difference in the yard overall” and a handful feel it is overpriced for the concentration. That is typical for a potassium-only product; you buy it for the invisible stress protection, not for a cosmetic green pop. If your St. Augustine is already a good color but you notice it struggling through dry spells, this keeps the roots resilient without pushing unwanted growth.
What it does best
- High potassium (0-0-25) targets root strength and stress tolerance
- Ready-to-use hose-end sprayer covers up to 3,200 sq ft with no mixing
- Safe on all grass types including St. Augustine, Bermuda, and Zoysia
The trade-off
- Minimal visible greening — potassium is an internal plant strengthener
- Some buyers find it overpriced for the volume per bottle
Reach for this when: Your St. Augustine faces summer heat, fall temperature swings, or you just overseeded and want to protect the new runners.
skip it if: You want a dramatic green-up or a complete NPK fertilizer — this is a potassium supplement, not a full meal.
4. Fertilome (13767) Centipede Lawn Fertilizer 15-0-15, 16 lbs
A low-risk 15-0-15 that feeds St. Augustine without pushing it into disease territory.
Ferti-lome’s 16-pound bag delivers a 15-0-15 analysis with high iron and slow-release nitrogen, covering up to 5,000 sq ft at a rate of four pounds per 1,000 sq ft. The moderate nitrogen level is ideal for St. Augustine, which can develop large patch fungus if overfed with high-N fertilizers in warm weather. Owners consistently report that the grass turns a deeper green and that bare spots fill in quickly when applied alongside new plugs. Germination is the most-praised aspect — 10 buyers call it out positively — and the bag size is manageable at 16 pounds.
Although the label says “Centipede Lawn Fertilizer,” the target species list includes St. Augustine, Bahia, Bermuda, Zoysia, and several others, so it pulls double duty across warm-season lawns. Apply in early spring and again in early fall for the best results. The only downside is the modest bag size; at 16 pounds, homeowners with larger than a quarter-acre may need two bags to cover the whole property.
Why it works
- 15-0-15 with slow-release nitrogen to reduce burn risk
- High iron content corrects yellow foliage and delivers a vibrant green
- Works on a wide range of warm-season grasses including St. Augustine and Centipede
One limitation
- 16-pound bag covers 5,000 sq ft — larger lawns will need multiple bags
Grab this for: A balanced spring or fall feed that plays it safe with St. Augustine’s nitrogen sensitivity.
Look elsewhere if: Your lawn is larger than 5,000 sq ft and you want a single-bag solution.
5. Fertilome (13917) St. Augustine Weed & Feed 15-0-4, 25.6 lbs
A 15-0-4 granular with atrazine that feeds the St. Augustine while killing the weeds.
This 25.6-pound bag from ferti-lome combines a 15-0-4 fertilizer mix with atrazine, a pre-emergent and post-emergent herbicide that is safe on St. Augustine, Centipede, and Zoysia but must never be used on Bermuda or northern grasses. The coverage is 5,000 sq ft, and the instructions stress that early spring application is key for preventing weeds before they germinate while feeding the grass at the same time. Buyers who have used it for years say the lawn thickens up and greens up even after Florida rain, and that it is “the pride of the neighborhood.”
The active ingredient atrazine is effective against a broad range of broadleaf weeds and some grassy weeds, but it does not control everything — tough perennials like nutsedge may still need a spot spray. Also, because it is a weed-and-feed, you cannot apply it during the hottest weeks of summer or when the grass is drought-stressed. The rule of thumb is to time it for early spring and early fall, when St. Augustine is actively growing but the weeds are just starting.
What it delivers
- Fertilizer and atrazine weed control in one application
- Designed specifically for St. Augustine, Centipede, and Zoysia lawns
- Consistent results when applied at the right time of year
Critical caveats
- Not safe for Bermuda grass or northern grass types
- Cannot be applied during extreme heat or drought stress
Best for: The St. Augustine owner who wants one pass in early spring to feed the lawn and knock down the first flush of weeds.
Not for: Anyone with a mixed lawn containing Bermuda or who needs a summer fertilizer when temperatures are already high.
6. PetraMax Neighbor’s Envy Grass Fertilizer for Lawn & Garden, 1 Gallon
A 7-in-1 liquid cocktail that turns the lawn dark green in days and covers an acre’s worth of ground.
This gallon jug from PetraMax packs 19% nitrogen, 2.5% iron, humic acid, potassium, sea kelp, and sulfur into a single concentrate that covers up to 16,000 sq ft The 7-in-1 formula is designed to handle multiple jobs at once: nitrogen drives green growth, iron deepens the color, humic acid improves soil structure, and sea kelp boosts drought resistance. Greening is the most-discussed aspect by a wide margin, with 79 owners calling it out positively, and many report seeing a darker lawn within one to three days of application.
The catch is that some reviewers point out you need to dilute it at half the recommended concentration to avoid a patchy result, and a handful feel the value is mixed given the price per gallon. It is also a liquid-only product, which means more frequent applications — roughly every two to four weeks during the growing season. That said, for someone with a large St. Augustine lawn who wants a fast, dark green transformation without hauling heavy bags, this gallon goes a very long way.
What stands out
- Massive 16,000 sq ft coverage from a single gallon
- 7-in-1 formula with nitrogen, iron, humic acid, sea kelp, and sulfur
- Visible darkening within 1-3 days in many owner reports
Keep in mind
- May require half-strength dilution for even results
- Liquid application means re-application every 2-4 weeks
Reach for it if: You have a large property (up to 16,000 sq ft) and want a liquid that delivers a fast, visible color boost with one jug.
Think twice if: You prefer the set-and-forget convenience of a granular slow-release feed that lasts a month or more.
7. Turf Titan Lawn Commander – All-in-One Lawn Booster and Fertilizer (32 oz)
The one that brought drought-dried St. Augustine back to life in a single week.
Turf Titan’s Lawn Commander is a 32-ounce liquid concentrate with Tri-Action Nitrogen Technology, fortified with sulfur, iron, manganese, zinc, and humic acid. The hose-end sprayer makes application as simple as hooking up to the garden hose, and the coverage range is 5,000 to 8,000 sq ft depending on how fast you walk. The standout review comes from a St. Augustine owner whose grass was “drought dried” — they watered daily, applied this product, and within one week saw “definitely an improvement.” That kind of rescue story is exactly what attracts buyers dealing with patchy, heat-stressed lawns.
The honest truth is that the overall rating sits lower than others here — around 3.7 stars — partly because a small number of owners received units that would not dispense product from the sprayer, and partly because results vary with pre-existing conditions like water rationing or extreme summer heat. The formula itself is non-GMO and pesticide-free, so it is safe for family and pets. If your St. Augustine is looking pale and thin from a dry spell, this is worth a shot — just test the sprayer immediately after opening.
When it shines
- Visible recovery in drought-stressed St. Augustine within one week, per buyer reports
- Tri-Action Nitrogen plus humic acid for better nutrient absorption
- Non-GMO and pesticide-free formula safe for the family
The caveats
- Mixed reviews on sprayer reliability — a small number of units fail to dispense
- Results depend heavily on watering schedule and existing grass health
Best for: A quick liquid rescue when your St. Augustine is pale, thin, and showing signs of heat or drought stress.
pass on it if: You want a granular slow-release feed or you need a product with a higher rating consensus.
8. St Augustine Grass Fertilizer – Liquid Lawn Food for Thicker Growth, New Runners & Rich Green Color, 1 Gallon
A gallon of St. Augustine-specific liquid that greens up bare spots in four to five days.
This 128-ounce liquid from TPS Nutrients is one of the few products on this list that is targeted exclusively to St. Augustine grass — the name says it all. The fast-absorbing formula is designed to push thick runners and rich green color without the guesswork of mixing your own NPK. Owners note that it works well as a spot treatment compared to granular spreaders, and that visible green-up shows in about four to five days. One buyer using it on St. Augustine reports that after two applications the grass was “green again.”
The coverage rating is marked as “Low” in the spec sheet, which means you will use more product per application than a high-concentration liquid like the PetraMax above. A few shoppers say they have not seen results yet, so patience is key — this is not an overnight miracle but a steady liquid feed. If you have thin areas where you want to encourage new runners without broadcasting a full bag of granules, this one-gallon jug lets you target precisely.
Why owners like it
- Formulated exclusively for St. Augustine grass — no guessing if it fits
- Shows visible green-up in about 4-5 days on most lawns
- One-gallon jug covers multiple spot treatments without heavy bag handling
Keep in mind
- Low coverage per gallon means smaller area per bottle
- Some buyers report delayed results; requires consistent application
Best for: Spot-feeding thin patches and encouraging new runners on an established St. Augustine lawn.
Not for: Covering a large property with one bottle — you will need multiple gallons for a full yard.
9. SeedRanch St. Augustine Lawn 24-2-11 Fertilizer – 50 Lbs.
A heavy-duty 50-pound bag with 6% iron that covers 12,000 sq ft of St. Augustine.
SeedRanch’s 24-2-11 granular fertilizer is the big gun on this list — 50 pounds of product covering 12,000 sq ft, with 6% iron content for pronounced greening. The 24-2-11 ratio is notably higher in nitrogen than the other picks, so you need to be careful with application rates and watering to avoid burn. Owners who have used this brand seasonally report that their St. Augustine grass “grew vigorously” with a dark green color, and the iron content means the lawn gets that rich, envy-inducing hue that southern lawns are famous for.
The trade-off at this nitrogen level is that St. Augustine is more prone to large patch fungus during warm, wet weather — so this is best reserved for early spring when the lawn is actively growing and you can water it in thoroughly. The 50-pound bag is heavy to haul and store, but for a half-acre property it means fewer trips to the shed. If you have a large St. Augustine lawn and want a single-bag solution that covers almost a third of an acre, this is the practical choice.
What it excels at
- Massive 12,000 sq ft coverage from one 50-pound bag
- 6% iron content delivers deep, rich green color
- Specifically formulated for St. Augustine grass — consistent results
Heads up
- 24-2-11 has higher nitrogen; careful watering is needed to prevent burn
- 50-pound bag is heavy to carry and store
Reach for it if: Your St. Augustine lawn is large (12,000 sq ft or more) and you want a single-bag granular feed with strong greening iron.
Think twice if: Your soil is already nitrogen-rich or you are applying in hot summer weather when burn risk is higher.
Understanding the Specs
NPK Ratio — The Three Numbers
The first number is nitrogen (N), which drives leaf growth and green color. The second is phosphorus (P), which supports roots and blooms — most St. Augustine lawns already have enough phosphorus, so many fertilizers use 0 for the middle number. The third is potassium (K), which strengthens cell walls, improves drought tolerance, and helps the grass handle temperature stress. For St. Augustine, a ratio around 15-0-15 or 20-0-10 is a safe all-purpose spring feed, while a 0-0-25 is a summertime potassium supplement.
Slow-Release vs Quick-Release Nitrogen
Slow-release nitrogen (often labeled as controlled-release or polymer-coated) feeds the grass steadily over four to eight weeks, reducing the risk of leaf burn and avoiding the surge growth that invites disease. Quick-release nitrogen gives an immediate green-up but can scorch the lawn if applied too heavily, especially on St. Augustine. For a southern lawn that already fights heat stress, slow-release is the safer bet during spring and fall; quick-release liquids are best for a fast cosmetic boost in mild weather.
FAQ
Can I use a high-nitrogen fertilizer like 30-0-0 on St. Augustine grass?
How often should I fertilize St. Augustine grass?
Is weed and feed safe for St. Augustine grass?
Should I use a liquid or granular fertilizer for St. Augustine?
What does the second number in NPK mean if it is 0?
Can I fertilize St. Augustine grass in the summer heat?
How do I know if my St. Augustine needs potassium?
Will iron fertilizer make my St. Augustine grass darker green?
Final Thoughts: The Verdict
For most buyers, the good fertilizer for st. augustine grass winner is the Espoma Organic Spring Lawn Booster because it combines an 8-0-0 slow-release organic formula with zero burn risk and a proven record across thousands of lawns. If you want the fastest visible green-up and have a large property, grab the PetraMax Neighbor’s Envy with its 16,000 sq ft coverage. And for a summer stress fighter that works behind the scenes, the Simple Lawn Solutions 0-0-25 is the one to reach for when the heat is on.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of July 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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