Best Fertilizer for St. Augustine Grass in Texas (2026 Top Picks)

NPK Targets for Texas St. Augustine

St. Augustine is a heavy nitrogen feeder. The total annual target across a full season is 3 to 5 lbs of actual nitrogen per 1,000 square feet. Lean toward the lower end (around 3 lbs) on sandy East Texas soils where you want to avoid pushing soft growth, and toward the higher end (4 to 5 lbs) on a vigorous, well-watered Gulf Coast lawn on heavier soil. Note that this is "actual nitrogen," not bag weight. A 16-4-8 bag is 16 percent nitrogen, so a 20 lb bag delivers about 3.2 lbs of actual N.

The ratio matters as much as the total. A balanced slow-release blend in the neighborhood of 16-4-8 is the sweet spot for St. Augustine: enough nitrogen to drive color and density, a modest amount of phosphorus, and meaningful potassium for heat, drought, and disease tolerance. That potassium (the third number) is doing quiet, important work in Texas because it strengthens cell walls and improves stress resistance heading into the brutal stretch from June through August. Avoid high-phosphorus "starter" blends on established lawns; most Texas soils already hold plenty of phosphorus, and overdoing it does nothing good.

Here is the part that trips up Central Texas homeowners. If your alkaline Blackland or caliche soil is locking up iron, adding more nitrogen will not green the lawn back up. It will just push growth that stays yellow (a condition called iron chlorosis). The answer is supplemental iron, which I will detail in the products and problems sections below. Bottom line on targets:

• Annual nitrogen: 3 to 5 lbs N per 1,000 sq ft, split into 4 to 6 feedings.
• Ratio: balanced slow-release around 16-4-8 (high N, low to moderate P, real K).
• Per application: roughly 0.5 to 1 lb of actual N per 1,000 sq ft, never more than 1 lb at once.
• Iron, not nitrogen, for yellowing on high-pH Central Texas soil.

Top Fertilizers for Texas St. Augustine (2026)

These are the products I recommend most for Texas St. Augustine in 2026, sorted by use case. The comparison table puts them side by side, and the notes below walk through when each one earns its spot in your shed. Every link goes to the current product so you can check the latest details before buying.

The Andersons PGF Complete 16-4-8 (editor pick)

This is the one I put in most Texas St. Augustine yards. The 16-4-8 ratio is exactly what this grass wants, the prill is fine and dispersive (it works into the canopy and breaks down without leaving visible granules), and the 7% humic DG actually helps soil biology, which matters on tired Texas clay. It is slow-release enough to feed steadily through heat without a growth spike. Use it as your backbone product spring through early fall.

Milorganite 6-4-0

Milorganite is the gentle, organic, slow-release option that also delivers iron, so it greens up the lawn without forcing growth. That makes it ideal for a midsummer feeding when you want color but do not want to push soft tissue into chinch bug and gray leaf spot season. The low nitrogen number means you apply more product per pass, but it is nearly impossible to burn the lawn with it, even in July.

Dark Matter 21-0-0 Ammonium Sulfate

When a lawn looks tired and you want a fast, even green-up, ammonium sulfate with iron does it. The sulfate also has a mild acidifying effect, which is a small bonus on alkaline Central Texas soil. This is more fast-release, so keep applications light (no more than 1 lb of N per 1,000 sq ft) and water it in well, especially in heat.

Scotts Southern Turf Builder

The big-box, grab-it-on-the-way-home option. It is formulated for southern grasses including St. Augustine, it spreads easily, and it is widely available. It is not as agronomically tuned as the PGF, but it is a perfectly solid choice for a homeowner who wants one bag and simple instructions.

Advanced 16-4-8 Liquid

A liquid 16-4-8 is your spot-feeding and quick-uptake tool. It is great for new sod or plugs that have not rooted enough to handle granular, for evening out a thin area, or for a fast foliar pick-me-up. Liquids feed quickly but do not last as long as granular slow-release, so think of this as a supplement, not your main program.

Ironite II 1-0-0 and Southern Ag Chelated Liquid Iron

These two are the Central Texas color insurance. Ironite II is a granular iron supplement (1-0-0) that greens a high-pH lawn without dumping on nitrogen, and the Southern Ag chelated liquid iron is the fast-acting version you spray when a yard goes yellow and you need it green for the weekend. Chelated iron stays available in alkaline soil longer than plain iron sulfate, which is why it is the smart pick for Blackland clay.

Espoma Organic All Season and Pennington 32-0-5

Espoma is the choice for folks who want a fully organic, soil-building program and a product that is gentle around kids and pets. Pennington 32-0-5 sits at the budget end with a high nitrogen number, so it stretches further per bag. Just respect that high N: apply lightly, never in the worst of summer disease season, and water it in.

Application Schedule by Texas Region (2026)

Texas is big enough that one calendar does not fit it. The right move is to tie your first feeding to soil temperature, not the date on the wall. St. Augustine wakes up and starts taking up nutrients when soil temps at the root zone hold around 65°F. Check your local reading with our soil temperature tool before that first spring application so you are not feeding dormant grass (which just feeds weeds). Here is how the season shakes out by region.

Gulf Coast and Houston

This is the Texas St. Augustine heartland: warm, humid, long growing season, often Floratam near the coast and Raleigh inland. Soil usually hits 65°F by late March. For a deeper local breakdown, see our Houston lawn care guide.

• Late March / early April: First feeding once growth is steady. PGF Complete 16-4-8 at about 1 lb N per 1,000 sq ft.
• Mid to late May: Second feeding. PGF Complete again, or Pennington 32-0-5 if you want more reach.
• Early to mid July: Ease off nitrogen. Use Milorganite 6-4-0 for color without pushing disease-prone growth in peak humidity.
• Late August / early September: Final main feeding for the year. PGF Complete or a balanced slow-release.
• Stop feeding nitrogen by late September. Late-season nitrogen invites fall brown patch (large patch).

East Texas (Tyler, Lufkin)

East Texas soils run sandy and acidic, so nitrogen leaches faster and the lawn benefits from more frequent, lighter feedings. The acidity also means iron is generally more available, so chlorosis is less of an issue than out west.

• Early April: First feeding once soil holds 65°F. PGF Complete 16-4-8.
• Late May: Second feeding, light rate. Because sand leaches, lean toward the 3 lb annual end split across more passes.
• Early July: Light summer feeding with Milorganite 6-4-0 to hold color.
• Late August: Final feeding. Espoma Organic All Season is a good fit here if you are building sandy soil.
• Stop by late September to avoid feeding fall fungus.

Central Texas (Austin, San Antonio)

This is the alkaline clay and caliche country, plus the region most likely to be under summer water restrictions. Two rules dominate here: favor slow-release so the lawn does not depend on heavy watering, and plan on iron for color rather than chasing green with more nitrogen.

• Early to mid April: First feeding. PGF Complete 16-4-8.
• Late May: Second feeding, plus a chelated iron application if you are seeing yellowing. Southern Ag Chelated Liquid Iron or Ironite II.
• July: Skip or minimize nitrogen during water restrictions. Use iron alone (Ironite II) to keep color without forcing growth you cannot water.
• September: Final light feeding once the worst heat breaks. Slow-release only.
• Iron as needed all season whenever the lawn pales between feedings. It is the high-pH fix.

Common Texas St. Augustine Problems

Problem: Chinch bugs (the Houston-area scourge)

Chinch bugs are the number one pest of Gulf Coast St. Augustine. They thrive in hot, dry, sunny spots and suck the juice out of the grass, leaving expanding yellow-to-brown patches that look like drought damage but do not recover with water. The big mistake is dumping nitrogen on it: lush, soft growth from over-fertilizing is exactly what chinch bugs love. Solution: keep nitrogen moderate in summer, lean on slow-release like Milorganite, water properly, and treat with an appropriate lawn insecticide if you confirm the bugs. Do the "tin can flotation" test or part the grass at the patch edge to spot them before reaching for chemicals.

Problem: Gray leaf spot

Gray leaf spot flares in hot, humid weather and is made dramatically worse by summer nitrogen. You will see small gray or tan lesions on the blades, and in bad cases the lawn looks scorched. Solution: back off nitrogen in the peak of summer (this is the single biggest lever), water in the early morning so blades dry fast, and avoid the fast-release high-N products in July and August. This is exactly why our schedule swaps to gentle Milorganite mid-summer.

Problem: Brown patch / large patch (fall)

As nights cool in fall, brown patch (large patch) shows up as roughly circular patches of thinning, off-color grass. Late-season nitrogen is the accelerant. Solution: stop nitrogen feeding by late September, water in the morning rather than the evening, and improve drainage in low spots. If you feed late to "get one more green push," you are usually feeding the fungus.

Problem: Iron chlorosis (yellowing on alkaline soil)

Classic Central Texas issue. The lawn yellows, especially newer growth, even though it is getting nitrogen, because the high-pH Blackland clay or caliche locks iron up where roots cannot get it. Solution: apply chelated iron, not more nitrogen. Southern Ag Chelated Liquid Iron greens it up fast, and Ironite II gives a longer granular feed. Chelated forms stay available in alkaline soil far better than cheap iron sulfate.

Problem: Take-all root rot

Take-all root rot attacks stressed St. Augustine, thinning the lawn in irregular patches and weakening the roots so the grass pulls up easily. It is worse on high-pH soil and where the lawn is overwatered. Solution: avoid pushing the pH higher, do not overwater, keep the grass healthy with steady slow-release feeding rather than feast-or-famine nitrogen, and consider a top-dressing of peat moss over affected areas to lower surface pH around the roots.

Application Tips for Texas Conditions

Getting the product right is half the job. The other half is how you put it down in Texas heat. A few rules keep you from burning the lawn or wasting fertilizer.

• Never exceed 1 lb of actual nitrogen per 1,000 sq ft in a single application. Split the annual total across the season instead of front-loading it.
• Water the fertilizer in with about a quarter inch of irrigation after applying granular products, unless rain is on the way. This moves nutrients to the roots and prevents leaf burn in heat.
• Do not fertilize a dry, stressed, or dormant lawn. Feeding grass that is sitting in drought stress can scorch it. Make sure the lawn is actively growing and reasonably watered first.
• Feed in the cooler part of the day, early morning or evening, especially mid-summer. Avoid spreading granular onto wet blades in full mid-day heat.
• Use a calibrated spreader and follow the product's setting. Guessing leads to stripes (over and under-applied rows) that show up for weeks.
• Respect water restrictions. In Central Texas summers, lean harder on slow-release and iron so the lawn is not dependent on water you may not be allowed to apply.
• Sweep granules off hardscape back onto the lawn. Fertilizer left on driveways and sidewalks washes into storm drains and does nothing for your grass.

One more Texas-specific note: if you laid new sod or plugs this season, go easy. Wait until new sod has knit down and started actively growing (usually a few weeks) before the first real feeding, and consider a gentle liquid like the Advanced 16-4-8 to feed without burning tender roots. New St. Augustine wants water and time more than it wants a heavy nitrogen hit.

Conclusion

Feeding St. Augustine in Texas comes down to a few durable principles: hit 3 to 5 lbs of nitrogen per 1,000 sq ft a year with a balanced slow-release around 16-4-8, split it into several feedings, ease off the nitrogen during the hot, humid, disease-prone heart of summer, and fix yellowing on alkaline Central Texas soil with iron instead of more nitrogen. Tie your first feeding to soil temperature, adjust the cadence to your region (more frequent and lighter on sandy East Texas, iron-forward on Central Texas clay, generous on the Gulf Coast), and you will keep that thick green carpet through the worst the state can throw at it.

For the national-level breakdown of products, rates, and timing across all climates, see our complete best fertilizer for St. Augustine grass 2026 guide. And if you are still not 100 percent sure your lawn is St. Augustine versus a look-alike like centipede or coarse Bermuda, snap a photo and run it through our free grass identifier before you buy a single bag. Feeding the right grass the right way is how you win the Texas summer.