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Warm-season St. Augustine lawns need different feeding strategies once temperatures climb. Using the right fertilizer for St. Augustine in summer helps maintain color, reduces drought and heat stress, and limits unnecessary growth that can weaken grass when hot weather persists. This guide shortlists five well-suited fertilizers for summer care and explains how we evaluated each option for nutrient balance, slow-release behavior, and stress tolerance. Read on to compare the products and learn the practical criteria that matter for summer applications.
Top Picks at a Glance
| Best Overall The best all-around choice for most situations | TPS Nutrients St. Augustine Liquid Lawn Fertilizer, 32 oz |  |
| Best Quality Built to a higher standard if you want something more solid | LESCO 50 lb. St. Augustine Grass Weed and Feed (Penoxsulam) |  |
| Best Budget The cheapest option that still gets the job done reliably | TPS Nutrients St Augustine Liquid Lawn Fertilizer, 8 fl oz |  |
| Highest Rated A top-rated pick with lots of positive feedback | Ferti-lome Centipede Lawn Fertilizer 15-0-15, 16 lb |  |
| Best Seller A high-volume bestseller chosen again and again | Ferti-lome St. Augustine Weed & Feed 15-0-4 (25.6 lb) |  |
TPS Nutrients St. Augustine Liquid Lawn Fertilizer, 32 oz
| Item Form | Liquid |
|---|---|
| Application Method | watering can or hose-end sprayer |
| Target Species | St. Augustine Grass |
| Liquid Volume | 32 fluid ounces |
This TPS Nutrients liquid fertilizer is made for St. Augustine lawns and delivers nitrogen-rich nutrition in a quick-absorbing, water-diluted form. It is applied with a watering can or hose-end sprayer so you can treat bare spots and established turf with targeted feeds rather than broadcasting granular product. The formula emphasizes fast nutrient delivery to green up color and encourage new runners while supporting deeper roots for better heat and wear tolerance. For budget-conscious gardeners the concentrated liquid means you can spot-treat problem areas and see visible results faster than many slow-release granules. Limitations are that coverage is listed as low, so a single 32 oz bottle will not service large lawns and frequent applications may be needed to maintain color; it also requires correct mixing and hose-end setup to avoid uneven application. If you want a quick, easy liquid boost tailored to St. Augustine grass, this product is a practical choice for small yards and targeted treatments.
Best for: Homeowners with small to medium St. Augustine lawns who want a fast, targeted green-up and prefer easy hose- or can-applied treatments while watching their budget.
Less Ideal for: Owners of large turf areas or those who prefer one-time, long-duration granular feeding should consider higher-coverage granular fertilizers instead.
- Formulated specifically for St. Augustine grass to target species needs
- Fast-absorbing liquid delivers quicker visible green-up than many granules
- Works with watering can or hose-end sprayer for spot treatments and easy application
- Supports root growth and new runners to improve turf density
- Coverage is low so one 32 oz bottle is insufficient for large lawns
- Liquid requires proper mixing and application to avoid streaking or uneven results
Verdict: A compact, species-specific liquid fertilizer that gives fast visible green-up and targeted root support for small St. Augustine lawns.
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.
TPS Nutrients St Augustine Liquid Lawn Fertilizer, 8 fl oz
| Item Form | Liquid |
|---|---|
| Application Method | watering can or hose-end sprayer |
| Coverage | Low |
| Liquid Volume | 8 fluid ounces |
| Target Species | Lawn Grass |
This 8 ounce liquid formula from TPS Nutrients is designed specifically for St. Augustine grass and is applied with a watering can or hose-end sprayer. It delivers a fast-absorbing, high-nitrogen feed that encourages rich green color, new runners, and stronger root development for improved drought and wear tolerance. Typical use is a diluted application over small to medium patches or spot treatments where quick color and growth response is desired; the liquid form makes mixing and immediate feeding straightforward. Notable features include its turf-targeted formulation, compatibility with common application tools, and small concentrated bottle convenient for occasional treatments or trial use. Because the listed coverage is low and the bottle holds only 8 fluid ounces, this product is best for targeted feeding rather than treating large lawns repeatedly. Expect quick visible results in color and vigor, but plan on multiple purchases or a larger-format product if you have extensive turf to maintain.
Best for: Buyers who want a turf-specific, fast-acting feed to revive patchy or pale St. Augustine lawns and who prefer liquid applications for spot treatment or seasonal boosts.
Less Ideal for: Homeowners with large acreage or those seeking a long-lasting, single-application fertilizer should consider larger-volume or slow-release granular products instead.
- Liquid, fast-absorbing formula for quick visible color and growth
- Designed for St. Augustine turf with a high-nitrogen focus to promote new runners and thicker swards
- Works with common application methods: watering can or hose-end sprayer
- Small concentrated bottle is convenient for spot treatments or trialing on a new lawn
- Low stated coverage and small 8 fl oz volume make it impractical for large lawns without frequent repurchase
- No granular slow-release option for long-term feeding
Verdict: A compact, high-nitrogen liquid made to deliver fast green-up and thicker growth for St. Augustine lawns in need of targeted, quick results.
Ferti-lome Centipede Lawn Fertilizer 15-0-15, 16 lb
| Analysis | 15-0-15 |
|---|---|
| Form | Granules |
| Coverage | 5000 |
| Target Species | Centipede, St. Augustine, Bermuda, Zoysia and other warm-season grasses |
| Unit Count | 256 Ounce |
This granular 15-0-15 fertilizer is designed for warm-season lawns such as St. Augustine and delivers slow-release nitrogen plus potassium to improve color and general turf vigor. You apply it with a broadcast or drop spreader at the label rate (about 4 lb per 1,000 sq ft) in early spring and early fall; a single 16 lb bag covers roughly 5,000 sq ft at the specified rate. The slow-release nitrogen lowers the chance of burning while providing sustained greening, and the added iron helps correct yellowing quickly. Practical benefits include straightforward application, predictable nutrient numbers for planning a feeding schedule, and suitability for a variety of warm-season species. Limitations are that it contains no phosphate so it will not address root establishment needs, and a single bag is modest for larger lawns so frequent purchases or larger bags may be needed for regular maintenance. Standard handling precautions apply to keep pets and children away until granules are settled or watered in.
Best for: Homeowners maintaining established St. Augustine and other warm-season lawns who want an affordable, easy-to-apply fertilizer that improves color without aggressive quick-release nitrogen.
Less Ideal for: People establishing new lawns, overseeding, or needing a fertilizer with phosphorus for root development should choose a different product.
- Formulated 15-0-15 with slow-release nitrogen to reduce burn risk while greening turf
- Contains added iron to help correct yellowing quickly
- Granular form works with standard spreaders for even application
- Coverage claim of up to 5,000 sq ft at label rate simplifies planning for small to medium lawns
- No phosphate included so it will not promote root development after seeding or sod
- 16 lb bag may be small for larger properties requiring frequent repurchase
Verdict: A cost-conscious, easy-to-apply slow-release 15-0-15 granular fertilizer that reliably greens established St. Augustine and other warm-season lawns.
Ferti-lome St. Augustine Weed & Feed 15-0-4 (25.6 lb)
| NPK | 15-0-4 |
|---|---|
| Form | Granules |
| Coverage | 5,000 sq. ft. |
| Specific Uses For Product | Lawns (Centipede, Zoysia, St. Augustine) |
This weed-and-feed product combines a 15-0-4 fertilizer with an atrazine-containing herbicide to prevent and control common weeds in St. Augustine, Zoysia, and Centipede lawns while feeding turf. You spread the granules across the lawn according to label rates (one bag covers roughly 5,000 sq. ft.) typically in early spring, and the formulation offers season-long weed defense plus nutrient input in a single application. Practical benefits include targeted compatibility with warm-season grasses listed on the label and the convenience of a combined treatment instead of separate fertilizer and herbicide steps. Important limitations are that it is not labeled for use on Bermuda or northern grasses and contains a chemical active ingredient that some gardeners avoid, so read and follow the label closely and take standard safety precautions when applying. For homeowners wanting a straightforward, one-pass option to both feed and reduce weeds on listed turf types, this product simplifies maintenance but requires attention to proper timing and lawn type compatibility.
Best for: Homeowners with St. Augustine, Zoysia, or Centipede lawns who prefer a cautious, single-product approach to both fertilizing and weed control and prioritize following label directions.
Less Ideal for: Gardeners with Bermuda or cool-season lawns or those seeking organic or chemical-free solutions should choose a different fertilizer or weed control method.
- Combined pre-emergent and post-emergent weed control plus fertilizer in one product
- Formulated specifically for St. Augustine, Zoysia, and Centipede grasses
- Covers approximately 5,000 square feet per bag for yard-scale application
- Granular form is easy to apply with a broadcast spreader
- Contains atrazine which some users avoid for environmental or safety reasons
- Not safe for Bermuda or northern grass varieties so misuse can damage lawn
Verdict: If you have an eligible warm-season lawn and want a simple one-step product to feed turf and control weeds, this St. Augustine weed-and-feed delivers both in a single application.
Choosing the Right Fertilizer for St. Augustine in Summer: Key Factors to Consider
Nitrogen Source and Release Pattern
Summer feeding should favor slow-release nitrogen over quick-release forms. Slow-release sources feed turf gradually, reducing the flush of tender growth that can be damaged by heat and drought. They also lower the chance of foliar burn if the lawn is stressed from lack of water.
Check packaging for terms like controlled-release, polymer-coated, or stabilized nitrogen. The proportion of water-soluble nitrogen to slow-release nitrogen influences how quickly turf will respond after application, so choose a higher slow-release share for midsummer use.
Potassium Content for Heat and Drought Resilience
Potassium helps grass regulate water and improves cell strength during heat stress. A fertilizer with adequate potassium will not force excessive top growth but will support root function and recovery from scorching.
Look at the middle number in the guaranteed analysis and favor blends that raise potassium relative to nitrogen during summer applications. That helps the lawn tolerate brief dry spells and recover faster after irrigation or storms.
Micronutrients and Turf Color
St. Augustine often shows visual improvement from iron and other micronutrients that deepen green color without stimulating excessive leaf growth. Micronutrient balance matters most if soil tests show deficiencies or if the lawn displays chlorosis despite adequate nitrogen.
Micronutrients are typically included in modest amounts; avoid mixes that overload micronutrients because imbalances can interfere with nutrient uptake. Foliar iron products can be used as a supplement between granular feedings when quick color boost is needed.
Application Method and Timing
Granular fertilizers are common for home lawns because they are easy to spread evenly with a broadcast or drop spreader. Liquid or foliar feeds deliver nutrients quickly but require more frequent applications. For summer use, choose a method that matches how often you can irrigate and your tolerance for frequent treatments.
Apply in the cooler parts of the day and water-in lightly if the product label recommends it. Avoid mowing immediately after application if broadcast particles could be ground into clippings that smear on turf.
Burn Risk and Safety Margins
High soluble nitrogen or improper application rates increase the risk of fertilizer burn, especially when turf is heat-stressed. Products with high salt indexes or predominantly fast-release nitrogen are more likely to cause leaf scorch during summer.
Follow label rates for St. Augustine and err on the conservative side if the lawn is under drought stress. Consider using a split-application approach with smaller doses spaced over several weeks to keep turf fed without overloading it.
Compatibility With Soil and Irrigation Practices
Soil texture, pH, and existing fertility affect how a fertilizer performs. Sandy soils leach nutrients faster and may benefit from slower-release formulations or more frequent, lighter applications. Heavy clay can retain nutrients longer but may need potassium adjustments for uptake.
Also consider irrigation frequency. If you water deeply and infrequently, a slow-release granular product that stays available between waterings is usually a better match than a soluble, quick-release fertilizer that requires regular irrigation to avoid uneven uptake.
When to Apply Fertilizer During Summer
Timing matters more in summer than in milder seasons. Apply fertilizers in early morning or late evening to avoid the hottest part of the day. That reduces immediate volatilization and decreases the chance of scorch on wet leaves exposed to direct sun.
For established St. Augustine, many gardeners use lighter, more frequent applications rather than a single heavy feeding. Spacing applications every 4 to 6 weeks with moderate rates helps maintain color while limiting tender growth that struggles in the heat.
- Avoid fertilizing during prolonged drought or heat waves; wait for cooler, moister conditions.
- If you must fertilize, split the recommended rate into two smaller applications.
- Water after application only as directed to activate slow-release granules or to move soluble nutrients into the root zone.
Interpreting a Soil Test for Summer Feeding
A soil test is the most reliable way to set a summer feeding plan. It reveals pH and available nutrients so you can choose a fertilizer that corrects actual deficiencies rather than guesswork. For example, if potassium is low, prioritize a blend higher in potassium for stress resilience.
Without a test, follow conservative feeding guidelines and consider a balanced slow-release lawn fertilizer formulated for warm-season grasses. Overapplication can cause nutrient imbalances and environmental runoff during summer storms.
- Collect samples from multiple lawn areas for a representative test.
- Follow local extension recommendations for target nutrient levels in your region.
Watering Strategy After Fertilizer Application
Irrigation interacts with fertilizer choice. Light irrigation after applying many granular products helps dissolve and move nutrients into the root zone. However, heavy watering or runoff can waste nutrients and increase burn risk if soluble nitrogen is present.
Match your watering schedule to the fertilizer type: water more predictably for soluble feeds and less frequently for controlled-release products that need only occasional activation. Adjust irrigation to encourage deeper rooting, which improves heat tolerance.
- Avoid saturating the lawn immediately after application; follow label instructions.
- Use short cycles to reduce runoff on slopes, then allow the soil to absorb nutrients before additional watering.
Managing Common Summer Problems With Targeted Feeding
Thin, pale turf often benefits from a modest nitrogen dose plus iron rather than a heavy nitrogen application. Targeted feeding can correct visual issues without promoting weak, succulent growth that succumbs to heat.
For lawns showing patchy damage from chinch bugs or fungal stress, feeding alone will not fix the underlying issue. Use feeding to support recovery after pests or disease are controlled, focusing on potassium and overall plant vigor.
- Use iron to correct yellowing without boosting top growth.
- Prioritize recovery-focused feeding after stress events rather than aggressive greening attempts.
Storage and Handling in Hot Weather
Fertilizer stability can decline if bags are stored in extreme heat or humidity. Keep unopened bags in a cool, dry place and reseal partial bags to limit exposure. Damp storage increases clumping and can alter product performance.
When handling granules on hot pavement or driveways, be mindful that spilled fertilizer can cause temporary turf damage if concentrated. Sweep up spills promptly and avoid applying on scorching days when turf is already heat-stressed.
- Store fertilizers off concrete in a shaded area or inside a shed.
- Use gloves and a mask when handling dusty or powdered formulations.
How We Chose the Best Fertilizer for St. Augustine in Summer
We focused on fertilizers formulated to support St. Augustine grass during high temperatures and summer drought conditions. Selection started with products whose guaranteed analysis matched common summer needs for warm-season turf: modest nitrogen with emphasis on slow-release sources, balanced potassium for stress tolerance, and appropriate micronutrients such as iron for color without excess vegetative surge. We prioritized granular and controlled-release formulations that reduce rapid top growth and burn risk in heat. Application flexibility was also important, including compatibility with typical broadcast spreaders and clear label guidance for warm-season turf. Real-world handling factors such as ease of application, dust levels, and storage stability in warm garages were considered. Exclusions included products designed solely for spring green-up, winterizer blends, or specialty mixes for entirely different grass species. Final picks reflect a mix of slow-release nutrient delivery, heat-stress support, and predictable turf response.
FAQ
Can I apply a regular spring fertilizer in summer to speed up green-up?
Usually you should avoid spring-specific high-nitrogen formulations in summer. Spring fertilizers often have high water-soluble nitrogen that forces rapid growth and increases burn risk during heat. Choose a summer-appropriate, slow-release blend or reduce the rate significantly if a spring mix is the only option.
How often should I fertilize St. Augustine during hot months?
Frequency depends on the product. Slow-release granular fertilizers can be applied every 6 to 8 weeks, while lighter soluble feeds might be used every 3 to 4 weeks at reduced rates. In extreme heat or drought, delay feeding until conditions moderate.
Will adding iron solve yellowing in summer?
Iron can quickly improve green color if the yellowing is due to iron deficiency or marginal chlorosis. However, if the yellowing stems from heat stress, overwatering, or pests, iron alone will not resolve the root cause. Use iron as a supplement, not a substitute for proper cultural care.
Can fertilizer burn my St. Augustine lawn in summer?
Yes. Fertilizer burn is more likely when high rates or fast-release nitrogen are applied while the grass is drought-stressed or during heat waves. Use conservative application rates, prefer slow-release nitrogen, and follow label irrigation recommendations to reduce burn risk.
Should I change my fertilizer choice based on regional climate within the same summer?
Often yes. Humid coastal areas and inland hot-dry regions place different stresses on St. Augustine. In drier regions, prioritize slow-release formulas and higher potassium. In humid zones, balance nitrogen with disease-resistance strategies. Local extension guidance helps refine choices.
Final Verdict
For midsummer care, prioritize fertilizers that support stress tolerance rather than rapid top growth. Look for slow-release nitrogen, sufficient potassium, and modest micronutrients to maintain color without encouraging vulnerable succulent growth. Match your choice to soil test results, irrigation habits, and regional climate. By balancing nutrient release and application timing, you can keep St. Augustine lawns greener and more resilient through the heat.
