The Best Fertilizers for St. Augustine Grass (+ What Type of Lawn Fertilizer to Use)

Kenneth Wilson

It is easy to be a big fan of St. Augustine grass lawns due to their attractiveness and high resistance. But to achieve this, you must follow proper maintenance to achieve a picture-perfect lawn. This maintenance involves picking the correct fertilizer and following its right application frequency and schedule.

If you want a healthy, green lawn– we've compiled our top picks for the best fertilizer for St. Augustine grass. (Related: The Best Fertilizers for a Lush, Green St. Augustine Grass Lawn)

122 Ratings

This lawn fertilizer from Pennington is known for its rich nitrogen content and 5% iron– helping your lawn take on a deep, green color in under a month.

7 Ratings

It is fortified with iron and other vital micronutrients, so its slow-release granules are impressive in lawns with sloped areas and lacking soil nutrients.

0 Rating

It has equal nitrogen and potassium, so it encourages improved new blade formation, a vibrant color, and strong root development.

157 Ratings

Its formula encourages stronger and deeper root development, making it more tolerant of extreme conditions.

2,344 Ratings

With its all-purpose formula, you can use it for other plants in your yard apart from your St. Augustine grass.

749 Ratings

it has a high-nitrogen formula, so it can keep the turfgrass thick and bright green in the late summer and spring months.

2,207 Ratings

This product has micronutrients such as copper, magnesium, zinc, and 4% iron, promoting healthy soil growth.

In This Review & Buyers Guide

7 Best Fertilizer for St. Augustine Grass

If you’re currently browsing Google on “What is the best fertilizer for St. Augustine grass,” we’ve compiled some of the top picks in the market today.


This lawn fertilizer from Pennington is known for its rich nitrogen content and 5% iron– helping your lawn take on a deep, green color in under a month. Aside from its quick green-up feature, your lawn can benefit from continuous feeding thanks to the fertilizer's slow-release nitrogen formula.

The UltraGreen is ideal for St. Augustine grass lawns in the southern regions, as it helps your turf withstand extreme heat and drought conditions.

Product Specifications


  • Fertilizer type: Granular
  • NPK ratio: 30-0-4
  • Time release: Immediate-release and slow-release
  • Product size: 14 lbs.
  • Coverage area: 5,000 sq. ft.

This next fertilizer for St. Augustine grass is an excellent choice if you already have an established lawn in phosphate-restricted zones. Since it has equal nitrogen and potassium, it encourages improved new blade formation, a vibrant color, and strong root development.

Additionally, it contains humic acid, which supports macronutrient uptake and improves the general health of your turf. We're big fans of its simple usage, as it comes with a hose-end spray attachment that only needs flushing out after every use. It can be ready to use from the container itself.

Product Specifications


  • Fertilizer type: Pre-mixed Liquid
  • NPK ratio: 15-0-15
  • Application method: Hose end spray
  • Coverage area: 3,200 sq. ft.

Advantages


  • It is an excellent choice in phosphate-restricted zones
  • It provides fair support that encourages strong root formation and a vibrant color

This nitrogen fertilizer from Milorganite is a popular eco-friendly choice made from recycled nutrients. Unlike its synthetic counterparts, the organic matter found in the fertilizer is known to significantly improve the soil structure and benefit microorganisms in the ground, such as bacteria and earthworms. This helps aid healthy grass growth.

This fertilizer is also relatively more cost-efficient than other organic fertilizers today. With its all-purpose formula, you can use it for other plants in your yard apart from the St. Augustine grass.

Product Specifications


  • Fertilizer type: Granular
  • NPK ratio: 6-4-0
  • Time release: Slow-release
  • Product size: 32 lbs.
  • Coverage area: 2,500 sq. ft.

The Super Juice fertilizer is a balanced choice for St. Augustine grass lawns. It has a 14-2-4 NPK ratio, a good combination of Nitrogen, Phosphorus, and Potassium. (Note: Homeowners who want to use it at full strength can do so at a ratio of 14-2-4. Meanwhile, the ratio is at 7-1-2 for half-strength use.)

It is available in a dry mix formula, so you won't have to go through tremendous trouble during application. Mix it with water and directly spray it on your lawn, allowing you to apply even coatings. This product has micronutrients such as copper, magnesium, zinc, and 4% iron, promoting healthy soil growth.

Advantages


  • It is easy to mix and spread on your lawn evenly
  • It can be used with either full or half-strength, depending on your need
  • This fertilizer contains micronutrients such as magnesium, iron, and zinc

It's always best to do a soil test on your lawn to reveal its current condition. And once it shows signs of poor soil– you can opt to use Andersons Fertilizer With Humic 16-4-8, which is a professional-grade option.

This gives your soil adequate phosphorus to revitalize the worn-out root systems and encourage new growth. It is fortified with iron and other vital micronutrients (humic and fulvic acids), so its slow-release granules are impressive in lawns with sloped areas and lacking soil nutrients.

Given good rainfall and watering, you can expect a greener, thicker St. Augustine lawn in as little as 6 to 14 days. This fertilizer gives a big bang for your buck, with a coverage of up to 10,000 sq. ft.

Product Specifications


  • Fertilizer type: Granules
  • Application: Push spreader
  • NPK ratio: 16-4-8
  • Coverage area: 5,000 sq. ft.

Advantages


  • It has ultra-fine pellets that ensure a more effective coverage
  • It has a slow-release formula to ensure a consistently greener lawn

The Scotts Turf Builder Southern Lawn Food makes for an excellent fertilizer choice for lawns in the Southern regions, as they need to withstand high temperatures and extended periods of drought.

Its formula encourages stronger and deeper root development, making it more tolerant of extreme conditions. Since it has a high slow-release nitrogen formula, it will help your St. Augustine grass grow greener and thicker faster. The Scotts brand also patented the All-in-One Particles technology, evenly distributing nitrogen and other nutrients to avoid burning the lawn.

Product Specifications


  • Fertilizer type: Granular
  • NPK ratio: 32-0-10
  • Time release: Slow-release
  • Product size: 14 lbs.
  • Coverage area: 5,000 sq. ft.

This next fertilizer helps St. Augustinegrass lawns survive intense summers, especially in the south. It also works as a pre- and post-emergent herbicide to eliminate weeds on your lawn. After application, it can also prevent weeds from taking over your yard for the next six months.

Since it has a high-nitrogen formula, it can keep the turfgrass thick and bright green in the late summer and spring months. Avoid overfertilizing your lawn, as adding excessive nitrogen may only kill off your turfgrass.

Product Specifications


  • Fertilizer type: Granular
  • NPK ratio: 35-0-3
  • Time release: Slow-release
  • Product size: 12.5 lbs.
  • Coverage area: 5,000 sq. ft.

Frequently Asked Questions (FAQs)

How should I fertilize St. Augustine grass?

Your St. Augustine lawn's age and condition determine how to fertilize it. Do you have freshly sown grass, newly laid sod, or an established one? New grass seeds require more phosphorus to promote robust, healthy root systems. When established, a nitrogen-rich lawn feed will give your grass that lush, green appearance that can withstand stress. To avoid damaging St. Augustine seedlings, avoid applying weed-and-feed products on them. It's not advisable by experts because they can badly harm delicate grasses while promoting rapid growth in any weeds already present. (Related: 5 Tips on How to Keep your St. Augustine Grass Healthy and Fresh in Florida)

How often should I fertilize St. Augustine grass?

Depending on the application procedure, the frequency will vary. St. Augustine grass should be fertilized around every 6 to 8 weeks when using a liquid alternative. Spreading granules is only necessary once or twice per season. A good soil test will determine how much to apply. Use this to identify which nutrients the soil currently has and which are lacking.

How should I apply fertilizer to St. Augustine grass?

Shortly after the first spring mowing is the time to apply liquids; immediate root absorption will promote lush, fresh growth. Just go over your yard while using even rows of spray. Drops or broadcast spreaders are used to apply granules. On the label of every product, there should be a suggested spreader setting.

When should I fertilize St. Augustine grass?

After the last anticipated frost in spring, successful fertilization begins using a low nitrogen/high phosphorus fertilizer. Transitioning to high nitrogen throughout the summer will direct energy into the production of thick, strong blades. Iron will increase the color of the green without promoting excessive growth. Nitrogen fertilizer applications in the fall might promote new growth that an early frost could fatally damage. However, potassium is advised to enhance winter resilience.

Kenneth Wilson
July 25, 2022
2terra, Reviews, Yard & Garden

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done. I also operate remodeling design service for homeowners.

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