Best St Augustine Fertilizer for Green, Healthy Grass

This site contains affiliate links to products. We may receive a commission for purchases made through these links.

If you have a St. Augustine grass lawn, you know this warm-season grass is a true beauty, with its lush, deep turf and eye-catching color. But let’s be real; maintaining such a stunning lawn requires effort. And the key to achieving a thriving St. Augustine grass lawn? Fertilizer.

Don’t worry, though. With just a few good cultural practices and the right high-quality lawn fertilizer, your St. Augustine grass will be the envy of the neighborhood.

So, get ready to roll up your sleeves, choose the best St. Augustine fertilizer from our list, and watch your lawn transform into a vibrant, healthy oasis. Let’s get started!

10 Best St Augustine Fertilizer Choices

The best fertilizer for St. Augustine grass lawns has one pound of nitrogen per 1000 square feet of superoxide dismutases (SODs). SOD, or turf, is the top layer of the soil on which the grass grows. Here is our list of fertilizers that meet that criteria and will work wonders for St Augustine.

Scotts Turf Builder Lawn Food – Best Overall

Scotts Turf Builder Southern Lawn Fertilizer for Southern Grass, 10,000 sq. ft., 28.12 lbs.

The Scotts Turf Builder Lawn Food is best for strengthening the roots of St. Augustine. The fertilizer helps the grass absorb water and nutrients. It contains all the nutrients necessary for the grass to withstand the weather and weeds. 

The phosphorus-free fertilizer is suitable for St. Augustine grass lawns that endure high temperatures or drought during the Summer. As a result, this nitrogen fertilizer is most suitable if you’re in Florida, Texas, or California

It has a good amount of slow-release nitrogen that helps the grass grow greener and thicker. You can use a drop spreader or a broadcast to apply the fertilizer.


Type: Granular

NPK Ratio: 32-0-10

Coverage: 5,000 square feet

Effective Period: 6 weeks

Time Release: slow-release

Why is this the Best Choice?

The Scotts fertilizer is our top pick, as it allows re-entering the lawn immediately after application. Another benefit is that the fertilizer is suitable for all grass types and is safe for kids and pets. 


We think the fertilizer should come in a bag that is easier to seal after use. It also doesn’t last too long compared to other lawn fertilizers of this type.

BioAdvanced 3-in-1 Weed and Feed – Best Weed n Feed

BioAdvanced 3-In-1 Weed and Feed for Southern Lawns, Granules, 12.5 lb, 5,000 Sq Ft

BioAdvanced 3-in-1 fertilizer is best suited to keep pests and weeds away from your St. Augustine. The fertilizer is made especially for southern lawns. Its formula kills weeds like dollar weed, clover, and dandelion. 

It acts as a herbicide to keep the weeds away and fertilize the grass with one application. The fertilizer includes pre- and post-emergent herbicides, which is why it is the best weed n feed fertilizer on the market.


Type: Granular

NPK Ratio: 35-0-3

Coverage: 5,000 square feet

Effective Period: 8 weeks

Time Release: slow-release

Why Is This a Good Choice?

The fertilizer is phosphorus-free, so you don’t have to worry about checking the phosphorus ban in your state. Plus, it kills many types of weeds and provides essential nutrients to the grass.


The biggest drawback of this weed n feed fertilizer is that it is a bit expensive. Plus, it is not available in all states. 

Simple Lawn Solutions – Best Liquid Fertilizer for St. Augustine

Maximum Green & Growth Fertilizer High Nitrogen 28-0-0 Liquid Lawn Food Spray Spring & Summer- Any Grass Type- Simple Lawn Solutions - Concentrated Quick & Slow Release Attached Sprayer (32 Ounce)

Simple Lawn Solutions fertilizer is a liquid that helps St. Augustine get the nutrients it needs to grow. It is suitable for all types of grass and is best for St. Augustine as it also treats nitrogen deficiencies. The fertilizer contains 70% quick-release and 30% slow-release nitrogen. 

The fertilizer is also economical, as you can refill this container with the liquid. If you don’t want to buy the container and spray again, pre-filled jugs of this liquid fertilizer are available. Nitrogen fertilizer is suitable for small to medium lawns


Type: Pre-mixed Liquid

NPK Ratio: 28-0-0

Coverage: 3,200 square feet

Effective Period: 4 to 6 weeks

Time Release: quick and slow-release

Why Is This a Good Choice?

The Simple Lawn Solutions comes ready to use! All you have to do is hook it to the hose and spray on the St. Augustine lawns. The sprayer is also preset to the correct spray ratio. 


The only drawback of this fertilizer is that it provides less coverage than other lawn fertilizers. So, if you want to fertilize a larger lawn of 5,000 to 10,000 sq. ft., using a liquid fertilizer will be a hassle. 

Pennington UltraGreen Starter Lawn – Best Fertilizer for new St Augustine Sod

Pennington UltraGreen Starter Lawn Fertilizer, 14 LBS, Covers 5000 sq ft

Pennington UltraGreen Starter Lawn Fertilizer is designed for new sod lawns, especially for St. Augustine, which grows only by laying sod or planting grass plugs. 

The St. Augustine grass fertilizer contains 5% iron to give the grass a lush green color. Besides that, the 7.8% slow-release nitrogen strengthens the grass and provides the nutrition it needs to grow. Apply the nitrogen fertilizer to your sod lawn before laying the sod strips for St. Augustine for the best results.


Type: Granular

NPK Ratio: 22-23-4

Coverage: 5,000 square feet

Effective Period: 12 weeks

Time Release: slow-release

Why Is This a Good Choice?

The granular starter fertilizer is a good choice for St. Augustine because it’s reasonably priced. It provides feed for up to 12 weeks. Plus, the fertilizer is suitable not only for a new lawn but for overseeding existing lawns too.


The fertilizer sometimes clumps up during application, which is annoying when spreading it on the grass.

Pennington UltraGreen Lawn Fertilizer – Best Summer Fertilizer

Pennington 100536576 UltraGreen Lawn Fertilizer, 14 LBS, Covers 5000 Sq Ft

We have another Pennington fertilizer on our list because it is among the best for the St. Augustine lawn. This one is best suited for Summer when the grass has to withstand extreme heat and drought

The best fertilizer for St. Augustine grass in Summer should contain iron to keep the grass deep, green, and healthy. This fertilizer contains 5% iron and 10.5% slow-release nitrogen to provide essential nutrients. 

These components keep the grass healthy and lush during extreme heat. The main feature of this Pennington UltraGreen Lawn Fertilizer is that it strengthens St. Augustine against heat and drought. 


Type: Granular

NPK Ratio: 30-0-4

Coverage: 5,000 square feet

Effective Period: 12 weeks

Time Release: slow-release

Why Is This a Good Choice?

The best thing about the Pennington UltraGreen Lawn Fertilizer is that it’s long-lasting. The product is relatively affordable and provides quick results. Plus, it helps St. Augustine survive the hottest temperatures.


One drawback of this fertilizer is that if you overfertilize, grass can be burned. Thus, you must be careful when applying fertilizer; otherwise, your beautiful St. Augustine will turn brown or burn away.

Advanced Simple Lawn Solutions Fertilizer – Best Winter Fertilizer

Advanced 16-4-8 Balanced NPK - Lawn Food Quality Liquid Fertilizer - Spring & Summer Concentrated Spray - Any Grass Type - Simple Lawn Solutions (32 Ounce)

For St. Augustine lawns, you shouldn’t fertilize them from December through February. But if your lawn is overseeded, you can fertilize it once or twice in the winter. The Simple Lawn Solutions liquid fertilizer is the best winter fertilizer for St. Augustine grass.

It will turn brown if you don’t care for your St. Augustine grass in winter. This fertilizer contains an NPK of 16-4-8, which is perfect for the Winter season. Besides St. Augustine, the fertilizer is suitable for many other grass types.


Type: Liquid

NPK Ratio: 16-4-8

Coverage: 5,000 square feet

Effective Period: 12 weeks

Time Release: slow-release

Why Is This a Good Choice?

The liquid fertilizer is very easy to apply. It also comes with a ready-to-use sprayer, which you can use to apply fertilizer easily on St. Augustine.


The fertilizer doesn’t give quick results, which might be problematic for those who want to quickly see their grass lush and healthy.

Super Juice Lawn Fertilizer – Best Spring Fertilizer

Super Juice All in One Soluble Supplement Lawn Fertilizer

The Super Juice Lawn Fertilizer is best suited for use during the Spring season. The fertilizer contains essential micronutrients, including magnesium, copper, zinc, manganese, sulfur, and 4% iron. 

This best fertilizer for St. Augustine grass in the Spring works quickly and lets nutrients get into the grass quickly. Besides that, the humic acid in this fertilizer also improves soil health


Type: Granular

NPK Ratio: 14-2-4

Coverage: 1,500 square feet

Effective Period: 3 weeks

Time Release: slow-release

Why Is This a Good Choice?

This fertilizer is a good choice for use in spring and summer. Another significant benefit of this fertilizer is that it is easy to mix and spread. 


The fertilizer is on the expensive side. There are other, more affordable options available for fertilizers of this size.

The Andersons Professional PGF Complete – Best Fall Fertilizer

The Andersons Professional PGF Complete 16-4-8 Fertilizer with 7% Humic DG 5,000 sq ft

The Andersons Professional PGF Complete is perfect for St. Augustine lawns in Fall and Winter. The patented technology in this fertilizer helps the nutrients reach the roots more quickly. Besides that, it contains all the micronutrients, including iron, to maintain that beautiful blue-green color of the grass. 

Using Humic DG technology, the fertilizer penetrates deep into the root to improve soil health. The slow-release nitrogen in this fertilizer keeps feeding St. Augustine continuously for up to 8 weeks


Type: Granular

NPK Ratio: 16-4-8

Coverage: 5,000 square feet

Effective Period: 8 weeks

Time Release: slow-release

Why Is This A Good Choice?

The Andersons Professional fertilizer is perfect for St. Augustine, giving fast results. You can get a lush green lawn within 6 to 14 days with proper watering and irrigation.


If you plan to use fertilizer containing phosphorus, it’s important to note that it is prohibited in some states. For example, if you reside in Washington, New York, New Jersey, or Minnesota, you won’t be able to use phosphorus fertilizer. Additionally, there are a handful of other states that also prohibit the use of phosphorus in fertilizer.

Milorganite Nitrogen Fertilizer – Best Organic

Milorganite All-Purpose Eco-Friendly Slow-Release Nitrogen 6-4-0 Fertilizer, for Lawns, Flowers, Gardens, 32 Pound Bag

Milorganite Nitrogen Fertilizer is an eco-friendly, slow-release fertilizer. It helps with root development and contains non-staining iron for a deep green color. The fertilizer is all-purpose, which means that besides St. Augustine, you can also use it on other plants.

The fertilizer is entirely organic and has ingredients that enhance the soil structure. The micronutrients in this fertilizer benefit the microorganisms, so St. Augustine grows well. 


Type: Granular

NPK Ratio: 6-4-0

Coverage: 2,500 sq. ft.

Effective Period: 10 weeks

Time Release: slow-release

Why Is This a Good Choice?

The best thing about this fertilizer is that it is environmentally friendly. Plus, it is very affordable and gives long-lasting results. 


The Milorganite fertilizer doesn’t contain potassium, so it’s unsuitable for winter use. Plus, it might be challenging to use the fertilizer in states which have banned phosphorus.

Miracle-Gro Lawn Food – Best Fertilizer for Yellow St Augustine Grass

Miracle-Gro® Water Soluble Lawn Food, 5 lb.

If your St. Augustine is turning yellow, it’s probably going through an iron and nitrogen deficiency. This fertilizer is packed with a high nitrogen content that enriches the color of St. Augustine and promotes dense growth.

The granulated fertilizer is specially designed for turfgrass and feeds the grass blades and roots. This is why Miracle-Gro Lawn Food works on the yellow St. Augustine to bring back the natural grass. 


Type: water-soluble granules

NPK Ratio: 30-0-6

Coverage: 1,800 sq. ft.

Effective Period: 4 to 6 weeks

Time Release: slow-release

Why Is This a Good Choice?

This is a good choice as it contains water-soluble granules. The application is easy because you don’t need a pump-type garden sprayer. 


The application directions on the fertilizer pack should be more detailed and accurate. Besides that, another drawback is that the fertilizer works best with a garden feeder that is sold separately.

Best NPK for St Augustine Grass

Best fertilizer ratio for st augustine grass

When choosing the best fertilizer for your St. Augustine grass, NPK is a crucial factor to consider. NPK stands for the nitrogen, phosphorus, and potassium content in a fertilizer, also known as macronutrients, essential for healthy plant growth.

Perform a Soil Test to Know the Right NPK for Fertilizing

To determine the correct NPK ratio for your St. Augustine grass, it’s vital to perform a soil test to understand the macronutrient content already present in the soil.

For example, if you live in Florida, where the soil has a lot of phosphorus on its own, you should use a fertilizer with less phosphorus.

If you haven’t yet tested your soil, a nitrogen-only fertilizer with an NPK ratio of 3-1-2, such as a 21-0-0 fertilizer, is a good option. You could also consider a low-phosphorus fertilizer with an NPK of 15-0-15 or 21-3-6.

Consider the Season

It’s also crucial to consider the season and weather conditions when choosing the right NPK ratio. For example, during the summer (June to August), a nitrogen-rich fertilizer with low phosphorus is recommended.

In contrast, a fertilizer high in potassium would be more beneficial in winter. In spring, a 10-10-10 fertilizer would be ideal for St. Augustine grass.

For best results, you should fertilize St. Augustine grass with an NPK ratio of 16-4-8. This slow-release fertilizer contains 16% nitrogen, 4% phosphorus, and 8% potassium, providing sustained nourishment to your grass over an extended period. If your soil is sandy, a nitrogen-rich fertilizer would be particularly beneficial.

When is the Best Time to Fertilize St. Augustine Grass?

St augustine fertilizer schedule

The best time to fertilize St. Augustine varies from state to state. In general, the best time to fertilize St. Augustine grass lawns is three weeks after the grass starts turning green.

Have a look at the following to know more about the best fertilizing times for St. Augustine in these states:

  • Texas: April to September
  • Florida: Early May to Early July
  • California: Early May to Early July
  • Louisiana: Mid-Spring to Summer
  • Georgia: Once in early Spring, again in August
  • Houston: Between April and September

How Often Should You Fertilize St. Augustine?

To maintain a healthy St. Augustine lawn, it’s recommended to fertilize it 2 to 6 times a year, depending on your location. If you have recently laid new sod, you should start fertilizing three weeks after the grass has turned green.

For optimal results, apply 1 ½ pounds of slow-release nitrogen per 1000 sq. ft. every ten weeks. Alternatively, you can use 1 pound of soluble nitrogen per 1000 sq. ft. every eight weeks.

It’s best to avoid fertilizing your St. Augustine grass from December to February unless you have overseeded your lawn. If your lawn is overgrown, you can fertilize it once in December and again in February.

Following this St. Augustine fertilizer schedule will promote healthy growth and lawn thickness.

Choosing a Fertilizer Formula

Liquid fertilizer for st augustine

Besides looking at the NPK ratio of fertilizer, there are several other factors that contribute to getting the right fertilizer formula for your St. Augustine:

Liquid vs. Granular

A granulated fertilizer feeds lawns slowly since it’s a slow-release formula. The most significant advantage of using granular fertilizers is that they don’t require frequent application. After application, they provide nutrients to the grass for many weeks.

On the other hand, liquid fertilizers are easy to apply but require more frequent application. They provide quicker results compared to granular fertilizers.

Another type of fertilizer is water-soluble fertilizers, which resemble granular fertilizers but dissolve quickly in water and provide fast-acting results.

Slow Release vs. Quick Release

Quick-release fertilizers offer rapid results but require more frequent applications. Slow-release fertilizers provide sustained nourishment for an extended period.

Organic vs. Synthetic

Organic fertilizers are more eco-friendly and provide long-term benefits to the soil. However, they offer slower results and have a more pungent smell than synthetic fertilizers.

Synthetic fertilizers provide quicker results but are less eco-friendly. Sandy soils may benefit from organic fertilizers such as composted manure, which contains more nutrients.

Frequently Asked Questions About St Augustine Grass

Best fertilizer for st augustine grass in california

How do I make my St Augustine grass thicker?

To thicken your St. Augustine grass, start by ensuring proper soil drainage and a pH range of 5 to 8.5. Plant sods or plugs in early summer and apply a high-quality, nitrogen-rich fertilizer. Mow at the appropriate time to promote thickness.

Can I use Miracle-Gro on St Augustine grass?

Yes, you can safely use Miracle-Gro fertilizer for St. Augustine grass. However, for fungus issues, a different fungicide should be used.

How do you encourage St Augustine to spread?

Encourage St. Augustine grass to spread by using stolons, mowing less frequently, watering more often, and using a nitrogen-rich fertilizer containing phosphorus for good root growth.

How do you fix bare spots in St Augustine grass?

To fix bare spots in St. Augustine grass, remove the dead grass using a rake, plant new sods or plugs, and continue to water and feed the grass for proper growth.

How do you fix St Augustine grass that is thinning?

To fix thinning St. Augustine grass, ensure it receives proper nutrition and water, treat pests if necessary, adjust mowing habits, and use a high-quality fertilizer for St. Augustine grass.

Is Scotts Turf Builder good for St Augustine grass?

Yes, Scotts Turf Builder is one of the best fertilizers for St. Augustine grass. It’s specifically designed for Southern lawn types, including St. Augustine, Zoysiagrass, Centipedegrass, and Carpetgrass.

What causes dead circles in St Augustine grass?

Dead circles in St. Augustine grass are caused by overfertilizing with a fertilizer that is too high in nitrogen content. Excess nitrogen can cause brown patches and burn the grass, resulting in dead circles.

Can you over-fertilize St Augustine grass?

Yes, St. Augustine grass can get too much fertilizer if it gets it more often or in larger amounts than is recommended. Over-fertilization can lead to nitrogen burning, causing the grass to turn yellow and resulting in faster blade growth but not necessarily healthier grass.

Maintaining Your St Augustine Grass Year Round

To achieve a lush and dense St. Augustine lawn, start with a soil test to determine the right fertilizer. If you need help deciding what fertilizer to use, seek advice from a professional. Store the fertilizer in a dry place and apply it with a broadcast spreader.

Here are some tips to maintain and boost the color of your St. Augustine lawn all year round:

  • Watch for signs of pests such as white grubs and chinch bugs.
  • Keep St. Augustine grass tall. Set your mower’s setting to 3 inches in the shade or 2 ½ inches in the sun.
  • Choose herbicides carefully, as St. Augustine grass is sensitive to a few weed control products.
  • Water the grass every 5 to 10 days, checking for signs of drought such as folded or rolled leaves and a dull bluish color.
  • Water the grass periodically during winter, even though it’s dormant during this season.
Special offer for our visitors

Get your Free Garden Guide

We will never send you spam. By signing up for this you agree with our privacy policy and to receive regular updates via email in regards to industry news and promotions