7 Best Fertilizer for St. Augustine Grass [High Nitrogen, Liquid + Granular]

To feed St. Augustine grass for a lush lawn, you want to apply a fertilizer that has high nitrogen content as well as other ingredients such as iron for quick greening. Both granular and liquid fertilizers are good for your St. Augustine lawn.

Similarly, organic and synthetic products can produce quick greening, but with organic, slow-release nitrogen fertilizer, you won’t run the risk of burning your lawn. After sample-testing 23 different fertilizers, here are the 7 best fertilizers for St. Augustine grass.

BEST LIQUID
Extreme Grass Growth Lawn Booster- Liquid Spray Concentrated...
BEST GRANULAR
LESCO 50 lb. St. Augustine Grass Weed and Feed with Penoxsulam
Simple Lawn Solutions Extreme Grass Growth Lawn Booster
Lesco Professional
  • Has humic acid for lawn soil health .
  • High nitrogen content for a thicker lawn.
  • 16-4-8 N-P-K greens quickly in about 7 days.
  • 100% natural liquid fertilizer.
  • Feeds for deep greening in just 3 days .
  • 2-in-1 formula feeds your St. Augustine adequately.
  • 16-4-8 N-P-K high nitrogen great for St. Augustine lawns
  • Other N-P-K ratios are available.
BEST LIQUID
Extreme Grass Growth Lawn Booster- Liquid Spray Concentrated...
Simple Lawn Solutions Extreme Grass Growth Lawn Booster
  • Has humic acid for lawn soil health .
  • High nitrogen content for a thicker lawn.
  • 16-4-8 N-P-K greens quickly in about 7 days.
  • 100% natural liquid fertilizer.
BEST GRANULAR
LESCO 50 lb. St. Augustine Grass Weed and Feed with Penoxsulam
Lesco Professional
  • Feeds for deep greening in just 3 days .
  • 2-in-1 formula feeds your St. Augustine adequately.
  • 16-4-8 N-P-K high nitrogen great for St. Augustine lawns
  • Other N-P-K ratios are available.

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Read on for my comprehensive reviews on the best fertilizers for St. Augustine grass to make an informed decision on which one is right for your lawn.

yard mastery starter fertilizer review

If you have just put down fresh St. Augustine sod, I would highly recommend looking at the Starter Fertilizer from Yard Mastery as this is the easiest way to put down the nutrients your new sod needs to build that strong root base.

Affiliate Disclaimer: As an Amazon Associate and participant in various other affiliate programs, I earn a small commission at no extra cost to you from qualifying purchases.


Best Fertilizers for St. Augustine Grass

Here’s the N-P-K nutrient analysis and comparison of the fertilizers:

There are numerous fertilizers in the market that are specifically made for St. Augustine grass. To find the best fertilizer for St. Augustine grass, look for high amounts of nitrogen, the ability not to burn your lawn, how fast you’ll see results, and other ingredients apart from NPK, etc.

Fertilizers with nitrogen, phosphorus, and potassium NPK ratio of 4-1-2 are generally a better choice for most areas. Here are the 7 best fertilizers for St. Augustine grass:


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1. Lesco Professional St. Augustine Weed & Feed Fertilizer 17-0-7

Lesco Professional St. Augustine Weed & Feed Fertilizer 17-0-7

Lesco is one of the brands that produce fertilizer specifically for St. Augustine grass. Lesco’s 17-0-7 weed and feed fertilizer is a pro-grade product that will provide not only the required amounts of nitrogen but also other nutrients such as iron.

If you’re looking to grow a lush green southern lawn, Lesco’s fertilizer is a great pick for your lawn. The iron is a major lift for lawns that are prone to brown patches.

The best time to apply this fertilizer is at the onset of spring. This will jump-start the growth and greening of your St. Augustine lawn, which is very important for outgrowing and choking out lawn weeds.

LESCO 50 lb. St. Augustine Grass Weed and Feed with Penoxsulam
35 Reviews
LESCO 50 lb. St. Augustine Grass Weed and Feed with Penoxsulam
  • Lesco Professional, 50 LB, 13,00 SQFT, 17-0-17 St Augustine Turf Fertilizer
  • 30% Poly Coated Sulfur Coated Urea, Specially For St. Augustine Grass
  • Should Be Applied When Turf Is Wet, Allow To Dry & Total Results In 2 Weeks, Safe For Floratam Variety, Slow Release Providing Up To 8 Weeks Of Feeding

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2. Simple Lawn Solutions Extreme Grass Growth Lawn Booster

Simple Lawn Solutions Extreme Grass Growth Lawn Booster
  • Highly advanced humic and fulvic acids for faster growth
  • Great nitrogen content for a greener lawn
  • 100% natural – it won’t harm kids or pets after spraying.
  • Noticeable lush green grass from 10 days.

Most of us want to ensure our St. Augustine grass spreads faster and grows into a thick lawn. This natural liquid lawn fertilizer is great if you’re establishing a St. Augustine grass lawn.

Apart from using it on St. Augustine lawns, you can also apply it on bermudagrass, zoysia, centipede, and palmetto lawns with great results within a window of 14 days.

Deal
Extreme Grass Growth Lawn Booster- Liquid Spray Concentrated...
3,272 Reviews
Extreme Grass Growth Lawn Booster- Liquid Spray Concentrated...
  • Increase Vertical & Lateral Growth: Advanced Humic Acid Formula, Also Great for New Sod/Seeding
  • Nitrogen & Phosphorus Fertilizer: Commercial Lawn Growth Boosting Formula in a Ready-To-Use Hose End Sprayer
  • Use For Nutrient Deficiency, New Lawns and Lawn Repair: Concentrated Nutrients formulated to boost the growth of your lawn

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3. Milorganite 0636 Organic Nitrogen Fertilizer

No products found.
  • Unlike most other slow-release fertilizers, you’ll start seeing results after about two weeks of application.
  • It contains iron that helps grow a lush green, thick St. Augustine grass.
  • Being a slow-release Nitrogen fertilizer, it won’t burn your lawn.

The reason why Milogranite organic nitrogen fertilizer is great for St. Augustine lawns is its slow-release capabilities. If you’ve tried another lawn feed before and ended up burning your lawn, I would recommend this particular product as long as you use it according to the instructions on the product label.

Milorganite fertilizer application | St.augustine grass cut at 4"| Granular insecticide application

No products found.


4. Scotts Turf Builder Lawn Food

Scotts Turf Builder Lawn Food
  • 32-0-4 NPK feeds St. Augustine for deeper roots faster.
  • Contains 2% iron for quick greening.
  • Will thicken your lawn fast.
  • Helps control weeds by thickening the lawn to choke out weeds.
  • Can be used on sod as well as seeded lawns.
Scotts Turf Builder Southern Lawn Fertilizer for Southern Grass,...
3,529 Reviews
Scotts Turf Builder Southern Lawn Fertilizer for Southern Grass,...
  • Scotts Turf Builder Southern Lawn Food is a fertilizer specially formulated for Southern lawns
  • The included Scotts All-in-One Particles build strong, deep grass roots to protect against heat and drought
  • Apply this grass fertilizer to a wet or dry lawn during the growing season

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BEST LIQUID FERTILIZER FOR ST. AUGUSTINE GRASS

5. Pennington’s Weed and Feed

Pennington's Weed and Feed
  • It combines both slow-release nitrogen and quick-acting nitrogen for the thick, green lawn result.
  • It provides extended feeding that lasts up to 3 months.
  • It contains iron – perfect for that lush dark green lawn.
  • It also kills over 200 weeds such as clover, dandelions, plantain, henbit, dollarweed, and chickweed.

If you desire ultra-green St. Augustine grass, one of the top-rated fertilizers in this space is Pennington’s southern Weed & Feed formula. It is a 34-0-4 fertilizer, and as such contains high amounts of nitrogen.

One of the things I like about it is that you can use it as a lawn broadleaf weed killer. It kills over 200 types of weeds.

The downside with this lawn St. Augustine turfgrass fertilizer is that you may need to put it down after 30 days if your lawn is heavily infested with weeds. Poor moisture conditions may also affect the results of greening.

Note that this fertilizer may not be the best for floral St. Augustine grass.

Pennington 100536600 UltraGreen Weed & Feed Lawn Fertilizer, 12.5...
1,063 Reviews
Pennington 100536600 UltraGreen Weed & Feed Lawn Fertilizer, 12.5...
  • Fertilizer and kills over 250 broadleaf weeds, including dandelion, henbit, dollar weed, White clover, plantain and chickweed
  • Treats northern and southern grasses
  • Not for floral St. Augustine

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6. Dr. Earth Organic Super Natural Lawn Fertilizer

Dr. Earth Organic Super Natural Lawn Fertilizer

This one comes either as a liquid fertilizer or in granular form. The nutrient ratio is 9-0-5, with a slow-release option that qualifies it as one of the best fertilizers for St. Augustine grass.

Dr. Earth Super Natural Lawn Fertilizer is 100% natural and all organic. Apart from being safe for your yard and lawn (if you have pets, kids, etc.), it is a slow-release formula that will feed your lawn over a long period with the right amounts of nitrogen without the side effect of burning it.

Dr. Earth 100 Life All Purpose Fertilizer, 12 lbs
50 Reviews
Dr. Earth 100 Life All Purpose Fertilizer, 12 lbs
  • 100% Organic and Natural
  • Contains no GMO's
  • Rich in humic acid

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7. Scotts EZ Patch Lawn Repair Fertilizer

Scotts EZ Patch Lawn Repair Fertilizer

If you have an actively growing lawn but can spot some bare patches here and there, Scotts EZ Patch Lawn Repair For St. Augustine Lawns is a great fertilizer you could use to fix the problem and feed your lawn.

It has a ready-to-use mulch and fertilizer for lawn repair specifically meant for St. Augustine grass lawns. The times I’ve used it, I saw results 6 times faster than most other lawn repair solutions out there.

Here’s a great video showing how to use this patch to repair lawn and its benefits.

How to repair St. Augustine Grass with Scotts® EZ Patch

Our preference is usually a fertilizer that not only feeds the lawn but also kills weeds including broadleaf and grassy weeds such as crabgrass and dallisgrass.

Proper care in terms of applying the right amounts of fertilizer, correct mowing and pest and disease control can produce a lush green lawn.

Before settling down on the fertilizer to buy for your lawn, do some research to see if the product is professionally formulated for your lawn.

Deal
Scotts EZ Patch Lawn Repair For St. Augustine Lawns - 3.75 lb.,...
2,594 Reviews
Scotts EZ Patch Lawn Repair For St. Augustine Lawns - 3.75 lb.,...
  • Combination mulch and fertilizer repairs St. Augustinegrass 60% faster with results 15 days after application ( vs. untreated control, results may vary)
  • Mulch: Absorbs 6x its weight in water and expands to surround the seed in a moist protective layer
  • Fertilizer: Exclusive controlled release technology feeds to promote growth and establishment of St. Augustinegrass

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Best Nitrogen Fertilizers for St. Augustine Lawn

The secret to growing St. Augustine grass faster is feeding. An adequate supply of nitrogen is very important if you want a thick, dark green lawn. However, proper care and maintenance goes without saying.

If you’re shopping for a top-quality nitrogen fertilizer for St. Augustine lawns, I would recommend you look at 3 different aspects:

  • Fertilizers with high nitrogen content
  • Fertilizers that come with iron as a supplement
  • Fertilizers that are slow-release or combine slow and quick-release effects

The best picks for high-nitrogen fertilizers for St. Augustine grass include Milorganite 0636 Organic Nitrogen Fertilizer and the products listed below.

Milorganite is a slow-release nitrogen fertilizer guaranteed to contain at least 6% nitrogen, 85% of which is water-insoluble. This makes it last and feeds your lawn for longer.

I’ve tried a lot of brands and individual products for my lawn and clients’ lawns. Above is my list and reviews of the top-quality high-nitrogen fertilizers for growing a thick, dense St. Augustine lawn without burning it. The best fertilizers to feed your St. Augustine grass lawn need to contain high nitrogen.

Pro Tip: Avoid fertilizers that contain high amounts of phosphorus because they can cause zinc and iron deficiency in your lawn. Before you start your spring St. Augustine fertilizer schedule, ensure you perform a soil test to determine the nutrients that are required for healthy grass growth.

What Is the Best Fertilizer Ratio for St. Augustine Grass?

I highly recommend performing a soil test to determine the best fertilizer ratio for St. Augustine grass because your lawn may be lacking certain nutrients that are present in your neighbor’s lawn. Refer to this list of healthy nutrients for your lawn.

However, in the absence of a soil test, a complete fertilizer with a 3-1-2 ratio of nitrogen, phosphorus, and potassium is an ideal choice for St. Augustine grass.

This type of turfgrass is ideally dormant in the winter, but you should still water it periodically when the weather is dry, warm, and windy. Water about once a week or provide roughly an inch of water per week during the winter.

Slow-release vs. Quick Release Fertilizers

A slow-release fertilizer is insoluble while a quick-release product is soluble. If you apply a quick-release fertilizer on a St. Augustine lawn, you’ll notice results within two weeks of application.

However, slow-release fertilizers take a longer time to show results. You may wait for up to 10 weeks to see results with this type of fertilizer. However, there are a few benefits to this compared to a quick-action fertilizer.

  • Slow-release fertilizers rarely burn out the lawn even at high temperatures.
  • Slow-release nitrogen fertilizers are less labor-intensive because you have to apply again after 8 – 10 weeks.

The only downside I’ve come across about slow-release nitrogen fertilizers for St. Augustine grass is that they’re slightly more expensive. However, they produce a fast-growth effect on your lawn.

The reason why you should be choosing a top-rated fertilizer for St. Augustine grass is that the rapid growth you’ll get will help you overcome weeds and lots of lawn diseases that are common with poor nutrition.

For example, you’ll find 24-2-11 fertilizers like this one from Lesco, which is best for St. Augustine grass in Florida.

SeedRanch St. Augustine Lawn 24-2-11 Fertilizer - 50 Lbs.
70 Reviews
SeedRanch St. Augustine Lawn 24-2-11 Fertilizer - 50 Lbs.
  • Includes 6% Iron for Excellent Greening.
  • 12,000 Sq.ft Coverage
  • Provides nutrients for St Augustine Lawns

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Fertilizer for Floratam St. Augustine Grass

fertilizer for floritam grass

Floratam is one of the best varieties of St. Augustine grass grown in lawns due it its great resistance to cinch bugs and diseases. It grows fast, meaning it also goes heavy on feeding (fertilizer and water).

  • Within 24 hours, this variety of St. Augustine grass can grow up to 3/4 inch laterally.
  • You need to fertilize floratam about 6 times a year, starting spring through fall.
  • When new, apply a 19-5-9 fertilizer to your sod or newly grown grass seed two weeks after planting.
  • Water the lawn adequately, especially after applying fertilizer.
  • Repeat the St. Augustine fertilizer schedule every 6 weeks until 6 months old.

But what is the best fertilizer for Floratam St. Augustine grass? While all the fertilizers I’ve reviewed above are great for St. Augustine grass, you’ll also find the ones below very nutritious for the Floratam variety that goes heavy on feeding.

Here are the best fertilizers for Floratam St. Augustine grass:


Osmocote Pro 19-5-8 Minors, 8- 9 Month

This fertilizer is great for early applications. It helps with the development of roots due to the high amounts of phosphorus and potassium.

It is recommended for foliage and root development. The slow-release ability makes it a go-to option for feeding your grass adequately without burning out the young shoots.

Osmocote Pro 19-5-8 Minors, 8-9 Month
58 Reviews
Osmocote Pro 19-5-8 Minors, 8-9 Month
  • Full season fertilization
  • Economical package
  • Offers complete nutrition

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Scotts Turf Builder WinterGuard Fall Weed & Feed

We’ve already seen a weed and feed fertilizer for St. Augustine grass, but the Scotts WinterGuard is excellent because it goes beyond just killing weeds. It provides great feeding in readiness for spring growth.

You can apply it in winter to help your lawn stock up on food as it waits for the onset of the sun and growing season.

This fertilizer improves the lawn’s ability to absorb water and nutrients versus an unfed lawn.

Scotts Turf Builder WinterGuard Fall Weed & Feed3, Weed Killer...
7,299 Reviews
Scotts Turf Builder WinterGuard Fall Weed & Feed3, Weed Killer...
  • Scotts Turf Builder WinterGuard Fall Weed & Feed3 weed killer and lawn fertilizer controls listed weeds and feeds grass in the fall for a better lawn next spring
  • Fall weed and feed kills over 50 listed lawn weeds, including clover, dandelion, plantain, morningglory, chicory, evening primrose, and purslane
  • Apply weed control plus grass fertilizer to a wet lawn when weeds are actively growing and temperatures are consistently between 60°F and 90°F

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How much fertilizer does St. Augustine grass need?

Knowing the correct amount of fertilizer is extremely important here. If you apply too little, you’ll end up with a deficient lawn and not the usual well-fed lush dark green St. Augustine lawns are known for.

Too much fertilizer is also a no NO. It can easily create an environment for pests to grow and thrive in your lawn.

It’s recommended to use a fertilizer spreader so you can set the application rate that is ideal for the product you are putting down. Did you know that excessive use of fertilizers can cause fertilizer burn?

The basic rule of fertilizing is this:

  • Apply 1 pound of nitrogen per 1,000 square feet of St. Augustine grass lawn.

This may not always be a simple task to do since fertilizer bags have different nutrient analyses on their labels – usually percentages of nitrogen, phosphorus, and potassium.

To determine the amount of nitrogen you need for your lawn, divide the first number indicated on the label of the fertilizer by 100. This will give you the weight you need to apply over a 1000 sq. Ft area of your lawn to be within the recommended amount.

Applying too much nitrogen on your lawn will burn your turfgrass. Dry fertilizers usually act like salts, meaning they’ll dehydrate plant material and cause burned blades. Brown leaf blades are a major sign you applied too much nitrogen on your lawn.

How To Calculate Fertilizer Rates

How Do You Make Homemade Fertilizer for St Augustine Grass?

There are several homemade fertilizer recipes you can make and apply to St Augustine grass but they will probably not provide the right N-P-K ratio needed for your turf.

Even if you do have readymade St. Augustine grass fertilizer, you can make the grass greener by adding homemade compost and making a few other soil amendments.

Homemade compost is perhaps the best St. Augustine grass fertilizer alternative and can be easily made with kitchen and yard waste.

Your homemade compost bin can include grass clippings, coffee grounds, egg shells, leaf mold, and trimmings from fruits and vegetables.

Regarding soil amendments, some good options are untreated sawdust, aged horse manure, and aged wood.

Spread the homemade fertilizer (compost) evenly across your lawn every 30 to 60 days starting from early spring to late fall.

Don’t forget to water your St.Augustine lawn regularly, which is best done by setting your lawn sprinklers at the right time instead of hand watering. St. Augustine grass thrives in moist soil up to 6 inches deep so water consistently every 3 to 6 days.


FAQs

What Is the Best Summer Fertilizer for St. Augustine Grass?

When on the shopping trail for the best summer fertilizer for St. Augustine grass, you’ll be spoilt for choice given the many options to choose from.

But if were to give you 5 great choices, they would be Pennington UltraGreen Lawn Fertilize – best overall, and Milorganite 0636 Nitrogen Fertilizer – best eco-friendly option.

What Time of Year Do You Fertilize St. Augustine?

You should fertilize St.Agustine grass twice a year during the growing season – early May and early July. Begin fertilizing 3 weeks after the St.Augustine grass turns green and apply another dose 8 weeks after the first application.

How to Grow St Augustine Grass?

St. Augustine grass grows well in the warmth of spring and summer. Plant sod or plugs in full sun and at least 90 days before your area’s first estimated fall frost, which will give St. Augustine grass plenty of time to establish. Read my article on where to buy St. Augustine grass seed and my tips on how to make St. Augustine grass spread.


Final Thoughts

St. Augustine grass should be fertilized twice a year during the growing season and most importantly with the right fertilizer.

Before picking up a bag of fertilizer, perform a soil test to determine the nutrients lacking in your soil. You can either apply liquid or granular fertilizer for St. Augustine grass, both of which are easy to use with a spreader or backpack sprayer.

If weeds are becoming an issue, make sure to check out the best weed killer for St. Augustine Grass.


References:


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1 thought on “7 Best Fertilizer for St. Augustine Grass [High Nitrogen, Liquid + Granular]”

  1. We bought a house recently. The lawn St. Augustine gras is thin and there is dallis grass and some type of weed that is vine like with small fern like leaves that fold when you touch them. We need to know how to feed our lawn for the winter and when to do it. Also best product to kill weeds. Thank you

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