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.

Both 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 3 top fertilizers for St. Augustine grass.

BEST LIQUID
Simple Lawn Solutions Extreme Grass Growth Lawn Booster- Quality...
BEST ORGANIC
Milorganite 62036-MW Organic Milorganite Fertilizer, 32-Lb. -...
FAST ACTION SYNTHETIC
Scotts Turf Builder Lawn Food, 12.5 lb. - Lawn Fertilizer Feeds...
Simple Lawn Solutions Extreme Grass Growth Lawn Booster
Milorganite Organic Fertilizer
Scotts Green Max Lawn Food with Iron Supplement
  • 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.
  • High nitrogen content for faster growth.
  • Won't burn your lawn.
  • Faster greening of St. Augustine lawns.
  • Highly-rated organic fertilizer for lawns.
  • Feeds for deep greening in just 3 days .
  • 2-in-1 formula feeds your St. Augustine adequately.
  • 27-0-2 N-P-K high nitrogen for better lawns.
  • Low phosphorus version for Florida available.
BEST LIQUID
Simple Lawn Solutions Extreme Grass Growth Lawn Booster- Quality...
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 ORGANIC
Milorganite 62036-MW Organic Milorganite Fertilizer, 32-Lb. -...
Milorganite Organic Fertilizer
  • High nitrogen content for faster growth.
  • Won't burn your lawn.
  • Faster greening of St. Augustine lawns.
  • Highly-rated organic fertilizer for lawns.
FAST ACTION SYNTHETIC
Scotts Turf Builder Lawn Food, 12.5 lb. - Lawn Fertilizer Feeds...
Scotts Green Max Lawn Food with Iron Supplement
  • Feeds for deep greening in just 3 days .
  • 2-in-1 formula feeds your St. Augustine adequately.
  • 27-0-2 N-P-K high nitrogen for better lawns.
  • Low phosphorus version for Florida available.

St. Augustine grass grows fast, making it a great choice for building a thick turf. The recommended fertilizer program begins in the spring. You’ll need to apply 1 – 1.5 pounds of nitrogen per 1000 sq. ft every 8 to 10 weeks for the best results. But what is the best fertilizer for St. Augustine grass lawns?

Best Fertilizer 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, you look for high amounts of nitrogen, the ability not to burn your lawn, how fast you’ll see results, 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 5 best fertilizers for St. Augustine grass:

1. Simple Lawn Solutions Extreme Grass Growth Lawn Booster

Best liquid fertilizer for st augustine grass
  • 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.


2. Milorganite 0636 Organic Nitrogen Fertilizer

Best Fertilizer for St. Augustine Grass - Milorganite Organic Fertilizer
  • 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 nature. If you’ve tried another lawn feed before and ended up burning your lawn, I would recommend this particular product.

Milorganite update!!!

3. Scotts Turf Builder Lawn Food

Scotts-Turf-Builder-Lawn-Food - fertilizer to make st augustine grass thick
  • 32-0-4 NPK feeds St. Augustine for deeper roots faster.
  • Contains 2% iron for quick greening.
  • Will thicken your lawn really fast.
  • Helps control weeds by thickening the lawn to choke out weeds.
  • Can be used on sod as well as seeded lawns.

BEST LIQUID FERTILIZER FOR ST. AUGUSTINE GRASS

4. Pennington’s Weed and Feed

Pennington Weed and Feed Fertilizer for St. Augustine Grass-min
  • 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.

Now for the ultra-green St. Augustine grass, one of the top-rated fertilizers in this class is the Pennington’s southern Weed & Feed formula. It is a 34-0-4 fertilizer, and as you can already tell, it contains high amounts of nitrogen.

One of the things I really 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.

5. Lesco St. Augustine Lawn Fertilizer 24-2-11

Best fertilizer for st augustine grass - Lesco professional turf fertilizer

Lesco is one of the brands that produce fertilizer specifically for St. Augustine grass. Lesco’s 24-2-11 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 chocking out lawn weeds.

6. Dr. Earth Organic Super Natural Lawn Fertilizer

Top quality fertilizer for st augustine grass

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 a 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.

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 repair lawn and its benefit.

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 scouting to see if the product is professionally formulated for your lawn.

For example, you’ll find 26-2-11 fertilizers best for St. Augustine grass in Florida. This may not be the best solution for other places such as Houston Texas.

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 go 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 the best 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.

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 calendar, ensure you do a soil test to determine the nutrients that are required.

Slow-release vs. Quick Release Fertilizers

A slow-release fertilizer is insoluble while a quick release one 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 to know 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.

Fertilizer for Floratam St. Augustine 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 really 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 in 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

Osmocote Blend fertilizer for st augustine grass - best for Floratam

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.

Scotts Turf Builder WinterGuard Fall Weed & Feed

Scotts weed and feed for Floratam st augustine grass in winter

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.

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.

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

Sources:

Clemson Cooperative College of Agriculture Forestry and Life Sciences HGIC Extension: St. Augustinegrass Yearly Maintenance Program

The Texas A&M University System: Maintaining St. Augustine Grass Lawns

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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