If you’re looking for the best fertilizer for St Augustine grass, you’re in luck.
Whether you’re looking for a liquid fertilizer to improve the soil quality of something granular to bring your grass back to life, we’re here to help you find the right fertilizer for your lawn.
We found a wide range of great choices to treat any soil deficiencies impacting the health of your lawn. Plus, there are various forms to choose from, including granules, pre-mixed, and concentrates.
Table of Contents
The 8 Best Fertilizers For St. Augustine Grass
There are a lot of reasons to use fertilizer and a variety of blends available. To make sure you get the best product for your St Augustine grass, have a look at the table below before moving onto our buying guide.
St. Augustine Grass Fertilizer Reviewed
1. Simple Lawn Solutions Lawn Food Natural Liquid Fertilizer
This fertilizer from Simple Lawn Solutions contains a key blend of nutrients as well as seaweed and fish. The complete formula is a perfect 16-4-8 blend that nourishes your lawn with natural and organic material instead of using harsh chemicals to get results.
The NPK ratio is ideal for keeping your grass lush and green while encouraging strong root growth. This blend will not work on lawns that are infested with weeds, fungus, disease, or insect infestations. It’s meant to help established lawns grow strong and green.
In addition to St. Augustine grass, this fertilizer also works with Bermuda, Florida Palmetto, Fescue, and Kentucky Bluegrass among others. The easy-to-apply formula has a host attachment right on the bottle so you don’t need any special tools for application.
Simple Lawn Solutions is a family-owned company started by former employees of the commercial lawn industry. They have 25 years of experience in the commercial lawn industry and you can trust this product to deliver.
2. Extreme Grass Growth Lawn Booster
Another great product from Simple Lawn Solutions is the extreme grass growth blend. Like their other products, this one is made and manufactured in the US by a company with more than 25 years of experience in the lawn care industry.
This fertilizer is great for St. Augustine grass as well as Buffalo, Palmetto, Zoysia, and Bluegrass. It comes in an easy-to-use bottle for quick and easy application. Just attach it to your garden hose and you’re ready to apply. It’s also kid and pet-friendly and safe to use anywhere.
The 6-19-0 NPK ratio delivers nitrogen and phosphorous to your lawn as well as humic and fulvic acid. It’s non-toxic and works well on newly seeded areas as well as established lawns. The formula is made using high-quality natural and organic food-grade ingredients that encourage both vertical and lateral growth.
3. Ultimate Lawn Food Natural Liquid Fertilizer
Simple Lawn Solution does it again with this ultimate 3-18-18 NPK fertilizer. This is an excellent choice for lawns showing signs of potassium and phosphorous deficiencies, including purple, red, or dark edges, poor root growth, yellowing, or low tolerance to extreme temperatures.
Low potassium or phosphorous can leave your lawn prone to disease and correcting the imbalance quickly is essential. This will enhance root development and improve the ability of the fertilizer to travel throughout your lawn.
This product works with St. Augustine grass as well as Buffalo, Palmetto, Bluegrass, and more. It makes the grass hardy and strong so that it’s better able to resist disease, fungus, and insect infestations.
Ultimate Lawn Food Natural Liquid Fertilizer is made using high-quality natural and organic ingredients. Everything is food-grade and it contains no harsh chemicals so it’s completely safe for children and pets. Application is easy, just attach the integrated nozzle to your garden hose and you’re all set.
4. Scotts Turf Builder Lawn Food
If you’re planting a new lawn, this fertilizer from Scotts is the perfect starter food to get your grass off on the right foot. It encourages quick growth and produces grass that’s up to 70% thicker and grows 35% faster than untreated grass.
The 24-25-4 NPK ratio is perfect for encouraging quick, strong root development and healthier blades. It works with all grass types, including St. Augustine.
Don’t think that this fertilizer is only for new growth. It’s also quite effective with established lawns as well as grass plugs and sod.
This fertilizer comes in granule form and requires a spreader for proper application. Afterward, water your lawn to make sure it gets into the ground to the roots. The small granular size soaks into the ground quickly to get to work fast.
5. Super Juice All in One Soluble Supplement Lawn Fertilizer
Next up is this all-in-one fertilizer called Super Juice. It really earns the name, too. What’s really unique about this product is that it’s a very fine dry mix that is meant to be mixed with water and applied with a sprayer. One bag is enough to cover an entire acre.
At full strength, this formula has a 14-2-4 NPK ratio but it can easily be mixed at half strength for a 7-1-2 blend. It comes in a foil-lined resealable bag so you can store the unused portion until the next application without worrying about any waste or contamination.
This fertilizer can be used as a primary treatment or as a supplement to what you currently use. The nutrients are absorbed quickly through the blades. Results may be visible in as little as one to four hours.
6. The Andersons Professional PGF Complete Fertilizer
Another great all-in-one formula is this granular fertilizer from the Andersons. This fine granular fertilizer has humates to increase soil quality and help regulate the nutritional requirements of your St. Augustine grass.
One of the nice things about this blend is the slow-release nitrogen which helps promote uniform growth for an extended period of time. Because these granules are so small compared to some of their competitors, they absorb quickly and completely when watered in.
The fertilizer has an NPK of 16-4-8 and includes two different types of nitrogen as well as humates and iron. While this is a new arrival in the residential market, it’s been used commercially for years.
One bag covers up to 5000 square feet so this is a great choice if you have a large yard. The manufacturer recommends reapplying every seven to eight weeks for the best results, being careful to avoid drainage ditches and storm drains.
7. Southern Ag Chelated Liquid Iron
This is a great choice if your St. Augustine grass is showing signs of an iron deficiency. It can help your lawn go from yellow and patchy to a deep, rich green. This is a concentrated liquid that is meant to be mixed with water and applied liberally with a sprayer.
Note that this product does not contain any nitrogen, phosphorus, or potassium. It is specifically for laws that need iron. Yellowing grass is the most common sign that there is an iron deficiency. It can correct current problems and prevent them from happening again in the future.
While this fertilizer is easy to apply with a garden hose and spray, it will stain masonry, paint, and concrete so be very careful when applying.
8. Urban Farm Fertilizers Liquid Lawn Fertilizer
Urban Farm Fertilizers handcrafts all of their formulas for tight quality control. It has a balanced 13-1-2 NPK, mycorrhizae, enzymes, and humic acid, a unique blend of both micro and macronutrients that provide 100% nutrition to your St. Augustine grass.
This one-gallon bottle treats up to 80,000 square feet or a 5,000 square-mile area at least eight times. Because it’s in liquid form, the fertilizer is easily absorbed and soaks down into the roots. Ingredients such as kelp, work casts, and bat guano increase the nutrients available in the root zone.
Urban Farm Fertilizers is a small, family-owned company dedicated to growing better plants. They started in hydroponics and have moved into developing precise mixes like this formula to improve the look of your lawn.
When to Fertilize St Augustine Grass?
To determine when to fertilize St. Augustine grass, it helps to first understand its natural growing pattern. This grass is considered a warm-season grass which means that it grows fast in the warm summer months and slows down in the winter.
St. Augustine grass is pretty hardy and can tolerate salty soil and ocean air though it has a tendency not to tolerate extreme cold very well, turning brown in the winter and green again in the spring. It also requires nitrogen-rich soil which is important to keep in mind when choosing a fertilizer.
For best results, fertilization should always be based on soil tests. During late summer and early spring from January to April is a good time to check the soil. At this point in the year, though, fertilizer with nitrogen should not be applied as it can cause significant damage.
From May to August as the summer heat moves in, test the soil again. Sulfer may need to be applied if the soil pH is too high. Fertilizer with nitrogen can be applied at this time following the package instruction.
Finally, as fall turns to winter from September to December, you should once again refrain from applying any fertilizer with nitrogen. Potassium heavy fertilizers are preferred for winter to keep the grass hardy through the winter and should be applied roughly four weeks before the first frost.
How Often Should You Fertilize St Augustine Grass?
During the summer growing season, a general guideline to follow is that St. Augustine grass should be fertilized three times.
The first should be late spring or early summer. Early May is generally a good time. Test the soil and make sure it has enough nitrogen and phosphorous and apply fertilizer as needed to correct the balance.
In the middle of summer sometime in June or July, test the soil again. You will likely have to apply additional nitrogen. High potassium fertilizers may be needed, too, depending on the test results.
At the end of summer before the middle of August, test the soil again. It will likely need nitrogen and potassium to help the grass stay strong and healthy as it goes dormant for the winter.
These are just general guidelines to follow. It’s very important to read the instructions on the fertilizer you’re using. Each will have slightly different directions for application depending on the formula and NPK ratio.
How to Fertilize St Augustine Grass?
How you apply the fertilizer very much depends on what type of fertilizer you’re using. While you should always follow the directions on the product you choose, here are some basic approaches to use when fertilizing your St Augustine grass.
Mixing Granules Prior to Application
Some of the products we chose come in the form of fine granules that are meant to be mixed with water and sprayed. The package of the fertilizer should have clear instructions as to how the granules should be mixed.
The great thing about this type of fertilizer is that you have control over how concentrated it is. You can dilute it if you want something less powerful. Another thing you can do is add extra water to give yourself more time to apply it to your whole yard.
Think about it like this; say you add a cup of granules to a gallon of water and a cup of granules to two gallons of water. Each contains the same amount of fertilizer. Having a larger volume to work with helps you make sure you have enough to cover everything.
Mixing Liquid Prior to Application
Again, it’s best to follow the instructions on the side of the container. Because you’re controlling how much water you’re adding to the concentrate, you can again choose to dilute the final product if necessary.
Using a Sprayer
Some fertilizers come pre-mixed in a large bottle with a built-in sprayer hose attachment which is one of the most convenient methods of application.
If you mix either granular or liquid fertilizer, you will need to get a sprayer of some sort. Hose sprayers are the easiest because, like the pre-mixed fertilizers, they attach right to your garden hose and are easy to use.
The other option is to invest in a sprayer. These come in many forms, usually either a tank that you carry around or one that you can wear like a backpack.
These sprayers are commonly operated using a pump and a wand and allow you to make your way around your yard spraying and even application of fertilizer to the area.
The best way to use a sprayer is to do the edges of your lawn first. Then, make your way back and forth moving from front to back or vice versa until your entire lawn is covered.
It’s important to mention that liquid fertilizer isn’t easy to apply. While hose sprayers may be very convenient, it’s difficult to make sure you’re getting an even application across your entire lawn.
Most granules are designed to be applied directly to your grass and not mixed with water and sprayed. Again, pay close attention to the instructions on the side of the container or bag.
The most effective way to apply granules is to use a broadcast spreader. It’s very difficult to apply granular fertilizer by hand. If you don’t have a broadcast spreader, most home improvement stores have them available for rent.
The first thing to do is to make sure the spreader is set correctly for the size of your lawn and the amount of fertilizer you’re applying. This calibrates the machine to release the granules evenly as you make your way around the yard.
Fill the spreader with the granules on a hard surface being sure to clean up any spills to avoid run-off later. Start at the edge of the lawn, moving at a steady, normal speed. Then, go back and forth from one side of the lawn to the other.
The best way to make sure you’re not missing any areas is to try to overlap with the path of the wheel left in the grass from the previous pass over the lawn.
After fertilizing, water the lawn thoroughly. This activates the granules in a way, carrying the nutrients into the soil and allowing the fertilizer to penetrate down to the root. It also makes sure that the granules won’t be washed away by heavy rain.
If your St Augustine grass isn’t growing as quickly as you like or is starting to turn yellow, it’s time to take action. Choosing a good fertilizer for St Augustine grass can help bring it back to life quickly and prevent problems in the future.
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