St. Augustine grass is one of the most popular grass types due to its deep blue-green color and tolerance for heat and humidity. With proper soil maintenance, it makes your lawn the envy of the neighborhood.
Having tested 9 of the best-selling options on the market, I’ve compiled a list of the 9 best St. Augustine grass fertilizers to keep your St. Augustine grass lush and healthy.
9 Best Fertilizers for St. Augustine Grass
Best Balanced Option
Best Nitrogen Fertilizer
Best Liquid Lawn Food
Best Iron Supplement
Best Starter Fertilizer
Best for Lawn Repair
Best Professional Choice
Best Growth Booster
1. Pennington UltraGreen Starter Fertilizer
The best overall fertilizer for St Augustine grass is the Pennington UltraGreen Starter Fertilizer. It has an NPK ratio of 22-23-4 and 5% iron which helps lawns achieve a deep, dark green color.
This balanced ratio of nutrients helps the development of strong roots and lush grass blades. Its slow-release formula also means that your lawn will be continuously fed for up to 3 months with just one treatment.
- Comes in resealable packaging.
- Easy to use and spread the fertilizer.
- Comes with 5% iron for a lush green St Augustine lawn.
- 5000 sq. ft. coverage area
- Over-fertilizing can damage the lawn
2. Super Juice All-in-One Soluble Supplement Lawn Fertilizer
If you are looking for a balanced fertilizer for your lawn, you should look at this Doc’s Super Juice fertilizer. It has a 14-2-4 N-P-K ratio which ensures a good combination of Nitrogen, Phosphorus, and Potassium for your St Augustine lawn. If you want to use it at full strength, the ratio will be 14-2-4. You can also use it at half-strength, and the ratio will be 7-1-2.
This fertilizer comes in a dry mix for easy application. Just mix it with water and spray it on the lawn directly. This allows you to apply it evenly.
It’s filled with the goodness of micronutrients like copper, magnesium, manganese, sulfur, zinc, and 4% iron to improve the health of your lawn.
- The fertilizer is easy to mix and spread evenly.
- Contains micronutrients like magnesium, iron, and zinc.
- Can be used with full or half-strength according to your need.
- More expensive
3. Milorganite 0636 Organic Nitrogen Fertilizer
If you prefer a slow-release fertilizer for your St Augustine lawn, you should check out this Milorganite 0636 Organic Nitrogen Fertilizer with an NPK ratio of 6-4-0. It slowly releases vital nutrients while improving soil quality. While synthetic fertilizers target the roots of the grass, this fertilizer targets the soil to create longer-lasting results.
Plus, this slow-release fertilizer formula means that you only need to apply it every 10 weeks, and it will also reduce lawn mowing frequency as the grass grows slower.
Milorganite says: this eco-friendly Nitrogen fertilizer is derived from recycled nutrients produced by the water reclamation process. So, you don’t need to worry about your safety, your kids, and your pets.
- Covers a wide area; suitable for golf courses.
- It’s eco-friendly, so it’s safe for kids and pets.
- Being slow-release reduces the hassle of applying quite often.
- It’s not a highly-recommended choice for Bermuda grass.
- Doesn’t contain potassium
4. Simple Lawn Solutions Extreme Grass Growth Lawn Booster
If your primary concern is developing a solid root system, then Simple Lawn Solutions Extreme Grass Growth Lawn Booster is the solution. It has an NPK ratio of 6-18-0. The higher phosphorous levels ensure better root development. This is ideal for new lawns, whether you’re starting from seed or sod.
The liquid formula and spray nozzle make it super easy to apply. Just hook up to your hose and spray over your lawn.
- Easy to spray and use
- The coverage area of 3,200 square feet
- Enhances seed germination
- Humic acid boosts optimal nutrition intake
- No potassium
- There are better options if you have an established lawn
Next Read: Top Potato Fertilizers
5. Southern Ag Chelated Liquid Iron, 128oz -1 Gallon
If your primary objective is to make your lawn greener or to correct yellowing spots, then this liquid iron is for you.
If you notice yellow patches in your lawn, then your grass is probably lacking a vital nutrient, iron. This fertilizer treats any iron deficiency that your lawn may have. It contains 5% soluble iron and 3.5% chelated iron combined with sulfur. Apply this to your lawn to revive the lush green St. Augustine turf you always wanted.
- Makes your grass green
- Treats iron deficiency
- Can also be used on flowers, trees, and shrubs
- Only contains iron
6. Scotts 21814 Turf Builder Starter Food for New Grass
If you are starting your St. Augustine lawn from seedlings, then Scotts Turf Builder is your ideal turf builder. This fertilizer is specially formulated for new lawns and advertises 70% thicker grass with 35% quicker growth than unfed grass.
It has an NPK ratio of 24-25-4. These high levels of nitrogen and phosphorus ensure fast root and blade growth for your St. Augustine lawn.
- Thicker grass
- Faster growth
- Gives coverage for up to 14,000 square feet of lawn.
- Yields a strong upshot for seedlings.
- A specific type of spreader is needed, which may add to your hassle.
7. Scotts EZ Patch Lawn Repair For St. Augustine Lawns
If you’re having problems with specific patches on your St. Augustine lawn, try Scotts EZ Patch Lawn Repair!
It is an easy-to-use mulch and fertilizer in one solution. Add it to any problem lawn patch, and you’ll see an improvement within 15 days.
- Repairs grass 60% faster
- Creates a moist and protective shield
- 6x more water-absorbent
- Treat an area up to 85 square feet
- No extra mixing needed
- Error in the steps of using may lead to weed bait.
8. Leso SeedRanch St. Augustine Lawn 24-2-11 Fertilizer
SeedRanch St. Augustine Lawn Fertilizer is a professional-grade fertilizer that contains 6% iron and an NPK ratio of 24-2-11. This combination ensures fast-growing green grass for your lawn. It also has a large coverage area of 12,000 sq. ft.
- Grants extra greening to grasses.
- Coverage of 12,000 square feet.
- Easy to dissolve in water.
- Overfertilizing can burn the grass
9. Extreme Grass Growth Lawn Booster
If you are looking for an excellent liquid fertilizer for your St. Augustine turf, go for Extreme Grass Growth Lawn Booster!
It is a balanced fertilizer (16-4-8 NPK) with a blend of all the essential nutrients warm-season grass needs. It also treats common fungi and weeds.
You won’t need to find any extra tools to use it. Just fit the hose right over the bottle mouth and spray to spread all over your turf. That’s all!
- A balanced fluid lawn food.
- NPK 16-4-8.
- Ensures root vigor.
- Treats up to 3,200 square feet of yard.
- Not fit to use in winter.
Nutrition to Look for in St Augustine Grass Fertilizers
When researching fertilizers for your lawn, the information you come across can be overwhelming. Let us break down some of the most common terms you’ll encounter during your search.
What is NPK?
- Nitrogen (N) is a macronutrient that speeds up the growing process and makes grass greener.
- Phosphorus (P) is a macronutrient that promotes root growth and adds vigor.
- Potassium (K) is a macronutrient that strengthens the grass’ immunity and resistance to disease.
Also Read: Epsom Salt for Tomato Plants
What to Consider when Buying Fertilizer for St Augustine Grass?
Applying a good quality fertilizer will improve your St Augustine grass. But it’s quite a difficult thing to find a fertilizer that will benefit your St Augustine lawn with minimal effort. That’s why to get the best results from a fertilizer, here are some things you need to consider.
1. Organic or Synthetic Fertilizer
No matter which fertilizer you choose, your first concern should be ‘safety’ for you and the environment. When talking about safety, what can be a better option than organic fertilizers? Yes, we do agree that organic fertilizers are a safer option. However, safety is not the only thing we should be concerned about, we need to think about efficiency as well.
Synthetic fertilizers are more likely to show faster results compared to organic fertilizers, but they may also damage the natural balance of pH in the soil. Oh, one more thing, don’t forget the smell! Organic fertilizers have a more pungent smell than synthetic.
So, choose the one that you are comfortable with. And if you choose synthetic fertilizer, ensure you don’t use too much of it.
2. Quick-release or Slow-release
A quick-release fertilizer will give you results rapidly. If you want to see your lawn thrive quickly, this is what you need. However, you will remain busy throughout the grass growing season because you must apply the fertilizer multiple times.
A slow-release fertilizer will work slowly and keep providing nutrients to your grass for a long time. You may not notice changes quickly, but the results will last longer.
3. Types of Fertilizers
Granular: Granular fertilizers are generally slow-releasing. Its benefit is that it will provide nutrients for a comparatively longer time. Another great thing about this fertilizer is that you won’t need to fertilize frequently.
Liquid: If your goal is to achieve results quickly, you can opt for liquid fertilizers. The liquid usually gets absorbed quickly, so you can see results in as little as a week! But liquid fertilizers may require frequent application.
Water-soluble: Water-soluble fertilizers look like granular fertilizers, but they can dissolve in water and are fast-acting.
4. N-P-K Ratio
The term N-P-K ratio means the ratio of Nitrogen, Phosphorus, and Potassium in a fertilizer. All of these nutrients are important for the healthy growth of St. Augustine grass.
Key-Takeaway: choose a fertilizer that not only ensures a balanced N-P-K ratio but also provides enough Nitrogen so that your St. Augustine grass gets better growth. You can also get a soil test to help you understand which nutrients your soil lacks.