Gardening Tools

12 Best Fertilizer for St. Augustine Grass 2022

If you’ve chosen St. Augustine grass you’ve made a great selection. It is lush and a lovely blue-green color. It is strong; once established, it grows quickly. Weather-wise, your lawn tolerates heat and humidity, something others can’t do. Even with all of the above, your St. Augustine lawn needs fertilizing to keep it at its best. A lawn can’t be at its best however, if it hasn’t the strength to struggle through. Keep your lawn healthy, robust and able to deal with heat, cold, stress, disease, and everyday family use with fertilizer application.

How to Choose the Best Fertilizer

Fertilizer is one of the big-three things your lawn needs (the other two being water and mowing). Fertilizers contain nitrogen, its importance to plants is represented by its first and foremost appearance in the numbers shown on fertilizer packaging (as in 16-4-8 recommendation for St. Augustine grass.) While nitrogen is naturally in the air, plants can’t capture it. Without it, growth declines. Of course, your lawn benefits from other boosters, but NPK, (nitrogen, phosphorus and potassium) are key.

Do you want to enhance your soil as well as your lawn? The answer to that one is, why yes, you do!) The top of the ground impact is noticeable, but you can’t neglect the soil condition underneath. The soil deteriorates as the grass takes nutrients from it. Nutrients get imbalanced. You have to treat the whole package. Good soil saves watering, energy, mowing, expense and the environment.

The excellent products listed below keep all these issues in mind. What resonates with your lawn needs? What fits your budget?

st. augustine grass

Top 12 Best Fertilizers for St. Augustine Grass

Simple Lawn Solutions Food Natural Liquid Fertilizer4.7
The Andersons PGF Complete 16-4-8 Fertilizer with Humic DG 5,000 sq.ft4.8
Southern Ag Chelated Liquid Iron4.6
Super Juice All-In-One by The Andersons4.6
Espoma EOLB30 Organic Lawn Booster Fertilizer4.4
Urban Farm Liquid Fertilizer4.6
LawnStar Chelated Liquid Iron4.9
Organic Liquid Humic by GS Plant Foods4.9
Lesco Turf Fertilizer by Lesco4.4
Safer Brand Organic Lawn Care - Lawn Restore4.5
Scotts Natural Turf Builder Liquid4.4
Dr. Earth 751 Liquid Solution Pro Biotic 3-3-34.5

1. Simple Lawn Solutions Food Natural Liquid Fertilizer

This organic product contains key macronutrients, fish and seaweed that provide energy for root support. There are no harsh chemicals and this means your fertilized lawn is safe for children, other humans, pets, bees, birds and pollinators. The formula greens grass quickly, and continues to improve the root strength of each little blade of grass. The NPK is 16-4-8, recommended to keep St. Augustine grass healthy and beautiful. Many happy customers, many seeing grass standing tall, growing inches per day.


  • Happy customers like that the fertilizer works well on St. Augustine grass. The grass is greener, and looks good. For a lawn on the mend, rejuvenated grass fills bare spots
  • It is weather-friendly and reacts well with minimum rain, heat and humidity.
  • The product, rated a good value for the money, is everything you need to keep lawn from getting heat stressed.
  • Many liked its ease of use and application.


  • Some customers experienced applicator problems. The switch isn’t easy to turn on and off which meant the contents were used up quickly.
  • Expectations: some didn’t see major changes as quickly as they wished.

2. The Andersons PGF Complete 16-4-8 Fertilizer with Humic DG 5,000 sq.ft 

The 16-4-8 formula is high in iron and micronutrients. It has the added benefit that Humic DG provides. The latter is a natural soil conditioner that improves long-term soil pH. Humic material has proven especially beneficial in tropical, humid climates with higher soil temperatures. Nutrients are released slowly for better plant and soil absorption. The slow release is beneficial, and a few nice rains and it is even better.


  • It has great reviews from St. Augustine grass owners. Their lawns are now nice and thick.
  • It distributes beautifully.
  • All in One does as advertised.


  • Spreaders may need readjustments.
  • It is a little pricey per pound.

3. Southern Ag Chelated Liquid Iron

If your lawn looks stressed and seems to be struggling, it may be suffering from iron deficiency. The manufacturer, in business since the 1930s, specializes in fertilizers and they know all about the importance of replacing iron. Using chelated liquid iron helps your St. Augustine grass make the chlorophyll it needs for growth. Apply 1 tablespoon per gallon of water and watch it thrive.


  • Happy customers report that it works great as promised and it is easy to use. They felt the pricing is fair.
  • Several commented how well it worked for spot treatments.
  • Lawns greened-up in days, not weeks. In fact, the product greened everything.


  • The amount was smaller than anticipated, and the customer suggested more may be needed.
  • A few mentioned difficulty with the hose and sprayer, though they just switched to doing in manually.
  • The iron doesn’t smell good.
  • It stains concrete. Watch out!

4. Super Juice All-In-One by The Andersons

Doc’s Super Juice. All the nutrients in a dry mix, and an enrichment if your lawn needs “Intensive Care.” Your lawn gets what it thirsts for to thrive because it gets right to the soil. One bag treats an acre of lawn, so anything smaller means you could have several treatments. Dilute at half strength and get even more. “Doc” has a series of helpful videos too. The NPK: 14-2-4.


  • Happy customers say lawns noticeably looked really good; green and healthy. A few saw the difference quickly.
  • Many appreciated that the product is pet friendly.


  • Some found it hard to mix, and that it  clogs sprayers. They found that warm water and a screen mesh dissolves product quicker.
  • Price

5. Espoma EOLB30 Organic Lawn Booster Fertilizer

This organic lawn booster is made from feather meal, pasteurized poultry manure and gypsum, which are products certified organic crop producers use for concentrated nitrogen sources. It is environmentally friendly and safe for children and pets. Applied in the spring, the product discourages weeds, but use it anytime of year. 8-0-0 Formulation.


  • The product is easy to use, organic and safe, and that made customers happy.
  • Many noticed their grass perked up quickly. What looked pitiful “is coming back!”
  • Lots of feeling that the product transformed their lawn, with grass looking and feeling great.


  • The odor isn’t the greatest, but the complaining customer realized that it is a fertilizer.

6. Urban Farm Liquid Fertilizer

This product is naturally organic. For those who know about, or are sparked to learn, the fertilizer contains bat guanos and kelp in its many bioactive ingredients. While it may seem like a low NPK, 13-1-2,  it is powerful in natural ways. The product is super concentrated. It is not only good for your lawn but also for ornamentals and trees for a nice triple punch.


  • It works better than described with grass seeming to grow overnight.
  • It is a go-to product for the summer months. The grass looks good even at 100 F.
  • No problem with the price, and many commented that it is super affordable.
  • Lawn recovered with this product, add a little chelated iron – it is like magic.


  • Need to adjust the recipe before seeing results (one customer had success tripling it.)
  • Directions need to be clearer to understand the concentration.

7. LawnStar Chelated Liquid Iron

Iron deficiency results in color distortion and root damage in your lawn. Grass gets tired and when tired, it goes dormant. An iron treatment wakes it up as soon as the nutrients seep to the plant base. Root development begins again. Soil that became highly alkaline is revitalized. LawnStar has CLI’s sugar chelator, something not found in many liquid irons. No NPK. EDTA free, better and safer. It is an iron treatment.


  • Happy customers commented on how their lawn regained grass color almost overnight. It is also good for summer greening.
  • A soil test determined that the product changed the soil composition in 24 hours. Great for alkaline soil. Many discovered new growth in just a few days, even with shrubs and trees.
  • It does what the label says.


  • The product may stain concrete.
  • The directions aren’t clear about how much water to mix with it. Read carefully to avoid leading to wrong doses.
  • A few experienced a challenge with shipping, receiving leaky containers.

8. Organic Liquid Humic by GS Plant Foods

Humic supplies key minerals that plants need for natural growth, when grass needs it, step back and watch the quick improvements. You could literally watch your lawn come back to life. Organic Liquid Humic also benefits flowers, trees and even vegetables, so it is very all-purpose. Be sure to treat your lawn with an application in the fall for next spring, to build soil strength for the next growing season.


  • A happy customer said: “Awesome plant growth in a bottle!” It provided quick results in the health of plants. Magical results on flowers and vegetables too.
  • Customers experienced positive results, even on bare grass areas
  • The best fertilizer one pleased gardener ever used.


  • For a few, the container is poorly designed and the directions aren’t clear.

9. Lesco Turf Fertilizer by Lesco

The turf fertilizer keeps St. Augustine grass the healthy blue-green color people love. The product is designed to control the release of nitrogen. The controlled release is beneficial because maximizes the potential that the roots absorb it. Healthy plants from the root up reduce water usage and decrease mowing. Plants have the ability to deal with climate stresses.


  • The best for St. Augustine grass.
  • 5-Star and no problems.


  • Pricing variations

10. Safer Brand Organic Lawn Care – Lawn Restore

This product is a new and improved version of Ringer Lawn Restore. The formula is designed to help plants endure heat, extreme cold, drought stresses, and other environmental pressures. It is effective all year long with a slow, steady release. It works especially well in sub-tropical and tropical climates. Apply mid-spring, in late fall and in the fall. It is safe for children and pets. A 9-0-2 NPK. Depending on soil test, you may need to augment.


  • A great value and product is better than expected, pleasing many customers.
  • Several commented that their lawn was evenly green and required less watering
  • The lawn is lush, never burned – it stayed green all summer. It may take longer to green-up but once it does it stays green longer.
  • It is organic, pleasing dog owners.


  • Old customers did not like the ‘new’ product formula.
  • A few complained about the odor.
  • It is expensive

11. Scotts Natural Turf Builder Liquid

This is an improved product, usable in any season when your lawn is actively growing. It enhances the special St. Augustine color. Applications in early spring, late spring, early fall and late fall help your lawn deal with stresses like heat, drought, weeds and family activity. It is easy to use, just hook up to your hose.


  • A great product. Happy customers liked that their grass is now greener than ever.
  • It does the job, and the results are good
  • It is a food and a growth booster, something a happy customer highly recommends to everyone.


  • The sprayer is the worst! Pour it into another sprayer and you are good to go.
  • Expensive

12. Dr. Earth 751 Liquid Solution Pro Biotic 3-3-3

This is an all-purpose solution that stimulates root growth. It is also natural and organic, with an oceangoing fish, kelp and seaweed formula. It also contains rock phosphates (check local laws for phosphorous runoff). Sea formulas encourage healthy growth, proven forever as gardeners know. This is an excellent product to apply when your grass wakes in the spring from a long winter nap. After that, apply every 2-3 weeks through the growing season.


  • It smells terrible, but it does the job
  • Rates a 5-Star
  • Amazing results


  • Smells terrible; only use it outdoors
  • The picture makes it look like a huge amount, but it is only 16 oz.


When do I start fertilizer treatment?

Spring is the best time to begin and fall follows in a close second. Otherwise, nature brings heavy rains, heat and humidity. Rains may stop. Mid-summer is iffy. Let’s skip that and look at the best seasons (in other words; go easy in the summer.). Soil temperature has to be at least 65 degrees for either pre-treating for the spring or fall. One prepares you for the summer and one for the winter. You might do revitalization in the summer, with caution. Don’t think if you missed the spring, you’ll double the dose. Wait.

How Often?

Generally, the recommendations are for every one to three weeks. Fertilizing and treating grass with added nutrients make soil more porous, with benefits that you won’t need to water as much. Water too much, btw, and excess water leeches the fertilizer from the soil, takes it past the root system and your grass won’t get what it needs the most.


Please follow the manufacturer’s recommendations. Some suggest zero chance of rain for a period of 24 hours. Allow 24 hours before you water again. For your lawn’s sake, apply early in the morning (and that means “early.”)  Never when it is hot or midday, certainly not during a drought or heatwave. Leave the lawn alone!

I’ve read a lot about soil tests, should I have one done first?

Professional recommendations suggest a soil test at least once every 2-3 years. This ensures you are adding the right nutrient blend.  It really is all about the soil and returning to it, what it loses in organic matter. Soil test kit at Amazon, plug it in and read. Gives the fertility of soil, pH level and, nutrient deficiencies.

My yard has shady spots, do I use the same amount of fertilizer there?

Good question! The best answer is no.  Cut the mixture in half, observe, and if needed apply again just to the areas.


St. Augustine grass is hearty, in fact it revives quickly, but you ease the potential for emergency treatment if you fertilize and let your lawn develop a strong root system. The deeper the root system, the stronger your plant is.

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