Best Fertilizer for St Augustine Grass. St Augustine grass (Stenotaphrum secundatum) is a warm season, fast-growing, and widely-adopted grass. The grass can grow and adapt to numerous variety of soils and pH levels.
It comes in several different cultivars including Bitterblue, Classic, DeltaShade, Floralawn, Floratam, Palmetto, and Raleigh.
If the St Augustine grass lawn is properly maintained with the right fertilizer, mowing and watering, it will produce a dense and lush of medium to dark green/blue-green colour grass. It can look like a new lawn.
For fertilizer, there is a wide range of choices for soil with deficiencies. This application of the fertilizer is to avoid impacting the health of your lawn.
There are various forms of fertilizer such as granules, pre-mixed, and concentrates.
What is the best fertilizer for St Augustine grass?
So, what is the best fertilizer for St Augustine grass? When selecting a St. Augustine grass fertilizer, you do not want to make a mistake. You have to have a good purchasing decision.
For St Augustine grass, you have to keep in mind to consider slow-release Nitrogen that can offer a longer-lasting and slower feeding to your St Augustine grass. Besides that, it is considered safer for the environment and your lawns.
Fertilizers product is usually known by their formulation of NPK such as 6-6-6 or 12-4-8 NPK formulation. This fertilizer is called a complete fertilizer because the blend contains N, P and K. The numbers indicate the percentage of each of these nutrients.
For example, a 12-4-8 fertilizer mixture, contains 12% Total Nitrogen, 4% Available Phosphorus and 8% Soluble Potash. For one 100 pounds of 12-4-8 NPK fertilizer bag would contain 12 lbs of nitrogen total, 4 pounds of available phosphate, and 8 pounds of potash.
St Augustine grass is very efficient at absorbing nitrogen so it needs more frequent and higher rates of nitrogen. If you expect good growth and vibrant colour of grass, it can be achieved with a 70/30 ratio of Nitrogen and other nutrients.
A ratio of 3-1-2 NPK is probably the best formulation mix for St Augustine grass. But, there are fertilizer mixes like a 26-2-14, 26-2-11, 12-4-8, 15-0-15, and 10-5-10 fertilizer for St Augustine. It would depend on the result of a soil test. If the soil has little or no Phosphorous, a good amount of Phosphorus may be required for the lawn.
You as a grower usually expect dark green and fast-growing St Augustine grass. But it could mean an excess of Nitrogen leads to dark green colour, excessive growth, and thatch. The excess of Nitrogen could lead to the grass have to be mowed more frequently. Nitrogen could potentially leach into the groundwater.
Potassium plays a good role in root growth. But it is second to Nitrogen in a total amount of fertilization program and to achieve optimal growth.
List of best fertilizer for St Augustine grass
1. Urban Farm Fertilizers Liquid Lawn Fertilizer for St Augustine Grass
This fertilizer contains a balanced 13-1-2 NPK. It derived from Vitazyme®, Mycorrhizae, Earthworm Castings, Bat Guano, Sea Kelp, Humic Acid, Amino acids, and Hydroponic-grade minerals. A mixture formula of Iron, macronutrients, micronutrients, and Calcium that is handcrafted for quality control.
You can use this fertilizer product with the intention of quick green-up for your St Augustine grass. You can apply the fertilizer using hose-end and tow-behind tank sprayers. It is in liquid form so it is easy to absorb.
Use a measuring cup when mixing with the rate of 1 tablespoon per gallon or 1/2 ounce per gallon. With just 1 gallon, a one-time application of this fertilizer can treat at least 1 to 2 acres or 44,000 to 88,000 square feet or 5,000 square miles of St Augustine Grass lawn. Some testimonials indicated that 1 gallon can be stretch to 3 acres or 134,000 square feet with great results.
The manufacturer recommends applying this fertilizer product every 1 to 3 weeks for maximum results. To use on 5,000 square feet of St Augustine Grass lawn, you can apply this fertilizer at a minimum of 8 applications with just one gallon of concentrate.
If you apply 2 times per month, you can use this fertilizer for 4 months at its price. You will get even deeper St Augustine Grass lawn if you apply this fertilizer more often like 1 application per week.
This fertilizer product can be considered as a super fertilizer for high nitrogen loving plants including Lettuce, Rhubarb, Brussels Sprouts, ornamental leafy vegetables, non-flowering ornamentals, and trees.
This fertilizer can provide the best result when applied as a heavy synthesis of compounds with the help of radiant energy applications on turf or grass. Apply until the leaf blades are wet and dripping. Apply the fertilizer in the evening when the lawn is in shade.
Leaf spray applications are more effective and better results with regular feedings. If there is an irrigation system, dilute only by 50-75% because of the frequent watering.
2. Southern Ag Chelated Liquid Iron for St Augustine Grass
This fertilizer contains Iron – 5.0%, and Sulfur – 3.40%. St Augustine grass is high, with leaves turn to yellow when nitrogen is low. The other cause of the yellowing colour of leaves and smear colour leaves is Iron deficiency. Usually, high alkaline soil is the cause of Iron deficiency in St. Augustine grass lawns.
High alkaline in the soil means that the pH level of the soil is above 7. You have to purchase a soil test kit to determine the pH level of your soil. If your soil is above 7 or is alkaline, lower the pH level in several ways including applying iron, sphagnum peat, elemental sulfur, aluminium sulfate, acidifying nitrogen, and organic mulches.
This fertilizer would be a perfect choice when you know that your St. Augustine grass lawn has an Iron deficiency. It will provide the St Augustine grass lawn with enough and sufficient Iron to aid the lawn to turn yellow into rich green.
Other than correcting the Iron deficiency, it will also prevent your lawn from having a low level of Iron. The 3.40% sulfur will be needed to affect a change in soil pH.
Since the form of the fertilizer is liquid, it has to be mixed with water and applied with a sprayer. It is very easy and simple to apply. It can also be applied to other plants including flowers, shrubs, trees, and vegetables.
The product is available in 16 ounces or 1 pint or 0.125 gallons and 128 ounces or 1 gallon. A spray application use 1 tablespoon per Gallon. For soil drench application use 1 ounce per 100 square feet. Lawn application use 1 pint or 16 ounces per 1,000 square feet.
3. Scotts 21814 Turf Builder Starter Food for St Augustine Grass
This fertilizer contains a balanced 24-25-4 NPK. It is derived from Methyleneureas, Urea, Potassium Chloride, and Ammonium Phosphate. The combination is suitable to develop strong roots and blade in a quick time.
Compare to grass that is not being applied with this fertilizer, it tends to be 70% thicker, and 35% quicker grass. It is possible because the grass gets a better absorption of nutrients and water.
It is suitable for all types of grass including St Augustine grass and a good choice for a new lawn or for the mature lawn.
On new grass, water them at least two times a day when they are in the shade. You can do it in the morning and evening.
The plant has to be watered at least 3 to 4 times a day during summer months and after being mowed 1 to 2 times. Mow the grass when it reaches at least 3 inches tall.
A 3 pounds bag can cover 1,000 square feet of St Augustine grass lawn. If you have 15 pounds bag, the application can cover 5,000 square feet of lawn. While a 42-pound bag can cover 14,000 square feet.
This fertilizer product is in granule form that has to be using a spreader to apply properly. After the application, water them evenly to ensure it gets into the ground and reach the roots. It works immediately because it soaks into the ground very fast.
4. Simple Lawn Solution Advanced 16-4-8 Balanced NPK for St Augustine Grass
This fertilizer product is a fertilizer with 16-4-8 NPK formulation. It is derived from Urea, Potassium Hydroxide, Ammonium Nitrate, Seaweed, and Fish. It is a natural product and free of harsh chemicals that can cause stress on the St Augustine grass lawn.
The Seaweed contains trace elements like iron, magnesium and zinc oxide. This ingredients will support plant health, root development and will help fight fungi.
The fish as fertilizer improves soil health, increases soil fertility. Fish as fertilizers provide burn-free nitrogen, primary nutrients of phosphorus and potassium.
It also contains calcium. These balance of nutrients provide strong and steady grass growth, to withstand disease and pest issues.
The 16-4-8 formulation is the right recommended ratio of micronutrient for the St Augustine grass lawn. This formulation will provide green and growth, energy for root support, and also to give health and strength.
It is suitable also for any grass type including Bermuda grass, Zoysia grass, Buffalo grass, Centipede grass, Florida Palmetto, Bahia grass, Fescue grass, Ryegrass, and Kentucky Bluegrass.
You do not have to worry about anything because this fertilizer is manufactured in the United States of America, by a family business (Simple Lawn Solution) with 25 years of experience in the turf industry.
32-ounce size can cover up to 3,200 square feet of St Augustine grass lawn.
5. Simple Lawn Solution Ultimate 3-18-18 NPK – Lawn Food Natural Liquid Fertilizer for St Augustine Grass
This fertilizer product has a 3-18-18 NPK formulation. This formulation increases the mobility of Phosphates. This will end up as a highly responsive, and efficient NPK.
The high level of Potassium is to fix Potassium deficiency. The low level of Potassium will affect grass plants greatly.
Symptoms of Potassium deficiency are Chlorosis. It is an abnormal loss of green colouration of leaves of grass.
The colour turns to yellow which leads to defoliation and shedding. The Potassium stimulates growth and in low level could lead to slow growth or poor root or poor stem development.
The high level of Phosphorus is also to fix Phosphorus deficiency. The early sign of a Phosphorus deficiency is reduced vigour or slowed the growth of grass.
The grass may appear dark green and seem not growing as expected. The appearance may continue to darken over time to purple.
If not corrected, then portions of the grass stand will lose density. This could cause the undesirable weed to grow, encroachment and soil erosion.
Both deficiencies can make your lawn can not withstand disease, fungus, and insect. This fertilizer product works well for St Augustine grass, Buffalo grass, Palmetto, Bluegrass, and other grass. Keep your lawn watered routinely to make sure nutrients are absorbed accordingly.
The fertilizer product feature increases growth responses, enhances root development, improves food mobility throughout the grass lawn, encourages sturdy and strength, aids to develop resistance to disease, is safe and natural, and free of harsh chemicals that can cause stress to the lawn.
6. Super Juice All in One Soluble Supplement Lawn Fertilizer for St Augustine Grass
This fertilizer product has a 14-2-4 NPK formulation. It is derived from Urea, Ammonium Phosphate, Monopotassium Phosphate, Magnesium Sulfate, Potassium Nitrate, Copper, Iron, Manganese, Zinc, Sea Kelp, and Humic Acid.
St Augustine grass needs fertilizer with a higher nitrogen content than Phosphorus and Potassium. Established grass lawns need about 4 pounds of nitrogen for every 1,000 square feet each year.
It is a concentrated soluble granule fertilizer for liquid application during the war and cool-season months. It is available in 13.6 pounds bag or 6.17 kilograms. With one bag of application, this can cover 43,560 square feet or 1 acre of lawn. At half rate of application (7-1-2 NPK) can cover up to 2 acres of turf.
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 was designed as a supplement during the fertilizer program. For a healthy lawn, it can be used as a primary fertilizer like golf courses.
As a supplement, this product can produce fast results during the spring months. These liquid supplemental fertilizers have been used for so long by golf courses.
7. The Andersons PGF Complete 16-4-8 Fertilizer with Humic DG for St Augustine Grass
This fertilizer product has a 16-4-8 NPK formulation. It is derived from Urea, Ammonium Phosphate, Monopotassium Phosphate, Magnesium Sulfate, Potassium Nitrate, Copper, Iron, Manganese, Zinc, Pulvic Acid, and Humic Acid (Humate). The formulation ratio is the number 1 most recommended ratio for lawns.
It comes in a form of granular fertilizer and available in 18 pounds or 8.16 kilograms. The high level of slow-release Nitrogen is good for encouraging healthy growth of lawns, trees, shrubs, and flowers.
The non-burning slow-release Nitrogen feeds the lawn for up to 10 weeks.
The 3% Iron provides a long-lasting green colour grass. While the Humate is proven to build organic matter in soils. These organic matters stimulate beneficial microbial activity and build living soil.
These granules absorb very fast and absorb completely when being watered well. If you purchase one bag, it can cover up to 5,000 square feet. It is a rather large area.
It is recommended to apply this fertilizer on every 7 to 8 weeks. This will produce the best results. You have to remember to be far away from drainage ditches or storm drains.
When to fertilize St Augustine Grass?
January to April
To start any fertilization of St. Augustine grass, you should know the result of the soil tests. You should purchase a soil test kit.
This would be the best time to test the soil. After you get the soil test result, you could determine that it is time to fertilize the grass.
Nitrogen should not be applied during this period. Fertilization program that is developed during the early spring, and it is followed by cold temperature, can result in damage to the lawn.
May to August
When the months reaches the end of April, you should prepare for further action. Add lime or sulfur after you get the soil test result. St Augustine grass grows best at a pH level of between 6 to 6.5.
If the soil test indicates a higher than 6.5 soil pH, you can add sulfur to lower the pH level. You can use 5 pounds of sulfur (pellet form) per 1,000 square feet of lawn.
At the start of May, you can now start applying 2 to 4 pounds of actual nitrogen. It is also recommended for per growing season, and per 1000 square feet of turf.
For sandy soil, a higher rate of Nitrogen can be applied. For clay soil, you should apply a lower rate.
It would be beneficial to apply a soluble Iron product, such as Chelated iron, in between fertilizer applications. Adding Iron will improve the green colour.
During the hot summer months, St Augustine grass should be fertilized at least three times.
Early Summer or in May
Nitrogen between ½ to 1 pound per 1,000 square feet should start being applied in early May. But the right rate of application would depend on the soil type. Before starting, you should do the soil test to know how many phosphorous is required.
Mid Summer or June to July
Start with a soil test and determine the required amount of Potassium and Phosphorus. For Nitrogen, apply ½ to 1 pound per 1,000 square feet containing high potassium fertilizer (15-0-15 NPK formulation).
The formulation is suitable for sandy soil. You can also add Phosphorous if it is recommended by a soil test.
Late Summer or August
During the late summer (before mid-August), fertilize the St Augustine grass lawn with ½ to 1 pound of Nitrogen per 1,000 square feet, (depending on soil type) with high Potassium fertilizer (15-0-15 NPK formulation).
You can also add Phosphorous if it is recommended by a soil test. Potassium is needed in this time of year to increase its resistance to disease and withstand the coming winter.
The amount of granular fertilizer needed to apply ½ pound of Nitrogen per 1,000 square feet, divide 50 by the first number on the fertilizer bag.
For 1 pound divide 100 by the first number on the fertilizer bag. The result is the number of pounds of product to apply to 1000 square feet of turf.
September to December
when it is September, Nitrogen should not be applied. Do soil tests and if recommended, apply lime or sulfur. If the soil test resulted in a low to medium levels of potassium, Potassium can be applied. The improvement of Potassium level can improve the resistance to the hardiness of winter months.
You can apply 1 pound of Potassium (K2O) per 1,000 square feet. Start the application 4 to 6 weeks before the first cold temperature. You can use 1.6 pounds of Potassium (0-0-60) or 2 pounds of potassium sulfate (0-0-50) per 1000 square feet.
How to fertilize St Augustine Grass?
Fertilizing a St Augustine grass lawn is very easy and simple. It will take less than 20 minutes. Here is how to do it.
Water your lawn. 2-3 days before you fertilize, give it a good watering. It is to make sure the soil is ready to accept fertilizer.
Use a spreader. Purchase a good spreader for your lawn. You can either choose a broadcast spreader and drop spreader.
Adjust spreader settings because each St Augustine grass fertilizer product has a unique spreader setting to get the right coverage. Read the instruction manual for selecting the proper setting for your spreader.
Apply grass fertilizer at the edge. First spread around the perimeter so you will not miss any of the edges. There is numerous broadcast spreader that can help you avoid getting run-off in garden beds, on sidewalks, or on driveways.
Fill in the middle of the lawn. Start walking back and forth all over the lawn in straight lines while slightly overlapping with each pass.
Properly handle the product after use. After finishing the fertilization, store any unused product to its original bag, cover it well and store it for future uses. Keep it in a cool, dry place away from people and pets.
How Often Should You Fertilize St Augustine Grass?
Fertilize warm-season grasses like St Augustine grass during active growth periods. Do not fertilize during the hot mid-summer months.
Fertilize St Augustine grass three phases. The first phase would be in early spring or when the grass starts to green. The second phase would be to fertilize in late spring. The third phase would be one time in late summer.
Noticing that your St Augustine grass lawn does not perform as expected, you have to fix this. When it starts to turn to yellow, you must act fast also.
Selecting a good fertilizer for St Augustine grass will absolutely normalize its life very fast. You can avoid any grass problems in time in the future.