St. Augustinegrass is a popular southern turfgrass due to its density and durability. Although low-maintenance, it needs a nutritious diet to thrive, and it can be sensitive to some fertilizers. That’s why we scoured Home Depot, Lowe’s, Amazon, and Walmart to find the best fertilizers for St. Augustinegrass. We review each one and include a buyer’s guide to help you maintain a lush and vibrant St. Augustine lawn.
Top picks
Top 6 lawn fertilizers for St. Augustinegrass – Reviews
1. The Andersons PGF Complete 16-4-8 Fertilizer
If you want a lush deep green lawn, try The Andersons PGF Complete 16-4-8 Fertilizer. It’s well-balanced with the nutrients St. Augustine needs to fight against weeds, pests, and diseases. The formula promotes healthy root growth and increases tolerance to heat, cold, and drought. It feeds your lawn everything it needs to succeed, with green-up in as little as a week.
Specifications
- Coverage area: 10,000 sq. ft.
- Effective period: 8 weeks
- Fertilizer type: Granular, slow-release, synthetic
- N-P-K: 16-4-8
- Package size: 40 lb.
Pros and cons
| What we liked | What we didn’t like |
| ✓ Improves cold-tolerance ✓ Improves immune system ✓ Well-balanced diet ✓ Very fine granules distribute well | ✗ Sometimes green-up can take up to a month ✗ Some states ban phosphorus fertilizers |
Where to buy:
2. Espoma Organic Lawn Food
Nitrogen encourages grass growth and gives lawns a rich green color, so successful St. Augustinegrass needs a lot of it. Espoma Organic Lawn Food is a certified organic source of nitrogen and bio-tone microbes. Bio-tone microbes are tiny organisms that improve the soil, so the grass grows an extensive root system. The long-lasting formula won’t burn your lawn and is safe for children and pets.
Specifications
- Coverage area: 2,500 sq. ft.
- Effective period: 12 weeks
- Fertilizer type: Granular, slow-release, organic
- N-P-K: 9-0-0
- Package size: 14 lb.
Pros and cons
| What we liked | What we didn’t like |
| ✓ Organic ✓ Great for spring feeding ✓ Improves soil conditions ✓ Long-lasting ✓ Safe for children and pets | ✗ No potassium ✗ No phosphorus |
Where to buy:
3. Safer Brand Lawn Restore Natural Fertilizer
Another organic fertilizer excellent for St. Augustinegrass is Safer Brand Lawn Restore Natural Fertilizer. It nourishes your grass to grow thick and vibrant without polluting the soil with synthetic chemicals. Instead, it contains a healthy mix of ingredients that invigorate the soil for long-term growth. It’s safe for children and pets and won’t burn your lawn.
Specifications
- Coverage area: 5,000 sq. ft.
- Effective period: 8 weeks
- Fertilizer type: Granular, slow-release, organic
- N-P-K: 9-0-2
- Package size: 20 lb.
Pros and cons
| What we liked | What we didn’t like |
| ✓ Organic ✓ Safe for children and pets ✓ Improves soil conditions ✓ Improves cold-tolerance | ✗ No phosphorus |
Where to buy:
4. Simple Lawn Solutions Advanced 16-4-8
Simple Lawn Solutions Advanced 16-4-8 Lawn Food provides all the macronutrients St. Augustine turfgrass needs to thrive. The high-quality solution contains feed-grade ingredients perfectly balanced to strengthen your grass and improve its appearance. As a result, lawns develop healthy roots and a higher tolerance to irritants such as cold weather and diseases.
Specifications
- Coverage area: 3,200 sq. ft.
- Effective period: 2 weeks
- Fertilizer type: Liquid, contains some organic ingredients but is not certified organic
- N-P-K: 16-4-8
- Package size: 32 oz.
Pros and cons
| What we liked | What we didn’t like |
| ✓ Improves cold-tolerance ✓ Improves immune system ✓ Well-balanced diet ✓ Made in USA | ✗ Some states ban phosphorus fertilizers |
Where to buy:
5. Scotts Turf Builder Southern Lawn Food
Many southern states face fierce heat waves and extended dry spells. Though St. Augustinegrass tolerates heat and drought moderately well, it could still use some help in especially hot, dry climates, such as in the Southwest.
That’s where Scotts Southern Lawn Food comes in, with powerful protection against heat and drought damage. It also strengthens your grass for winter survival and contains a lot of nitrogen to promote dense growth and vibrant color.
Specifications
- Coverage area: 5,000 sq. ft.
- Effective period: 6 – 8 weeks
- Fertilizer type: Granular, slow-release, synthetic
- N-P-K: 32-0-10
- Package size: 14.06 lb.
Pros and cons
| What we liked | What we didn’t like |
| ✓ Strengths weather tolerance ✓ Promotes dense growth ✓ Improves immune system ✓ Formulated for southern climates | ✗ No phosphorus ✗ If you apply too much, it can easily burn grass |
Where to buy:
6. Down to Earth Bio-Turf 8-3-5 Fertilizer
Down to Earth Bio-Turf 8-3-5 Fertilizer has all the nourishment St. Augustine needs to grow lush and strong. It’s OMRI certified for organic use and can also feed nitrogen-hungry crops like corn and tomatoes. Its formula strengthens turfgrass’s tolerance to heat, cold, and drought and encourages healthy root growth. Its natural ingredients include feather, meat, and bone meal.
Specifications
- Coverage area: 500 – 1,000 sq. ft.
- Effective period: 8 weeks
- Fertilizer type: Granular, slow-release, organic
- N-P-K: 8-3-5
- Package size: 6 lb
Pros and cons
| What we liked | What we didn’t like |
| ✓ Organic ✓ Improves soil ✓ Strengths weather tolerance ✓ Improves immune system | ✗ Not much coverage per package ✗ Some states ban phosphorus fertilizers |
Where to buy:
Buyer’s guide to lawn fertilizers for St. Augustinegrass
To select the best fertilizer for St. Augustinegrass, please consider the following.
Nutrients
The best way to identify your lawn’s nutritional needs is to test the soil. A soil test will essentially “diagnose” your soil and let you know if your lawn has any specific nutrient deficiencies that need treating.
However, here we outline general guidelines for St. Augustinegrass fertilizer.
NPK
The three main nutrients lawns need are NPK:
- Nitrogen (N) gives St. Augustinegrass its beautiful deep green color. During spring and summer, each application should contain 0.5 to 1 pound of nitrogen per 1,000 square feet of lawn or 1.5 pounds of slow-release nitrogen per 1,000 square feet of lawn.
- Phosphorus (P) encourages healthy root development, so it’s crucial when establishing new grass. Lawns need very little once established, so there is often enough in the soil. Runoff water with too much phosphate can harm sea life, so some states ban phosphorus fertilizers.
- Potassium (K) strengthens your grass’s immunity and makes it more tolerant against the elements, as well as pests and lawn diseases.
Typically recommended NPK ratios for St. Augustine lawns are:
- 4-1-2
- 3-1-2
- 3-0-0
How much of each nutrient does my fertilizer contain? Each fertilizer package states the N-P-K and package weight. If you buy a 20-pound bag of fertilizer and it has an N-P-K of 30-2-10, here’s how you would calculate the amount of each nutrient contained therein:
- Nitrogen (N): 30% of the fertilizer’s weight is nitrogen, so 0.3 x 20 = 6 pounds of N
- Phosphorus (P): 2% of the fertilizer’s weight is from phosphorous, so 0.02 x 20 =0 .4 pounds of P
- Potassium (K): 10% of the fertilizer’s weight is potassium, so 0.1 x 20 =2 pounds of K
Micronutrients
In addition to NPK, a soil test may reveal your lawn needs additional nutrients, such as iron or magnesium. St. Augustine needs these micronutrients in small doses, so always test the soil before treating micronutrient deficiencies.
Time of year
Fertilize St. Augustinegrass every 8 – 10 weeks during the spring and summer. Most homeowners stop fertilizing by mid-September, and you shouldn’t fertilize St. Augustine in the winter.
If you fertilize in the fall, never apply more than half a pound of nitrogen per 1,000 square feet of lawn. You also shouldn’t exceed 5 pounds of nitrogen per 1,000 square feet in a calendar year.
Type of fertilizer
There are various types of fertilizers:
- Slow-release vs. quick-release fertilizer: Slow-release fertilizer (also called controlled release) slowly breaks down into the soil, so you don’t have to apply it as often. Quick-release fertilizers need more applications and are more likely to cause fertilizer burn.
- Organic vs. synthetic fertilizer: Organic fertilizers take longer to work but yield better long-run results. However, synthetic fertilizers are often cheaper unless you make your own organic fertilizer.
- Liquid vs. granular fertilizer: Most granular fertilizers are cheaper than liquid fertilizers, and granules tend to be slow-release. Granular fertilizer application is done using a spreader, and liquids are applied using a sprayer or watering can. Read Liquid vs. Granular Fertilizer to learn more.
- Weed and feed: Weed and feed contains fertilizer and herbicide, so it feeds the grass and treats common lawn weeds. Herbicides that treat grassy weeds, such as crabgrass, may also kill St. Augustine. Before purchasing weed and feed, check the label to see if it’s marked safe for your grass type.
Cost of fertilization
Depending on lawn size and fertilizer type, DIY lawn fertilization typically costs $40 to $320. In contrast, pros usually charge $120 to $480 per fertilization service.
FAQ about lawn fertilizers for St. Augustinegrass
The best organic fertilizers for St. Augustine are:
• Espoma Organic Lawn Booster
• Safer Brand Lawn Restore Natural Fertilizer
• Down to Earth Bio-Turf 8-3-5 Fertilizer
A soil pH level between 6 and 7.5 encourages healthy grass growth for St. Augustine lawns.
The best post-emergent herbicide for St. Augustinegrass is Southern Ag 2,4-D Amine. The best pre-emergent herbicides include Quali-Pro Prodiamine 65 WDG and Dimension 2EW.
The best lawn fertilizer for your property depends on your grass type, so we also found the best lawn fertilizers for the following warm-season grasses:
• Bermudagrass: The best fertilizers for Bermuda include Simple Lawn Solutions Advanced 16-4-8 and Milorganite Slow-Release Nitrogen Fertilizer, but if you’re establishing a new lawn, try Pennington Smart Seed Bermudagrass Seed and Fertilizer Mix.
• Centipedegrass: The best fertilizers for centipede include Simple Lawn Solutions 15-0-15 Liquid Fertilizer and Ferti-lome Centipede Lawn Fertilizer 15-0-15.
• Zoysiagrass: The best fertilizers for Zoysia include Simple Lawn Solutions Advanced 16-4-8 and The Andersons Professional PGF Complete 16-4-8.
In Central and North Florida, you should start fertilizing St. Augustinegrass lawns in spring when the grass greens. It will need 2 to 6 applications, and fertilization should stop in the fall. Don’t fertilize when there is a risk of frost.
South Florida’s tropical climate creates a year-round growing season for St. Augustinegrass, so it needs fertilization throughout the entire year.
Large patch, also called brown patch, is often the reason why St. Augustine gets brown patches. It’s a fungal disease that causes yellow, tan, red, and orange circular patches at least 1 foot in diameter. There are organic and chemical treatments for brown patch.
When to call a lawn care pro
If you want your St. Augustine lawn to have a professionally-manicured look, your best bet is to hire a lawn care pro. Talented pros analyze your lawn to give it exactly what it needs to thrive.
Routine mowing, fertilizing, and weed control are a lot of work. Thankfully, local lawn care pros can handle all of your lawn’s needs, and their prices are probably more affordable than you think (especially considering the time and effort they’re saving you).
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