6 Best Fertilizer for St Augustine Grass | Greener & Lusher Lawn

Looking for the very best fertilizer to keep your lawn of St Augustine grass green and lush? Read along in this article that will outline all you need to know when looking for a fertilizer for St. Augustine, along with a list and evaluation of the top 6 fertilizers suited for your lawn. St. Augustine is a popular variety of warm-climate turf grass – and for good reason.

Its coarse texture and thick blades give dense coverage. However, its signature density and blue-green color are not going to look their very best without extra nutrients. 

The best fertilizer for St. Augustine Grass, like many others, will contain a relatively high concentrate of nitrogen. Nitrogen keeps the grass green and lush. The best way to apply nitrogen to your lawn is through a slow-release fertilizer to avoid multiple applications or burning the lawn. We recommend Milorganite

Aside from wanting the appearance of a lush, deep green lawn that would make the neighbors jealous, there are other good reasons to fertilize. Without fertilizer, St. Augustine grass is more prone to patchiness, bare spots, and thatch.

This means more room for weeds to move in and a nicer environment for unwanted pests. If your lawn is already severely impacted by weeds or pests, read more about how to get rid of them here.

Top 6 Best Fertilizers for St Augustine Grass

Below are the top fertilizers for St Augustine in 2020, tried, tested, and authentic. Any of these would be an excellent solution for your lawn – but continue reading our buyer’s guide below the list to find out which type of fertilizer suits your needs best.

1. Milorganite Organic Nitrogen Fertilizer

  • Famously used by professionals
  • Organic, non-synthetic
  • Slow-release

This organic fertilizer by Milorganite is nitrogen-rich, making it great for St. Augustine lawns. The NPK ratio is 6-4-0, meaning there is no Potassium, so it should be avoided in times or areas of drought. It also means the concentration of Nitrogen is relatively low and therefore has no chance of burning your lawn.

It should result in a darker green lawn that is less thirsty and easier to mow, but because it is slow release, the results may take some time. Slow-release is overall more economical and better for the lawn soil.

When looking to apply a granular, slow-release fertilizer, you will need a lawn spreader. Check the instructions on the bag in order to know what setting your spreader should be at when laying down fertilizer. If there is no rain in the forecast, you may need to water a day or so after applying it. Apply just once per season.

A few reviews do mention that this product has a smell, but that it dissipates quickly. When purchasing an organic fertilizer, this is only a good sign. This fertilizer can also be used to repel deer and rabbits.

2. Scotts Turf Builder Lawn Food

scotts lawn food
  • Encourages new green growth while defending and strengthening
  • High in nitrogen
  • Improves lawn’s ability to absorb water
  • both fast-acting and slow-release

This lawn food by Scotts is designed to grow your lawn thicker, greener, and more durable against heat and drought by improving your lawn’s ability to absorb moisture. It is a great option for all kinds of turf, including St. Augustine, which is looking patchy and pale. This fertilizer has an NPK ratio of 32-0-4, meaning it is very high in nitrogen, an essential nutrient for a lusher, greener lawn. A thicker lawn is an excellent defense against pests and helps to crowd out weeds.

As a granular fertilizer, this Scotts Lawn Food shows both fast results and contains slow-release particles for a longer-lasting solution than many of the liquid fertilizers. The very fine texture makes it quick to absorb. Use a regular lawn spreader to apply according to the directions on the package. Due to the high percentage of nitrogen, be sure not to apply in excessively hot weather, and water in lightly. Apply anytime throughout the growing seasons once every 6-8 weeks.

Be careful to always sweep any excess fertilizer that may have spilled onto sidewalks or patios back into the lawn.

3. Lesco St. Augustine Lawn Fertilizer

  • Good for greening up your lawn
  • A spring nutrient boost
  • High in iron

Lesco Turf Fertilizer is a solution tailored specifically for St. Augustine Grass. It has an NPK ratio of 24-2-11 plus it is high in iron, ideal for getting that maximum green color out of a faded lawn. Most reviewers seem really delighted with the results!

This fertilizer comes granular, so you will need a regular lawn spreader to apply. Water in well after application, but be wary of heavy rains as they may wash the majority of the granular away. The effects should be long-lasting. It is recommended to apply in the spring, in order to enjoy the full length of results!

4. Dr Earth Super Natural Organic Lawn Fertilizer

  • Organic and all-natural
  • Suitable for St. Augustine and many other grass types
  • Concentrated formula

Dr. Earth makes an excellent organic solution for your St. Augustine lawn. This brand is well known and loved for its use of natural ingredients and is safe for use around kids and pets. It may emit a slightly fishy smell, but that will last only about a day. This formula has an NPK ratio of 8-0-3, probably marginally lower to keep it safe and from burning your lawn.

Many reviewers swear by the product itself but have struggled with the nozzle and dispenser this product comes with – although it is mean to be convenient for those without a sprayer. Some retailers carry the product without the hassle of the nozzle. Whether you use your own sprayer or the one accompanying, be sure to follow the label to get the right ratio of concentrate to water.

5. Scotts EZ Patch Lawn Repair

  • Specifically formulated for St. Augustine Lawns
  • Combination mulch and fertilizer
  • Repairs bare patches 60% faster

This product from Scotts is an excellent solution for St. Augustine lawns that suffer from bare patches. This unique combination of mulch and fertilizer encourages surrounding St. Augustine to grow and fill in the bare dirt. Ready to use and easy to apply, it requires minimal effort – however, it is most effective when the bare patch is prepared.

The bare spot needs to be dug up, dethatched, and watered well before application. Once the spot is free from dead grass and roots, apply, keep watered, and wait. The results will show in about 3-4 weeks.

6. Simple Lawn Solutions Natural Liquid Fertilizer

  • Contains natural ingredients, including seaweed and fish
  • Ready to use, spray nozzle included
  • Quick results

With an NPK ratio of 16-4-8, this fertilizer is great for a well-established or new lawn of St. Augustine grass. This fertilizer’s claim to fame is feeding your lawn grass an optimal balance of nutrients, without any of the harsh chemicals.

This natural formula contains vitamin-rich, sea-based macronutrients such as seaweed and fish to feed your Bermuda grass lawn. This 32 oz bottle will cover up to 3200 square feet.

One great benefit of this product is it is ready to use, even if you don’t have fancy spraying equipment at home. The nozzle on the bottle is designed to hook up with any standard garden hose, so you can spray your lawn directly from the package, while it self-dilutes. Read the instructions carefully and make sure the hose is properly connected. 

Spray your lawn by hand with even, consistent passes – feel free to apply as often as monthly. Results will show quickly, but because this is a fast-acting liquid solution, it won’t last all season long. Fertilize spring through summer. Reviewers say they have had success with this product even in hot weather.

When and How to Apply Fertilizer on St. Augustine

If wondering when is the best time to fertilize St. Augustine grass, you also need to consider what zone you are in. Warmer climates (where frost isn’t an issue) can be fertilized almost all year round.

Cooler climates are recommended to start 3 weeks after the grass begins to green after winter. If using a soluble, fast-acting solution, you should apply once every 8 weeks. Granular, slow-release editions can be applied every 12 weeks, or even less as needed.

It is important when you apply any fertilizer to read and follow the directions. As a rule, dry fertilizers should be applied evenly and with a standard lawn spreader. Soluble or liquid fertilizers require a sprayer.

Again, an even spray will ensure the entire lawn benefits from the nutrients you are giving it. It is also key to water in the fertilizer once it is applied – you need it getting down into the roots, not sticking to the blade!

The only caution when applying fertilizer is to make sure not to adjust the ratio, and not to apply in hot weather. Avoiding these two mistakes will ensure your St. Augustine grass is well fed but not burnt out.

  • Do not apply nitrogen-rich fertilizer in heat over 85 degrees
  • Apply no more than 5 pounds of pure nitrogen per 1000 square feet

Buyer’s Guide: What to keep in mind when choosing a fertilizer for St. Augustine

Fertilizer for Newly Sodded St. Augustine

As you probably already know, St Augustine grass does not come in seed form and is therefore planted from sod. Because of this, even the newest-laid lawn of St. Augustine is slightly more mature than other varieties of turf that have just been seeded. This means you can go ahead and fertilize your brand new lawn without fear of stunting its development—however, a small word of caution.

The roots will not yet be established deep into the soil, and this means a slow-release or granular fertilizer may not be the best. Liquid fertilizer, on the other hand, will encourage the roots to reach down into the soil by soaking the lawn.

In conclusion, if asking yourself: Should I fertilize my newly sodded St. Augustine grass? The answer is yes! It will only help speed along the process of establishment.

Slow-release vs Quick release

It is always satisfying to see quick results when fertilizing a St. Augustine lawn. However, fast-acting, unfortunately, doesn’t always mean long-lasting. Quick-release or liquid fertilizers often boast deep and fast greening and growth, but will require several applications throughout the growing season. These kinds of fertilizers are an ideal choice if you have a family barbecue coming up, and you need the lawn to green up quickly.

A slow-release fertilizer is for those wanting to save their own time and effort. With application necessary as little as biannually, it means getting the job done and enjoying almost an entire growing season of beautiful turf without the hassle of spraying again and again. Also, slow-release fertilizers have less chance of burning the lawn, even when temperatures are high. 

Organic vs Non Organic

You might be looking for the best organic fertilizer for your St. Augustine lawn, due to kids and pets. It could also be you want to reduce harmful runoff, or some chemical products are banned in your region. Luckily, there are many fantastic options when it comes to organic fertilizers. You may have to withstand a bit of an odor, and organic is often more costly, but otherwise, you won’t find a downside.

Look for a quick, intense green for your St. Augustine grass? Maybe a synthetic solution will make more sense for you. If the lawn does not host a lot of foot traffic or pets, there is no real harm in using the chemicals – they often show faster, more apparent results.

NPK Ratios

Notice that the majority of granular fertilizers best for St. Augustine grass will have an NPK ratio of high-low-medium. This is indicated by the 3 numbers on the bag of fertilizer. Now, if the fertilizer is water-soluble, the ratio of nitrogen is often much higher, to show quicker results and account for runoff.

The NPK ratio stands for Nitrogen (N), Phosphorus (P), and Potassium (K). The number represents the percentage of the nutrient in the fertilizer; for example, a bag that says 14-6-4 will mean this fertilizer is 14% Nitrogen, 6% Phosphorus, and 2% Potassium.

The remaining 78% is added material that makes the fertilizer easier to spread. Each nutrient serves a different purpose in healthy plant growth:

  • Nitrogen (N): Aids in the production of lush, green leaves.
  • Phosphorus (P): Stimulates roots and helps development.
  • Potassium (K): Protects against disease.

This is why, on a well-established lawn of St. Augustine grass, a nitrogen-rich fertilizer is best. If the lawn has been recently sodded, a fertilizer ratio higher in phosphorus (the middle number) would be better suited. Too much nitrogen on new grass puts new growth at risk of burning out.

Conclusion and Takeaway

Fertilization is all about the right balance. If you don’t feed your St. Augustine grass, the nitrogen, iron, and other minerals it needs, it will never achieve that desired deep green. A thicker, healthier fertilized lawn will also crow out weeds and leave less room for pests. On the other hand, fertilize it too much, and you risk burning the lawn. Be sure to pick a fertilizer that is rich in nitrogen, but be careful not to apply more than 5 pounds of pure nitrogen to 1000 square feet of lawn. Spray or spread, depending on what method suits your needs best, then get ready to sit back and watch your St. Augustine grass as it thickens and gets greener.

Read on for more tips on how to get your St. Augustine grass to spread faster.