St Augustine Grass Care


st augustine grass care

This article is a comprehensive guide to complete St Augustine grass care.

In my ten years of performing St Augustine grass care for residential and commercial customers I have learned the secrets of St Augustine grass care and I will share them with you in this post.

The perfect St Augustine grass care is very simple and yet so many people struggle because they don’t understand 3 simple but critical principles in St Augustine grass care.

In order to achieve the very best St Augustine grass care you have to be able to understand how St Augustine lawn grows and be able to provide 3 simple cultural practices that are the key to a healthy, beautiful, thick and lush St Augustine lawn.


Most people think that St Augustine grass care is about a secret pest control fertilizer program that will miraculously make their grass green and lush.

When in fact pesticides and fertilizer are only 2 parts of great St Augustine grass care.

WARNING: This article is not for those that want an easy or simplistic answer to their St Augustine grass care problem because that answer does not exist. This post is only for those that want great St Augustine lawn care. I will share with you everything I know about St Augustine grass care and everything you’d ever wanted to know backed by over 50 years of turfgrass science. By the time your done reading this you should be an expert on St Augustine grass care.

Bare in mind there is no such a thing as a lawn type that will maintain itself easily or a perfect program, all lawns have inherent problems, cultural practices, pest, and nutritional needs. If you really want a great St Augustine lawn you have to be prepared to work at it. There is no easy solution.

The success of your St Augustine grass care program is going to depend on following theses guidelines.

The tendency is to become overwhelmed with so much information and requirements and give up, the secrete to this manual is Kaizen. Making continuous improvements over time.

If your St Augustine lawn is looking terrible don’t expect it will look good overnight because you applied something the truth is in most cases this can take a season, a year or longer to achieve but the important thing is to take a step in the right direction.

St Augustine Grass Care Background

St. Augustine grass is the most common lawn used in Florida; St Augustine grass [Stenotaphrum secundatum] is considered a warm season grass and is commonly adapted to the warm and humid subtropical regions of the US.

St Augustine grass is also known as Charleston grass in South Carolina. St. Augustine grass is sometimes called “carpet grass” in the Southeastern United States and in California.

St Augustine grows along the coastal areas from the Carolina’s, Florida, Louisiana, Texas and California.

St Augustine grass has been planted in Florida since as early as 1890 and in California since 1920.

St Augustine Grass Care Disadvantages

St. Augustine grass, like most turf grasses, has certain cultural and pest problems.

1. It requires water to remain green and healthy and will require supplemental irrigation during extended dry periods. About 1 inch of rainfall or irrigation per week. If your irrigation system is not on a timer to auto irrigate and you are too busy you will not have a great St Augustine grass care experience.

2. St Augustine grass has poor wear tolerance and does not hold up to repeated foot or vehicular traffic so if your kids love to play soccer you will not be able to keep it green and healthy. If you want a great looking St Augustine lawn you are not going to play on it.

3. During winter it will go into dormancy in parts of the state of Florida and it will turn a brown or tan color until spring. Since places like South Florida are subtropical and never experience a seasonal change like the Midwest or northern United States with its landscape color changes and dormant lawns and trees that appear to be dead.

Most people expect there landscapes to be green all year long when in fact it cant when temperatures drop into the 70’ 60s, 50’s and even to the 30’s plants react and start to change there colors, drop leaves in response to the change so a perfect green lawn all year long is not a realistic expectation.

St Augustine lawns will produces excessive thatch if you apply a high fertilization and irrigation programs, which will become a health problem for this grass.

Florida has three fertilization requirements for St Augustine grass care because of the 3 different climates in northern, central and southern Florida; in addition to that South Florida has Calcareous soils which are calcium carbonate rich because of our sedimentary limestone layer that makes our soil highly alkaline up to a ph of 8.5 to 9 in some areas.

South Florida has the highest fertilizer requirements in the state to 4 – 6 pounds of nitrogen per 1000 square feet per year which is about three times the northern Florida requirement in order to perform a correct St Augustine grass care.

4. St Augustine lawn has a coarse wide leaf and stems and therefore it does not grow as densely as some other grass verities or species this is why the right St Augustine grass care practices are so crucial. So if you come down from Kentucky you will think St Augustine lawn is a weed.

5. Southern chinch bug and white grubs are a major insect pest of St. Augustine grass which can cause considerable damage if not treated or prevented. So here is where a preventive routine pesticide application is required in a St Augustine grass care program is required, if you try to implement and IPM integrated pest management program or in other words spray it only when you have a problem you will have to put up with the yellowing and damage of the chinchbugs for months until its controlled and the lawn corrects itself. IPM is not for those that can’t put up with imperfections. IPM requires a realistic expectation and tolerance.

For more information on treating and preventing lawn insect pests see our post on lawn pest control.

6. St Augustine cultivars or varieties are also susceptible to diseases, such as gray leaf spot (Pyricularia grisea), large patch (Rhizoctonia solani), and take-all root rot (Gaeumannomyces graminis var. graminis), St. Augustine decline (SAD) (Panicum mosaic virus), Cercospora Leaf Spot (Cercospora fusimaculans).

Here is the fact on lawn disease, most of these diseases are soil borne which means they are in your soil you can’t get rid of them or kill them like a chinch bug or grub, once the bug is dead its dead. Fungus Pathogens are there to stay. The right St Augustine grass care is crucial to reducing lawn fungus susceptibility.

Fungus and bacterial pathogens become latent or dormant and become active when the perfect conditions exist for each type. Applications of fungicides are only made once the fungus is apparent as preventing them would require 6 to 12 fungicide applications per year at a cost 3 to 5 times higher than insecticides, so making routine fungicide applications is very costly.

With like any organism the building up of resistance is a problem there are not as many new fungicides that can control the pathogen on the market so overuse or unnecessary use can create a resistance problem. With fungus good frequent monitoring inspections are the norm.

Chances are your St Augustine lawn will have a perfect condition in every season of the year to experience a lawn fungus. Extreme temperatures changes such as 20 degree change in either direction can trigger an outbreak of the disease.

Temperatures in the low sixties will trigger one of five different disease, the change from winter to spring will trigger another and the changes from spring to summer with heavy rainfall will trigger another, finally extreme temperatures above 90 degrees will trigger yet another.

In other words any seasonal change will trigger a lawn disease. You will have to make between 3 to 6 lawn fungicide applications per year as part of a St Augustine grass care program in order to control fungus outbreaks.

Over fertilizing and under fertilizing will make your lawn susceptible to lawn fungus.

Improper mowing, scalping or allowing your lawn to over grown and then removing more than a third of the leaf blade will make your lawn more susceptible to lawn fungus.

Improper watering too much or too little will make your St Augustine lawn more susceptible to lawn diseases.

A healthy St Augustine lawn will naturally control weeds by crowding them out.

For more information on lawn diseases and how to treat and control them see our post on Lawn Diseases. https://www.naturepest.com/lawn-diseases/

7. Weed control can be challenging when trying to control persistent, grassy weeds like crab grass or sedges, and even broadleaf weeds because there isn’t one weed control product on the market that controls them all, you will have to use two or three different types of selective post emergent herbicides to control existing weeds and pre-emergent herbicides to prevent weeds from growing.

For more information on lawn weeds and control see our post https://www.naturepest.com/how-to-get-rid-of-weeds-in-lawn/

St. Augustine Varieties

In this section we will discus the three most commonly used varieties of St Augustine lawns

St. Augustine grass has been propagated for over 200 years, only a few varieties have evolved and none have been developed through grass breeding programs.

St Augustine Floratam and Palmetto

Floratam was released in a joint project by the University of Florida and Texas A & M University in 1973. Floratam is an improved St. Augustine grass. Floratam is the most widely used St. Augustine grass variety in Florida.

Floratam is a coarse-textured cultivar that has little cold and shade tolerance compared to other St. Augustine grass varieties. It does not perform well in areas that receive less than 6 hours of sunlight per day.

It grows enthusiastically in the spring and summer because it loves acid rains 5 to 5.5 ph.

When first released, it had been documented as chinch bug resistance, that has largely been diminished over time and now chinch bugs is now a major pest of St Augustine Floratam.

Palmetto was a variety discovered by a Florida sod grower in and introduced in the mid-1990s. It is also referred to as a “semidwarf cultivar” with a shorter growth habit and internodes than many other cultivars, but it is slightly larger than the dwarf St. Augustine grass cultivars.

It does very well in full sun or partial shade, but not in dense or complete shade. Most who install this variety under a heavily shaded are under trees will say I don’t understand why its dyeing my landscaper said it is shade resistant, shade resistant dose not mean it can handle complete shade only areas where it gets 4 to 6 hours of direct sunlight per day. It must get direct sunlight sometime during the day. And by direct I mean the suns rays must hit it directly if you see shade or shadows most of the day it will not thrive.

Palmetto is said to be drought tolerant, but research and experience shows that it has no greater degree of drought tolerance than Floratam. It is not resistant to insects and has similar problems with diseases in Florida’s humid environment.

Floratam and Palmetto are not tolerant of herbicides that contain Atrazine when applied at temperatures above 85°F. So weed control in the summer with weed and feed products are to be avoided in order to prevent lawn damage.

Floratam and Palmetto must be mowed at a height of 3–4 inches. Anything below that is considered “scalping” and considered detrimental to St Augustine lawn.

When I used to own a landscape maintenance company the only lawns that looked awesome where those that where mowed at 3 inches every week. All others looked like every other lawn that was mowed every two weeks and forget about those that only got mowed when the customer called.

Scalping is the #1 malpractice of landscapers and home owners. Scalping is the practice of mowing the lawn short so it will not grow too long between cuts, usually every two weeks in the summer and once a month in the winter. These practices are in place because of the property owner’s budget and time. Scalping slows down the growth because it removes too much of the leaf blade preventing it from photosynthesis which is the process of using sunlight and convert it to make sugar or glucose which is the plants natural food. The lawn is now stressed out and cant grow healthy roots and leaves making it susceptible to pests and diseases along with chlorosis that inability to produce chlorophyll which is the chemical that produces the green color.

If you want a great looking St Augustine lawn then you have to overcome this mentality and at best mow it weekly at 3 to 4 inches.

In my experience this is the hardest cultural practice to overcome, home owners and landscapers resist it like the plague, on average it takes me about 6 months of working with even those clients that want change and there landscapers to get them to correct this fatal practice.

The resistance from landscapers to correcting this practice is so entrenched that in most cases it is impossible to correct because the attitude is, “this is the way I have always done it and everybody does it this ways so I’m not going to change it and the customers is not willing spend the money for the additional services”.

I’ve even had landscapers tell me they will not even adjust there lawn mowers to raise there blades. At this point I have to be blunt and tell you that unless you correct this no St Augustine grass care program will ever give you results.

This is the equivalent of eating bad greasy foods, drinking alcohol in excess, smoking, working long hours, partying on the weekends and living on 5 hours of sleep only to end up in the hospital and demand from your doctor he give you a magic pill that will cure the way you are feeling so you can continue living without having to make any changes.

This is the way most St Augustine grass care programs are sold by lawn care companies as a secrete proprietary formulas that will make there lawn the envy of the neighborhood with out you having to do anything except sit back sip on lemonade and watch the grass grow, nothing could be further from the truth.

St Augustine grass care watering

The #2 most common cultural malpractice for St Augustine grass care is improper irrigation, watering at the wrong time, watering too often and watering too long are the most common mistakes people make when watering their lawns.

For newly planted lawns it is important to provide irrigation on the correct schedule. Short 5 to 10 minutes per zone of irrigation for 7–10 days after planting will help the grass establish without drying out. Irrigate only once a day to apply ¼–½ inch of water.

For most people trying to figure this out is too difficult, so ft you have a timer set it to everyday with one pin per zone if you have a digital timer set it for 12 to 15 minutes.

After this, frequency should be reduced to 2–3 times per week applying ¼–½ inch of water or 12 to 15 minutes per zone. In the hot spring months when temperatures are higher and no rain in sight you may need to increase your time to 2 pins per zone or 24 to 30 minutes per zone.

Temperatures affect water evaporation in soil so there will be less evaporation in January that in April when temperature are on average up to 10 degrees higher and no rain this makes a huge difference. Most people are too busy in there daily routines and these gradual weather fluctuations are not noticeable so irrigation systems are not adjusted accordingly leading to poor irrigation.

We use the NOAA Local Climate PRELIMINARY LOCAL CLIMATOLOGICAL DATA which keeps track of all weather conditions on a daily basis to make educated decisions

http://www.weather.gov/climate/index.php?wfo=mfl

Uneven turf with different elevations will require fine tuning to avoid dry areas or soaked areas. I have landscape with 6 zones that one zone is at only 4 minutes, will others are at 10, 12, 20 and so on.

It is recommended to install a rain sensor switch to your timer to automatically turn your system off on the rainy days to avoid over irrigation and conserve water. In new installations it may be required by law.

Only with taking the time to monitor and inspect can you establish the best St Augustine grass care irrigation program.

For our customer we inspect and manage the irrigation system and make the necessary adjustments to ensure optimal operation. Initially we take soil moisture readings to find trouble spots and make changes accordingly after that on every scheduled visit we inspect timer, heads and nozzles and make adjustments as required. We also make seasonal changes based on historical weather rain fall.

We take this so seriously that we do not allow anyone to make changes to the irrigation system, on occasions landscapers will go in a change the timer on us because they feel its wrong, so we take drastic measures and put a lock on the box and threaten to break fingers.

For more information, refer to ENH9, Watering Your Florida Lawn http://edis.ifas.ufl.edu/lh025

St Augustine grass care fertilizing

The #3 most common mistake in St Augustine grass care is improper fertilizing, most lawns are never fertilized properly if they are fertilized at all.

Fertilization is a vital part of St Augustine grass care, fertilizing is an after thought to most, fertilization is usually performed to compensate for bad mowing and watering cultural practices or as a correction only when the lawn looks bad.

Fertilization needs to be an integral part of your St Augustine grass care program.

St. Augustine grass is very responsive to nitrogen fertilizer in terms of color and growth rate. On sandy South Florida soils.

St. Augustine grass requires about 1 pound of nitrogen per every 1,000 square feet of lawn per month during the growing season to maintain good color and density.

Nitrogen requirements per year in Florida for St Augustine lawn care
Northern Florida 2-4 Pounds per 1000 sq ft per year
Central Florida 2-5 Pounds per 1000 sq ft per year
Southern Florida 4-6 Pounds per 1000 sq ft per year

With many states, counties and municipalities implementing fertilizer restrictions the 1 pound of nitrogen rule per 1000 square feet per month will come under severe scrutiny. Florida highest rate is maxed out at about ½ pound of nitrogen fertilizer per month.

In my experience if your cultural practices are good you can have a successful St Augustine grass care program at the ¼ to 1/2 pound of nitrogen fertilizer every 2 months even in our South Florida soils.

Too much fertilizer is bad for St Augustine lawn care
At rates higher than 1 pound per 1,000 square feet of lawn, St. Augustine grass produces a very lush growth that is highly susceptible to insects and diseases pests.

On heavier textured soils 1/2 pound of nitrogen every month is adequate to maintain good color and growth. When nitrogen fertilization exceeds the required rate thatch accumulation wich is also a problem

Late fall fertilization of St. Augustine grass is required to helps maintain color and density of the lawn during the winter and will promote early recovery of the grass in the spring.

To maintain St. Augustine lawn attractive, the lawn you should apply about 1 pound of nitrogen every 30 to 60 days from early spring through late fall.

St. Augustine grass is also sensitive to iron deficiency know as Fereric Chlorosis and readily develops chlorotic symptoms in alkaline or iron deficient soils. This deficiency can be corrected with foliar applications or iron sulfate or iron chelate. Soil applications of iron sources are less effective than foliar application in South Florida alkaline soils .

St. Augustine grass care requires potassium at about the same as for other turf grasses. The rate is about half the potassium as nitrogen is required to maintain a healthy growth. Potassium is required to increase root growth, help in cold tolerance and drought tolerance in St. Augustine grass.

Phosphorous requirements for established St. Augustine grass care are very low and generally met from the soil South Florida soils are rich in phosphorous. Occasionally an applications of a phosphorous may be required. In newly planted St. Augustine grass responds well to phosphorous fertilizers in terms of an increased rate of spread.

A good formulation for fertilizer St Augustine grass care would be 22-0-16 for more info on fertilizers see our post Understanding Fertilizers. or see http://www.growthproducts.com/pdfs_Literature/NitroKTurfProductHandouts.pdf

We have concluded 3 of the most important steps to a St Augustine grass care program, please use our other posts to here for the remaining steps which are insect control, disease control, weed control.

We wish you the best success in your St Augustine grass care program. Cheers!

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