How to Care for St. Augustine Grass
Many Southern homeowners choose St. Augustine grass as their lawn covering because of its ability to thrive in tropical and sub-tropical climates. St. Augustine grass (Stenotaphrum secundatum) spreads with stolons, often called runners, using a process called vegetative propagation. Each stolon forms its own root ball and blade set. The stolons weave together, forming a thick, carpet-like ground cover. Following a maintenance schedule keeps a St. Augustine lawn looking lush and deep green for many years.
St. Augustine Grass Types
Homeowners have several different types of St. Augustine grass to choose from. Some cultivars offer increased insect and shade tolerance. Homeowners should carefully match their yard's characteristics with the St. Augustine type's requirements. Popular cultivars include the following.
- Floratam: The most purchased turf grass in Florida and popular throughout the gulf coast region. Floratam needs five to six hours of sun per day but grows best in full sun. Homeowners with shady yards should consider other cultivars or ground covers. Set the lawnmower's cut height between three and four inches.
- Palmetto: Palmetto prefers full sun, but grows in partly shady areas. Its drought tolerance makes it a candidate for homeowners with local watering restrictions. Set the lawnmower height to approximately three inches.
- Seville: Considered a semi-dwarf grass, homeowners with Seville St. Augustine grass should set the lawnmower's cut height at 2-inches. Seville grows well in yards with shady areas. Regular insecticide applications help prevent chinch bug and webworm damage.
- Captiva: Known as a chinch bug-resistant St. Augustine grass, Captiva requires one-third less mowing than it's Floratam cousin due to it's slow growing nature. Captiva also performs reasonably well in shady yards. Set the lawnmower's blade height to about 2.5 inches.
The three numbers listed on a bag of fertilizer represent the nitrogen, phosphorus, and potassium percentages. To help understand these numbers, remember "up, down and all around." Basically, the first number helps the part of the plant above ground, the second number promotes below-ground root growth and the third number helps all parts of the plant.
St. Augustine lawns like fertilizers with a high nitrogen content during the growing season and a more balanced fertilizer throughout the rest of the year. Pay attention to and do not exceed the manufacturer's recommended application rate. The lawn only absorbs a certain amount of fertilizer; the rest washes away and becomes a potential groundwater pollutant. Apply the fertilizer in the morning and thoroughly water the lawn.
Tips for Managing Pests
Many insects like to live in St. Augustine grass. Common insects include fire ants, roaches, chinch bugs and grubs. Damage symptoms initially appear as irregular shaped yellow or brown areas that fail to respond to watering or fertilizer. Broadcast granular insecticide across the entire area.
Pests such as moles and armadillos dig for and eat many of these insects. These pests leave small piles of dirt or soft tunnels that collapse when stepped on. The digging disturbs the lawn's root system. Controlling these pests often requires a two-part solution. Spray an animal repellent to persuade the pest to relocate and apply an insecticide to kill their food.
Tips for Managing Weeds
A healthy, properly maintained St. Augustine lawn typically crowds out weeds and other grasses. The presence of a large amount of weeds in a mature lawn often indicates some type of weakness, such as improper fertilizing, insects or disease.
Only spread weed killers compatible with this grass and follow the manufacturer's recommended rate of application. Many professionals broadcast a St. Augustine-safe weed-and-feed type fertilizer during the spring and spot treat weeds during the other times of the year. When hand pulling a weed, grip the weed near the turf's surface and remove the root as well as the foliage. Treat crabgrass with a pre-emergent herbicide during the cool season months.
Increase the watering rate to two times per week as the weather warms. Begin the mowing cycle when the lawn starts to come out of dormancy. Do not bag the clippings. Instead, let them settle to the turf and decompose. The clippings turn into a slow-release organic fertilizer that returns nutrients to the soil.
Apply a "weed and feed" fertilizer in the early spring, about 2 to 3 weeks after the lawn starts to turn green. Only use a weed and feed fertilizer designed specifically for St. Augustine grass. Other types may burn or kill it.
During the summer months, a mature St. Augustine lawn requires water two to four times per week, depending on the soil's makeup and its ability to hold moisture. For instance, sandy soil drains faster and holds less nutrients than more dense soils. Avoid watering late in the afternoon or evening, as it promotes lawn fungus and diseases.
Apply a lawn fertilizer about 8 to 10 weeks after the spring application. Give the lawn an iron supplement 8 to 10 weeks after the fertilizer treatment, if needed. The iron supplement helps green up a pale-looking lawn.
Avoid herbicides when the temperature rises above 90 degrees. These chemicals damage heat-stressed lawns. When hand-pulling weeds, grip the weed stem near the soil and pull the root with the foliage.
Brown or dead patches often indicate either a pest or fungus infestation. Fungus typically spreads outward from the center with a uniform border, while pest damage often looks more spotty and irregular from a distance. Carefully inspect the edge of the damaged area, looking for insects or brown leaf spots. Apply either a fungicide or insecticide as soon as the first symptoms appear. Some manufacturers make products that treat both fungus and pests.
Consider the autumn months a transitional period for St. Augustine turf grasses. Warm season grasses start to loose their vibrancy as the growth-promoting long days and warm temperatures of summer gives way. Apply either an autumn blend or winterizing lawn fertilizer in early fall. These fertilizer types contain a more balanced nutrient blend than standard lawn fertilizer.
Cut the watering schedule back to one to two times per week, as the local weather dictates. The mowing schedule also transitions to a less intensive rate. Kill cool-season weeds with a St. Augustine-safe herbicide before they mature.
As a warm climate grass, St. Augustine varieties go into dormancy when average the soil temperature drops below 68 degrees. The leaf blades in a dormant lawn lose their pigment and they eventually start to brown. When the average soil temperature reaches 68 degrees the grass starts to come out of dormancy.
During this time of year lower the watering and mowing schedules to one to two times per month, depending on the average daily temperature. Only homes in southern zones where the turf does not go dormant require fertilizer and these homeowners should use a low-nitrogen winterizing fertilizer. To prevent new crabgrass, apply a pre-emergent herbicide once the average daily temperature rises above 65 degrees.
New Lawn Care
Prior to laying St. Augustine sod, rake or till the bare turf until the surface becomes loose and fluffy. Fill in any low spots with either top soil or a lawn soil. Lawn soil, a light-weight specialized soil, contains a fertilizer blend designed specifically for new lawns. Lay the sod or spread the plugs about.
Fertilize new grass with a slow-release starter fertilizer. This type of fertilizer promotes root growth. Never use a "weed & feed" type of fertilizer on new lawns until its' root system becomes well established. This type of fertilizer contains herbicides which, when applied too heavily, injures the new sod's delicate ends.
Water a new St. Augustine lawn two times per day for the first 3 weeks then cut back to a normal seasonal schedule. Turn the water on early in the morning and again in the early afternoon. Use enough water to keep the root system wet, but do not flood the turf. The second watering should start before the turf becomes arid and end before nightfall, limiting the new growth's susceptibility to disease or fungus.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
What insecticide do you use for St. Augustine grass?
I am not brand loyal. This year I used Bug B Gone. I like to broadcast a granular insecticide with a spreader.Helpful 16
What height do I cut St. Augustine Grass?
The perfect height really depends on the St. Augustine cultivar, however, you will be safe setting the blade at three inches.Helpful 15
How long after laying new sod for St. Augustine grass do I need to wait until it’s first cut?
It really depends on the amount of sunlight the sod gets and the time of year it is planted. Normally sod planted in full sun during the summer can be cut after 2 to 3 weeks, while sod placed in a shady area during the winter will likely remain dormant until spring. Do not mow until the roots establish and the runners have started to spread.Helpful 11
How long after laying new sod do I need to wait before spreading glandular insecticide?
I would wait until the roots start to become established.Helpful 9
What do you recommend to get rid of mole crickets from a lawn?
I spread a granular form all-purpose lawn pesticide about 3 times a year. There are products specifically for mole crickets, however I have always had good luck simply using a generic pesticide that kills all the bugs. I normally switch brands every time I need to buy a new bag. Last time I used Spectracide.Helpful 9
© 2018 Bert Holopaw