St Augustine grass (Stenotaphrum secundatum) is a fast growing, widely-adapted, warm season grass.
It grows in a wide variety of soils and pH levels, comes in several cultivars and is the most common turf grass grown and used throughout the state of Florida. It is also used throughout the southeastern United States.
A properly maintained St Augustine lawn will produce a dense, lush carpet of medium to dark green/blue-green color. It does best growing in rich, well-drained soil, in a warm humid climate. Exposure to cold temperatures should be limited, without excessive or intense duration.
The Advantages of St Augustine
- Produces dense turf of green, dark green, blue green color
- Adapts to a wide variety of soils
- Overall good salt tolerance
- Establishes quickly
- Makes a quick lawn from sod
- Can be started from sod, sprigs or plugs
- Some cultivars handle shade better
Disadvantages of St Augustine Turf
- Requires water to remain healthy and green
- May require additional irrigation during dry periods
- Under heavy irrigation or fertilizer schedules it can produce thatch
- Does not handle excessive heavy foot or vehicle traffic
- Goes dormant some areas during winter turning tan or brown
- Does not grow as densely as other grasses due to coarse wide leaves
- Chinch bugs can cause serious damage
- Susceptible to take-all root rot, leaf spot and brown patch
- Weed control can be difficult
Cultivars of St Augustine
There are several cultivars available. Below is a listing of the more popular ones used in Florida lawn care and across the Southeast.
Maintenance Calendar for St. Augustine Grass Sod
March Through May
As spring arrives and your St Augustine begins to turn green, it’s time to start mowing the grass. During the winter months your grass may turn brown and tempt you to set your lawn mower lower to remove all the “dead” grass before the active growing season.
Bad choice… St Augustine spreads by stolons or stems on top of the ground. Mowing the grass low can scalp and damage the stolons, it also discourages deep rooting.
Mow your grass often, at 2.5 to 4.0 inches, removing no more than ⅓ of the leaf blade. By mowing more often during the growing season you’ll avoid build up of grass clippings. Unless the grass coming out of the mower is leaving clumps in the yard, collecting the grass is not required.
Before applying fertilizer to your lawn it is usually a good idea to get your lawn’s soil tested (every 2 – 3 years is fine). Apply lime if the soil test recommends it. Apply 1 pound of nitrogen per 1,000 square feet approximately 3 weeks after after your grass begins to green up. Do not apply more than 3 pounds of nitrogen per 1,000 sq ft per year.
See Calculating Fertilizer below
During the spring season St Augustine seldom needs irrigation due to the the spring rains. However, if the lawn is established apply irrigation on an “as-needed” basis. If leaf blades turn a blue-gray color, look wilted or curled, begin to fold over or show foot-prints from walking in the grass – it’s time for irrigation.
Don’t over-water! Apply ¾ to 1” of water per week if needed. Follow all local water restrictions that may apply.
See Determining Irrigation Rates below
If crabgrass has been a problem, apply preemergence herbicides labeled for St Augustine grass by March 1 – (earlier in warmer areas like South Florida)
Remember if weeds are actively growing, preemergence herbicides will not control them.
When using postemergence herbicides, beware St. Augustine grass is sensitive to certain herbicides like 2,4-D. Never apply postemergence herbicides (e.g., atrazine), when the air temperatures are over 85°F or the turf is under moisture stress.
Use and apply postemergence herbicides with caution and ALWAYS follow the instructions on the label directions.
Make sure you have correctly identified the weed before treating and grass with a post or preemergence chemical.
During the spring and fall months you may find brown grass, in circular patches called “brown patch” fungus. Brown patch usually happens during humid, warm weather and is fueled by excessive nitrogen. Fungicides may provide control.
A better “method of control” is to reduce irrigation and nitrogen, improve drainage and air movement through the soil.
The number one insect pests for St Augustine grass is the southern chinch bug. If you notice yellow spots or drought like symptoms in sunny locations – check for chinch bugs. Lawn grub worms can also be a problem.
Checking for Chinch Bugs
Take a coffee metal can and remove the top and bottom. Push the coffee can into the area you think may have chinch bugs. Fill the can with water. If chinch bugs are present – they should float. Generally, it is recommended to hire a professional to treat your St Augustine turf for chinch bug.
If your lawn is in need of some renovation, the spring time is the time to re-sod the areas or plant plugs on 6 to 12 inch centers.
June Through August
During the hot summer months, unless your lawn is stressed due to drought conditions, mow your grass every 5-7 days. If drought conditions exist, mow less often.
Also during the “growing” summer months, apply 1/2 to 1 lb of nitrogen per 1,000 square feet. However, because of the rapid growth during this time of the year, I like to split the application in half.
Apply the first application around mid-June and follow with the second application around the beginning of August.
Remember: DO NOT apply more than 3 lbs of nitrogen per thousand square feet per year.
Watering your lawn early in the morning is always recommended. St Augustinegrass can survive for long periods without rainfall or irrigation. However, good moisture in the soil will help your St Augustine lawn retain its color during the summer months. A weekly watering of 1 to 1 ¼ inches should allow the water to penetrate 4 – 6 inches into the soil and provide ample moisture.
Lawn in sandy soils will need more frequent watering. When watering lawns in clay soils, remember the soil “accepts” the water slowly.
Water until the “runoff” starts, water the next zone and come back and water the zone again until the water has been able to penetrate the clay soil to th desired depth.
If grass looks dark and blue-gray, wilted, and curled or folded leaf blades and foot-prints show, your St Augustine is saying it’s time to irrigate.
Never forget: You can help prevent or reduce pests and other problems with proper irrigation practices.
Areas, exposed to heavy traffic – foot or machine – could possibly benefit from lawn aeration.
Check for thatch. If thatch depth exceeds 0.75 inches, the best control is to remove with a power rake.
Early summer is the best time for any aeration or cultivation as the St Augustine has plenty of time to recover.
Do a thorough walk over your lawn looking for any drought like symptoms or yellow spots showing up in sunny locations. If they are found – check for any chinch bug activity. Use the “coffee can” method described above. If chinch bugs are found – treat the area. It’s recommended to seek a lawn professional for treatment.
To control summer perennial and annual broadleaf weeds apply post-emergence herbicides. Always follow the label and directions in application. Make sure the post-emergence herbicide is labeled for St Augustinegrass.
DO NOT Apply any herbicides if:
- Lawn is under stress
- Weeds are not actively growing
Check for large patch and gray leaf spot disease.
If your lawn is in need of some renovation, replant any large areas in Late-May, re-sod the areas or plant plugs on 6 to 12 inch centers.
September Through November
Continue mowing St. Augustinegrass following the same guidelines as June-August, mowing every 5 to 7 days and less when the lawn is drought stressed.
Generally, St Augustine grass can be fertilized between 2-6 times per year, all depending on your location.
Due to the climatic range and geographical locations of where St. Augustine grass grows fall fertilizer applications differ depending on location.
In northern areas where St Augustine will go dormant, no fertilizer is needed. However, in south Florida, a year-round fertilization program is acceptable.
Apply lime if a soil test recommends.
Follow the irrigation guidelines for March – May. If your St. Augustine grass is dormant, periodic irrigation may still needed when dry, windy conditions occur for extended periods.
The exception: To prevent desiccation newly planted lawns or sod should be watered during this period.
Do regular checking for large patch fungus.
Check for crabgrass. If present make plans and mark your calendar to apply a pre-emergence herbicide in the spring.
December Through February
During this period mowing will most likely not be required, except in the very southern areas like south Florida. However, you can do some lawn clean up by, picking up any debris (sticks, rocks, leaves, etc.).
Fertilizer should not required during this period. If you have not taken a soil sample (every 2-3 years is fine) and had your soil tested, now is a good time to find out your lawn’s nutrient makeup and requirements.
Be sure to specify your lawn species. Also, labs are slow so a soil test during this period is perfect.
Any newly planted lawns or sod should be irrigated and watered to prevent desiccation. Again depending on location, watering may be required.
Do not keep the soil wet as dollarweed and sedges thrive in wet soil conditions.
For the control of chickweed, henbit and others apply a broadleaf herbicide labeled for St. Augustine grass. Always follow the label directions carefully on rates and always use with caution.
Tips On Calculating Fertilizer & Irrigation
To determine the amount of fertilizer product required to apply 0.5 pound of nitrogen per thousand square feet, divide 0.5 by the first number (%) in the fertilizer ratio.
For example, for a 20-5-5 fertilizer (containing 20% nitrogen), divide 0.5 by 0.20 (NOTE: 20% = 0.20).
The result is 2.5 pounds of product per thousand square feet.
To determine the quantity of water supplied by a sprinkler system, place several straight-sided cans (e.g., tuna fish or cat food) in each irrigated zone. Run the zone and record the amount of time required to fill the cans to a level of 1/2- or 3/4-inches.
Each zone will most likely vary in the amount of time required to produce the same quantity of water.
Now program into the irrigation controller the time needed to produce the required irrigation rates to make the sprinkler system automated.