NC State Extension Publications

Introduction

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St. Augustinegrass is a fast-growing grass that has a medium-green to dark-green color and very coarse leaf texture. With proper maintenance, it provides a dense, lush lawn. A warm-season grass, it’s best in warm, humid areas not exposed to excessive or intense periods of cold weather. The Raleigh variety has the best cold tolerance and is best suited for the eastern piedmont and coastal plain.

St. Augustinegrass can be planted only vegetatively. It grows best in fertile, well-drained soils. It has excellent tolerance to shade, good tolerance to salt and heat, and moderate tolerance to drought. It does not tolerate heavy traffic or cold weather.

Since it grows fast, St. Augustinegrass needs to be mowed frequently. It should never receive more than 4 pounds of N per 1,000 square feet in a year. High fertilization rates and overirrigation can cause thatch buildup. Thatch can lead to other problems, such as disease and insect damage. Large patch can create brown circular patches up to several feet in diameter that usually warrant treatment. Chinch bugs are also often a problem, causing leaves to wilt and turn brown. Yellow spots are often associated with chinch bug activity.

St. Augustinegrass is sensitive to some postemergence herbicides, such as 2,4-D; however, some herbicides can be used at lower rates. Read and follow label directions carefully. Following the management practices in this factsheet is the best means of preventing and controlling problems in your St. Augustinegrass lawn. Continual loss of grass may mean that you need to select a turfgrass species that is better adapted to your particular yard. Contact your local Extension center for help identifying and solving turfgrass problems.

These suggested management practices will help you care for your St. Augustinegrass lawn throughout the year. Location, terrain, soil type and condition, age of lawn, previous lawn care, and other factors affect turf performance, so adjust the following management practices and dates to suit your particular lawn.

March Through May

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Mowing

Before green-up, remove dormant grass leaves by mowing to 212 inches with a rotary mower that has a newly sharpened blade. Maintain the lawn between 212 and 4 inches tall. The higher mowing height is usually more tolerant of shade and drought conditions. Leave clippings on the lawn.

Fertilization

It is best to submit a soil sample to determine nutrient requirements. Contact your local Extension center for details. Apply lime if the soil test report suggests it. Apply 12 pound of nitrogen (N) per 1,000 square feet in May or two weeks after green-up, whichever is latest. If you don’t have a soil test recommendation, use a complete (N-P-K) turf-grade fertilizer with a 3-1-2 or 4-1-2 ratio (12-4-8 or 16-4-8). Yellow grass may indicate an iron deficiency. Spray iron (ferrous) sulfate (2 ounces in 5 gallons of water per 1,000 square feet) or a chelated iron source to enhance color as needed.

You need to apply 1 pound of N per 1,000 square feet, so how much fertilizer do you need to buy? Divide 100 by the FIRST number on the fertilizer bag. (The first number always represents N content.) For example, if you’ve got a 10-10-10 fertilizer, divide 100 by 10 and you get 10. That means you need to buy 10 pounds of fertilizer for every 1,000 square feet of lawn.

Watering

Actively growing St. Augustinegrass requires about 1 inch of water per week, either from rainfall or supplemental irrigation. Sandy soils often require more frequent watering (12 inch every third day). Proper irrigation may prevent or reduce pests and other problems.

Weed Control

If crabgrass and goosegrass have been a problem, apply preemergence herbicides in mid to late February. Control broadleaf weeds as necessary with postemergence herbicides. St. Augustinegrass is sensitive to certain herbicides (for example, 2,4-D ), so follow label directions and use caution.

Insect Control

White grubs may be active at this time, but spring curative applications are not effective. Make note of areas with white grub activity and plan to apply a preventive application in the following spring or early summer. Specific timing will vary depending on white grub species, so plan to make an application when adult flight is at its peak. If drought symptoms or yellow spots occur in a sunny location, check for chinch bug activity (see the NC State Extension publication Chinch Bugs in Turf for specific recommendations). Push a coffee can (with both top and bottom removed) into the ground and fill it with water. Any chinch bugs present will float. Treat for chinch bugs if you find 20 or more chinch bugs per 1,000 square feet. For more information about a variety of turf pests, see the NC State Extension publication Insect Management in Turf.

Disease Control

St. Augustinegrass is extremely susceptible to large patch. Large patch is a disease that frequently develops during this period, especially during cool, wet weather. The pathogen is most active when soil temperatures decline to 80°F in the fall, yet spring development can be severe as well. Spring fungicides are warranted, with application beginning when soil temperatures reach 55°F for four consecutive days. Large patch is favored by excessive N in the fall and spring, poor soil drainage, overirrigation, excessive thatch accumulations, and low mowing heights. See the NC State Extension publication Large Patch in Turf for specific control suggestions.

Aerate

Heavy clay soils or heavily trafficked sections of lawn may benefit from aeration. If it is needed, aerate in late spring or early summer when the grass is actively growing and capable of recovery.

Renovation

Replant large bare areas in May (or when daytime temperatures are continually above 60°F) using plugs planted on 12- to 24-inch centers or sprigs (with space between plants) at the rate of 112 bushels per 1,000 square feet. One square yard of turf pulled apart is equivalent to one bushel of sprigs.

June Through August

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Mowing

Follow guidelines for March through May.

Fertilization

Apply 12 pound of N per 1,000 square feet in June and August and 1 pound of N in July. In the absence of a soil test, use a complete (N-P-K) fertilizer with a 3-1-2 or 4-1-2 ratio.

Watering

Follow guidelines for March through May.

Thatch

If thatch was 34 inch thick last summer, mow grass to 212 inches tall and use a power rake with 3-inch blade spacing.

Weed Control

Apply postemergence herbicides to control summer annual and perennial broadleaf weeds, such as prostrate knotweed (annual or short-lived perennial), spurge (annual), and lespedeza (perennial). Since St. Augustinegrass is sensitive to certain herbicides (2,4-D), follow label directions and use with caution. Do not apply herbicides unless weeds are actively growing and the lawn is not under drought stress. If crabgrass and goosegrass are present, make a note to apply a preemergence herbicide next spring.

Insect Control

If drought symptoms or yellow spots occur in a sunny location, check for chinch bug activity. Push a coffee can (with both top and bottom removed) into the ground and fill it with water. Any chinch bugs present will float. Treat for chinch bugs if you have 20 or more chinch bugs per 1,000 square feet. See the NC State Extension publication Chinch Bugs in Turf for specific recommendations.

Disease Control

Large patch activity is most likely limited during this time. However, gray leaf spot can develop now on St. Augustinegrass. Damage from gray leaf spot is rare in North Carolina, but small irregular patches could develop from persistent rain. Affected leaves will have small spots with gray centers surrounded by a dark purple or brown border. See NC State Extension’s TurfFiles for factsheets on these diseases.

September Through November

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Mowing

Follow guidelines for March through May.

Fertilization

St. Augustinegrass is generally not fertilized after mid September. September rate should be ½ pound N per 1,000 square feet or less.

Watering

Water to prevent drought stress while the grass is actively growing and after the lawn goes dormant to prevent excessive dehydration.

Insect Control

Follow guidelines for June through August.

Thatch

Check for thatch layer in early September. If the thatch layer is 34 inch thick, plan to de-thatch in the spring.

Weed Control

If crabgrass and goosegrass are present, plan to apply a preemergence herbicide next spring.

Disease Control

Large patch frequently develops during this period, especially during cool, wet weather. The pathogen is most active when soil temperatures decline to 80°F in the fall, yet spring development can be severe as well. Fall applications for preventive control is crucial for managing this disease. Preventive fungicide applications should start when soil temperatures decline to 80°F and continue monthly until soil temperatures drop below 60°F. Depending on the environmental conditions, there could be three applications in the fall. See the NC State Extension publication Large Patch in Turf for specific control suggestions.

December Through February

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Mowing

The lawn does not require mowing during this period. It may be necessary to pick up debris (for example, sticks and leaves). Do not try to remove excess debris by burning. This could injure the lawn and is a fire hazard.

Fertilization

Do not apply fertilizer or lime.

Watering

Although the lawn will be dormant, watering occasionally may prevent excessive dehydration during dry winters.

Weed Control

Apply broadleaf herbicides to control chickweed and henbit. St. Augustinegrass is sensitive to certain postemergence herbicides like 2,4-D , so follow label directions for reduced rates, and use with caution. Selected herbicides like atrazine and simazine can be applied in November or December to control annual bluegrass and several winter annual broadleaf weeds. Read the label and follow directions carefully.

Authors

Professor
Crop & Soil Sciences
Extension Associate - Turfgrass, NCSU Crop Science Dept
Crop & Soil Sciences
Associate Professor and Extension Specialist (Turfgrass Pathology)
Entomology & Plant Pathology
Extension Specialist (Peanuts & Turf) & Department Extension Leader
Entomology & Plant Pathology
Extension Associate
Entomology & Plant Pathology
Extension Specialist (Turfgrass/Forage Crop Weed Mgt)
Crop & Soil Sciences

Find more information at the following NC State Extension websites:

Publication date: July 8, 2021
AG-540

Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your local N.C. Cooperative Extension county center.

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