AGRICULTURAL EXTENSION SERVICE
UNIVERSITY OF FLORIDA
ST. AUGUSTINE LAWN GRASSES
By FRANK L. WILSON
Assistant Ornamental Horticulturist
St. Augustine grass is the most widely used lawn grass in
Florida because of its versatility. Some of the principal reasons
for the popularity of this grass include: dark green color, ability
to tolerate moderate shade, tolerance to salt spray and adapt-
ability to a wide range of soil types and conditions.
Fig. 1.-Bitter Blue St. Augustine (left) is more satisfactory as a lawn
grass than Roselawn St. Augustine (right).
There are many different St. Augustine grasses. These dif-
ferent grasses can be divided into 3 types, differentiated primarily
by the distance between nodes (joints on the grass runner where
roots and leaves arise). The node count method is a rough guide
for determining types. Internodes (the stem of the grass runner
between nodes) may be lengthened or shortened by cultural
practices or environmental conditions.
Bitter Blue (10 or more nodes per foot) is an improved se-
lection of St. Augustine grass. This type makes an excellent
lawn that has a dark green color. The leaves are shorter and
tend to grow more nearly horizontal than those of common or
Roselawn. This tendency and the shorter internode result in a
more dense turf. Bitter Blue has been the most popular St.
Augustine grass for many years but, contrary to popular belief,
it is not resistant to chinch bugs.
Floratine is a selection of Bitter Blue that is grown under
the Turf Certification Program of the Division of Plant Industry
of the Florida Department of Agriculture. Certified Floratine
can be identified by the Blue Certification Tag. One of these
tags accompanies each batch or load of certified grass that the
grower sells. This tag indicates that the grass is true to variety
and is free of noxious insects, diseases and weeds. The major
advantages of this variety are: it retains its dark green color
longer in the fall and it can be mowed much closer than other
St. Augustine grasses (Fig. 1).
Common St. Augustine (5 to 10 nodes per foot) is used ex-
tensively in Florida lawns. It is quite satisfactory. However,
it will not make as beautiful a lawn as Floratine or Bitter Blue.
Its leaves tend to grow vertically and the nodes are farther apart
than in the Bitter Blue type. Generally, the grass is of a lighter
green color than Bitter Blue.
Roselawn (1 to 5 nodes per foot) is used as a pasture grass
on muck soils in south Florida. Although sold as a lawn grass,
it makes a very poor turf. It has long, broad leaves and very
long internodes. The stems usually have a pronounced reddish
ESTABLISHMENT OF A NEW LAWN
The best seasons to plant St. Augustine grass are spring and
summer. However, in peninsular Florida it can be planted any
time of the year.
Remove Construction Debris.-Remove all concrete chips,
mortar, plaster and other construction debris from the lawn site.
Some contractors bury this debris in the yard. :This usually
causes a "trouble spot." The large quantity of lime present in
these materials makes iron unavailable to St. Augustine grass
and results in yellow areas of lawn.
Rough Grade.-The lawn grade should slope away from the
house to provide good surface drainage. Normally 'a grade of
1 to 5 feet (vertical drop) in 100 feet (horizontal) is adequate.
Terraces should be avoided if possible because it is difficult to
establish and maintain lawn grasses on steep slopes.
Add Soil Amendments.-Soil is the foundation for lawns.
Without a well-drained fertile soil it is more difficult and ex-
pensive to have a good lawn because of higher water and fertilizer
requirements. Since most Florida soils are low in native fertility,
it is usually necessary to: (1) bring in enough fertile topsoil to
cover the lawn area 6 inches deep or (2) add materials to increase
the water and nutrient holding capacity of the soil. If the first
alternative is chosen the next consideration is soil testing. The
latter alternative is the 1 most frequently used. While a satis-
factory lawn can be grown on native Florida soils, the addition
of soil amendments will reduce the effort and cost of maintenance.
Organic matter and colloidal materials increase the water and
nutrient holding capacity of sandy soils.
TABLE 1.-AMOUNT OF SOIL AMENDMENTS REQUIRED PER 1,000 SQUARE FEET
TO MAKE AN IDEAL SOIL FOR LAWN GRASSES FROM NATIVE SOILS.
Quantity for 6-Inch Depth
by Volume Cu. Yds. of Material Depth of Surface
per 1,000 Sq. Ft. Layer (in.)
Colloidal material 10 (good) 1.8 .6
15 (better) 2.8 .9
Organic matter .. 25 (good) 4.6 1.5
30 (better) 5.5 1.8
(1) Colloidal materials: Colloidal phosphate, some marls, red clay.
Gumbo or white clay is not suitable. Colloidal materials are highly desir-
able but are not always readily available throughout the state.
(2) Organic matter: Florida peat, imported peat, leaf mold, compost,
etc. Most of these materials are readily available throughout the state.
(Some organic materials such as Florida peat may contain large quantities
of weed seed.)
Soil Testing.-After the amendments have been spread and
mixed into the native soil or the topsoil has been spread, the
next step is to have the soil tested. To get a soil sample repre-
sentative of the entire lawn area, use a composite of several
individual samples. Each sample should be a slice of soil ap-
proximately 6 inches deep. Take 10 to 15 individual samples
from various locations within the lawn area. Mix them in a
bucket and take 1 pint of this mixture for analysis. A composite
sample from the front and from the back yard usually are suf-
ficient. Write your name and address on the sample and take
or mail it to your county agricultural agent for analysis and
Incorporate Fertilizer.-Apply enough fertilizer of a 1-1-1 or
similar ratio to provide 2 pounds of nitrogen per 1,000 square
TABLE 2.-AMOUNTS OF VARIOUS FERTILIZERS REQUIRED TO SUPPLY 2
POUNDS OF NITROGEN PER 1,000 SQUARE FEET.
Fertilizer Amount per 1,000 Sq. Ft. to
Provide 2 Pounds of Nirrogen
6-6-6 33 lbs.
8-8-8 25 lbs.
10-10-10 20 lbs.
Spread the proper amount of the chosen fertilizer uniformly
over the lawn site.
After soil amendments, fertilizer and dolomite (if recom-
mended) have been spread over the lawn area, mix them thor-
oughly into the soil to a depth of 4 to 6 inches. On small areas
use a shovel or spade to mix these materials into the soil, but
for larger areas a rototiller may be rented or the job may be
contracted to a lawn service company.
If a permanent irrigation system is desired, install it before
the finished grade operation is initiated.
Finished Grade.-The last step in preparing the soil is the
finished grade. For small lawns this may be done by hand raking.
Large areas may be smoothed by disking or harrowing. De-
pressions which show as a result of settling may be filled from
surrounding higher places. Walks and driveways should be
flush with the final lawn surface. After the finished grade is
completed, water the lawn area thoroughly.
In some cases soil fumigation is necessary to control nema-
todes and kill weed seeds. Due to high cost, most home owners
omit this practice. (For further information on soil fumigation
see your county agricultural agent.) The area is now ready for
Establishing the Grass.-St. Augustine grass is propagated
vegetatively by solid sodding, plugging or spot sodding and
Fig. 2.-Sprigging Floratine St. Augustine grass in a new lawn.
sprigging. Seed are not available. When the area is sodded
solid, blocks of turf (1 x 2 feet) are placed to cover the entire
area. This is the quickest but most expensive way to establish
a St. Augustine grass lawn. For plugging, the 1 x 2 foot sod
pieces are cut into smaller plugs, usually 4 to 6 inch squares, and
planted 8 to 12 inches apart in rows 1 foot apart. Sprigging is
accomplished by separating individual runners from the sod and
planting them end to end in rows 6 to 12 inches apart. A good
turf can be established more quickly by closer spacing of the
rows (Fig. 2).
TABLE 3.-AMOUNTS OF PLANTING MATERIAL (SOD) REQUIRED
TO PLANT 1,000 SQUARE FEET OF LAWN.
Method of Planting Amount of Sod to Plant
_1,000 Square Feet
4-inch plugs-planted on 12-inch centers.. 350 sq. ft.
Sprigged solid in 12-inch rows .................... 10 sq. ft.
Sprigged solid in 6-inch rows ..................... 20 sq. ft.
Water newly planted lawns every day until a new root system
is established (2 to 4 weeks) and then change to a regular water-
ing program (see management section).
Newly planted St. Augustine grass lawns should be fertilized
every 3 to 4 weeks at the rate of 1 pound of nitrogen per 1,000
square feet (see fertilization section). After 3 applications of
nitrogen, the regular fertilization program given under "Man-
agement" should be followed.
When weeds become a problem before the grass has covered,
the safest, although most expensive, control is hand weeding.
The use of chemicals for weed control is discussed on page 14.
MANAGEMENT OF ESTABLISHED LAWNS
After the lawn has been established, future success depends
largely on management. Considerable care and attention are
necessary in order to maintain an excellent turf.
Fertilization, watering and mowing are all interrelated. No
one factor is more important than another.
Fertilization.-Proper fertilization is often neglected by the
home owner. Too much fertilizer contributes to build-up of
thatch, while too little starves the grass. A healthy turf resists
weed invasion and many other adverse conditions.
The number of fertilizer applications per year depends on the
lawn appearance desired and location in the state. In southern
and central Florida, where the grass remains green most of the
year, 4 fertilizer applications per year are recommended. In
northcentral, north, and northwestern Florida, where St. Au-
gustine grass turns brown during the winter, make 3 applica-
tions per year. However, there may be exceptions to these
general recommendations, due to local conditions. Experience
will enable you to alter fertilization practices to fit the growing
conditions of your lawn.
TABLE 4.-SUGGESTED FERTILIZATION PROGRAM FOR ST. AUGUSTINE GRASS.
Feb.-March April-May September Nov.-Dec.
4 applications [ schedule 1 schedule 2 schedule 1 schedule 3
3 applications schedule 1 schedule schedule 1
1 1 2 or 3
Schedule 1, Complete Fertilizers.-It will require the follow-
ing amounts of fertilizer or similar analysis materials per 1,000
square feet of area to supply 1 pound of nitrogen:
6-6-6 ........ 16 lbs. 10-10-10 .... 10 lbs.
8-8-8 ...... 12.5 Ibs. 9-6-6 ........ 11 lbs.
Schedule 2, Organics.
a. Natural organic:
Sewage sludge, cottonseed meal, castor pomace, etc. Use
15 to 25 pounds of material per 1,000 square feet of area.
b. Chemical organic:
Use the following amount of material per 1,000 square feet
of area to supply 1 pound of nitrogen: Urea-formaldehyde-3
pounds, Urea-2 pounds.
Schedule 3, Chemical Nitrogen.-Use the following amounts
to supply 1 pound of nitrogen per 1,000 square feet of area:
Nitrate of soda ....................... 6 lbs.
Ammonium sulfate ............... 5 lbs.
Ammonium nitrate ................. 3 lbs.
Areas of the following dimension contain 1,000 square feet:
20' x 50', 10' x 100' or 40' x 25'.
Mixed fertilizers and natural organic materials can be applied
uniformly with a regular fertilizer spreader. The other materials
listed are more easily distributed with a cyclone seeder-type
Do not fertilize during mid-summer in south Florida. Lush,
fast-growing St. Augustine grass is more susceptible to army-
worm and sod webworm attack.
Organic sources release nitrogen more rapidly during the
warmer months than in cool weather.
After fertilizer has been applied, wash it off the grass into
the soil. Some fertilizers will cause burning if allowed to remain
in contact with grass blades.
Mowing.-St. Augustine grass should be cut at a height of
11/2 to 4 inches, depending on the type. Bitter Blue and Flora-
tine do best when mowed at 11/ inches; common should be mowed
2 to 21/2 inches; Roselawn should be cut 21/2 to 4 inches high.
The grass should be mowed often enough that no more than
one-half the leaf surface is removed at one time. To maintain
turf 2 inches high, cut the grass before it reaches 4 inches in
St. Augustine grass can be killed by continually mowing it
too closely (scalping). Close mowing damages the grass by
reducing the leaf surface so that the plant cannot produce suf-
ficient food and by exposing the stems to direct sun rays, which
Use a heavy mower for best results. Light mowers tend to
ride on the grass instead of mowing to the desired height, and
the cut is made a little higher with each successive mowing.
A sharp mower is necessary to insure a clean cut. Dull mower
blades tear instead of cut grass blades. This damage results in
frayed and split leaves, which cause the lawn to have a gray-
brown appearance. Rotary mowers are more likely to cause
this type damage than reel mowers.
It is desirable to remove grass clippings, either with a catcher
on the mower or by raking. Clippings that are returned to the
lawn contribute to thatch build-up.
Lawn mower shops, many garden supply stores and some
nurseries provide lawn mower sharpening services at a nominal
Setting the Mower.-The mower can be set at the proper
height by placing it on a smooth, flat surface such as a concrete
sidewalk and adjusting until the bottom of the blade (rotary
mower) or the top of the bed knife (reel mowers) is at the
Shade.-St. Augustine grass is the most satisfactory grass
for moderately shaded areas such as under oaks or Ficus trees.
In shaded locations mow the grass 1/2 inch higher than is gen-
erally recommended. Under shaded conditions fertilize, aerate
and water more often to offset competition from the tree roots.
Selective pruning of dense trees and removal of moss to allow
more light to enter the area is necessary in many cases and
usually results in better grass growth.
Watering.-Water is necessary in large quantities for the
lawn and should be applied as needed during the growing season.
It will be required more frequently in the summer than during
the winter. Don't be misled by light summer showers. Fre-
quently these rains wet only the soil surface and then evaporate
rapidly. Wilted leaves (rolled or curved toward the midrib)
indicate a need for water. When grass begins to wilt, water it
immediately. Apply at least 1 inch of water each application,
or enough to wet the soil to a depth of 12 inches. This can be
measured by allowing the sprinkler to run until 1 inch of water
has collected in a can placed approximately half way between
the sprinkler and the maximum water throw. Light sprinklings
every day which wet only the top 1 or 2 inches of soil are con-
ducive to the development of a shallow root system. Deep, in-
frequent watering stimulates the formation of a deep, healthy
During the summer or whenever lawn diseases are trouble-
some, water early in the day so that the grass will have a chance
to dry before night, thus avoiding a situation in which fungus
Improper mowing and excessive fertilization and watering
cause St. Augustine lawns to develop thick, spongy mats of
runners and undecomposed clippings. This mat is referred to
as thatch. It forms on the soil surface and in extreme cases
may be several inches thick. Under these conditions the root
system of the grass must grow downward several inches before
it reaches the soil. Thatch also reduces anchorage that normal
roots provide. The worst disadvantage of thatch is that it forms
a hard-to-wet cover over the soil. This interferes with water
penetration and also reduces penetration of insecticides and fungi-
cides into the grass where insects and diseases thrive.
The best way to renovate a heavily thatched lawn (more
than 2 inches) is to dig it up and replant. If the lawn has a
moderate thatch (less than 2 inches), there are several methods
of renovation that can be used.
Sanding or Topsoiling.-Applying sand to a lawn is not recom-
mended as a routine maintenance program. If a new lawn is
rough and needs leveling, "topsoiling" will aid in leveling it.
If the lawn is thatched, sanding or "topsoiling" will temporarily
correct the trouble. Continued applications of topsoil result in
a "layered" soil condition which retards water penetration. This
necessitates digging up and replanting the lawn within a few
years. The best topsoiling material is a soil identical to the one
in which your lawn is growing. When applying sand to a lawn,
cut the grass and remove the clippings, spread the sand or top-
soil as evenly as possible and work it into the grass using the
back of a garden rake or similar tool, then wash it down through
the grass. Add enough sand to cover all exposed roots and to
cover the thatch.
Scalping.-An occasional close mowing or scalping of St.
Augustine grass is beneficial because it reduces build-up of vege-
tative top growth. This operation can be done with a regular
rotary or reel type mower. Scalp the grass slightly by lowering
the height of cut 1/2 to 3/ inch. Repeated close mowings are
better than 1 heavy cut, which may severely damage the grass.
The best time for this operation is spring. However, it can be
done whenever the grass is in vigorous growth. After working
the thatch down, reset the mower to the correct height.
Verticutting.-Verticutting has been done successfully on St.
Augustine grass in several locations in the state. A verticut
machine is a type of "lawn mower" that has many vertical blades
which cut through the turf and pull out much of the thatch.
This method of renovating St. Augustine grass is in its infancy.
It has been used successfully, but proceed with caution. There
are many problems to be worked out before this method can be
generally recommended. If you use it, renovate a small area
and observe the effects before doing the entire lawn. The best
results have been obtained during the spring. Several cuttings
with the blades set 4 to 6 inches apart appear to give better
results than 1 cutting with the blades closer together.
Aeration.-It is difficult for plant roots, fertilizer and water
to penetrate very deeply into a compacted soil. Any method of
aeration that will loosen the soil will help this condition. Motor-
ized aerators can be rented from some tool rental businesses,
nurserymen or garden supply stores. Most grasses will respond
to aeration if the soil is compacted.
Insects.-Chinch bugs, armyworms and sod webworms are
the 3 major insect pests of St. Augustine grass, with chinch
bugs being the most serious. For further information on control
of these and other insect pests, see Extension Circular 213, "Home
Gardeners' Lawn Insect Control Guide."
Diseases.1-Two fungus diseases, brown patch and gray leaf-
spot, are responsible for the majority of disease problems in
St. Augustine grass. Brown patch is the more serious. In
Florida brown patch appears typically as a uniform partial dying
throughout an area of the lawn, although at times it may kill
small circular patches in the lawn. It may occur at any time of
the year but is most common during warm, humid weather.
Brown patch is most damaging to heavily fertilized turf. The
fungus which causes this disease is soil borne.
Fungicides for control of brown patch are listed in Table 4.
It is necessary to work the fungicide down to the soil to con-
trol brown patch. First, water the lawn thoroughly. Second,
apply the spray, directing it downward so the fungicide is forced
through the grass down to the soil. A second spray application
10 to 14 days later is usually necessary for best control.
TABLE 5.-FUNGICIDES FOR CONTROL OF BROWN PATCH FUNGUS.
Chemical Amt. per 1,000 Sq. Ft. of Lawn
Thiram ...................... ................. 4-6 oz.
PCNB .................... .................. 6-8 oz.
Kromad .......... .......... .................... 4-6 oz.
Mercury chlorides ........................ 1-2 oz.
'This section written in cooperation with Dr. R. S. Mullin, Extension
Gray leafspot is another important fungus disease that com-
monly attacks St. Augustine grass. This disease is most common
during the warm, rainy summer months. Gray leafspot attacks
the leaves primarily, but it may be found also on the stems.
Spots on the leaves are round to oblong and ash to brown in
color, surrounded by darker margins. The primary damage
caused by this fungus is a scorching or dying of infected leaves,
but it seldom kills the entire lawn. Heavily infested lawns have
a rather unthrifty appearance.
Gray leafspot is spread by fungus spores that are carried by
wind, water or mechanical means. To control this disease, it is
necessary to provide a protective coating of fungicide on each
leaf. This coating must be replaced frequently because of
weathering of the fungicide and new grass growth.
TABLE 6.-FUNGICIDES FOR THE CONTROL OF GRAY LEAFSPOT.
Chemical Amt. per 1,000 Sq. Ft. of Lawn
Thiram ............... ............................. 4 oz.
K rom ad ........................... ................. 4 oz.
Captan ................ ..... .. ........... 4 oz.
Chloranil .... ..... .. .............. .......... 4 oz.
During warm, rainy summer months a condition may occur
that is easily mistaken for a disease. The grass may have spots
covered with a gray to blackish soot-like material. This is the
fruiting bodies of a slime mold. If left alone, it will disappear,
or it can be washed off with a garden hose.
Nematodes.-Nematodes are microscopic worm-like organ-
isms that live in the soil. Several species damage grass roots.
In many cases the root becomes almost nonfunctional due to the
feeding activity of these pests. Since nematodes are microscopic
in size, it is necessary to observe symptoms rather than relying
on finding the pests.
Nematode-infested lawns resume growth in the spring but
usually become unthrifty and may stop growing when the nema-
tode population builds up during the summer. Lawns heavily
infected with nematodes are usually the first to wilt and die
during drought periods. Infected lawns may show stunting,
yellowing of leaves, easy wilting and very slow response to fertil-
ization. Root symptoms may include any of the following: root
browning, stubby or swollen root tips or short, many-branched
roots on which most of the root tips are dead (Fig. 3).
Fig. 3.-Top, healthy St. Augustine grass; bottom, nematode-damaged
grass. Note the short, stubby roots.
The simplest way to determine if nematodes are a major
problem in your lawn is to treat a small part (100 sq. ft., 10' x
10') of a suspected area with 1 of the nematocides listed in
Table 7. Wait 6 to 8 weeks and re-examine the treated area.
In heavily infested lawns the treated area will be much greener,
provided the lawn has received proper maintenance, particularly
If you have a nematode problem, you can reduce the numbers
of nematodes with chemicals. DBCP (Nemagon, Fumazone) and
VC-13 can be used to treat nematode-infected turf without dam-
aging the grass.
TABLE 7.-AMOUNT OF NEMATOCIDES REQUIRED FOR NEMATODE
CONTROL IN EXISTING TURF.
Material Pints per 500 Sq. Ft. I Gallons per Acre
DBCP (95%) ............. 1/ 5
VC-13 ......................... 1 20
Water the lawn thoroughly so that the soil is wet to a depth
of 6 inches. Divide the area into 500 square foot blocks and
complete the entire treatment of each block before starting the
next one. The nematocide can be applied with a lawn-hose gun.
Immediately after the material has been applied, water it into
the soil. Use at least 20 gallons of water on each 500 square
foot block. This is the most critical step. DBCP changes to a
gas very rapidly and, if not watered into the soil immediately,
will be lost. VC-13 also must be washed down into the soil to
Weeds.-Weeds do not usually constitute a serious problem
in established lawns if good management practices have been
followed. The best way to prevent weeds is to maintain a
healthy, vigorous turf. If you have weed problems, you can use
herbicides to help control them.
Lawn grasses must be in good health to withsand the effects
of weed killers. Grasses that have been weakened from lack of
water, fertilizer and either insect, disease or nematode infesta-
tion are much more easily damaged or killed by weed killers.
2,4-D and 2,4,5-T.-These materials will usually stunt and
sometimes kill St. Augustine grass, and they should be used
only as spot treatments. These chemicals will control many of
the broadleaf weeds that occur in lawns, but repeated applica-
tions are needed to control weeds that have fleshy roots. These
chemicals work best on weeds that are in active growth.
Do not exceed 1/2 pound of acid equivalent per acre for either
of these materials. If the material contains 4 pounds acid
equivalent per gallon, use 3/4 tablespoonful per 1,000 square
feet, or the amount listed on the product label. Do not exceed
the recommendations on the product label unless you are willing
to risk severe damage or the possibility of killing the grass.
In tests, 2-4-D butyric was not as damaging to turf grasses,
particularly St. Augustine grass, as other forms of 2,4-D. How-
ever, it did not control weeds as well as regular 2,4-D.
Do not use 2,4-D and 2,4,5-T on or around shrubs, trees,
flowers or any desirable broadleaf plants. Do not use these
chemicals on windy days when there is a possibility of wind drift.
Do not use equipment for spraying insecticides, fungicides or
fertilizers that has been used for spraying 2,4-D or 2,4,5-T.
Simazin.-Simazin2 is a new weed killer that will kill most
germinating broadleaf weeds, many grass seedlings and some
mature weeds. Two pounds of active material (21/2 pounds of
80% material) per acre or 27 grams (5 level tablespoonfuls) of
80% material per 1,000 square feet on mineral soils are recom-
mended. Four pounds of active simazin per acre are recom-
mended on organic (muck) soils. The soil should be moist at
time of application to obtain best results. This material usually
gives good weed control for a period of 3 to 6 months.
St. Augustine grass in good condition is not damaged by
recommended rates of simazin, whereas grass in poor condition
may be severely damaged or killed by the same dosages. It is
a good practice to fertilize, wait 2 or 3 weeks then apply simazin.
2At the time this circular went to press, TAT-42 was the only small
package product available that contained simazin. Several manufacturers
have indicated that they plan to package simazin in small quantities suit-
able for home owners. Several of these products will probably be granular
materials that can be applied with a fertilizer spreader. For most home
owners granular materials will be more satisfactory than sprays.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and United States Department of Agriculture, Cooperating
M. 0. Watkins, Director
For Your Future
COLLEGE OF AGRICULTURE
UNIVERSITY OF FLORIDA
The University of Florida College of Agriculture is
equipped and staffed to give you the best possible train-
Food Technology and
Animal Husbandry and
For more information write
Dr. Marvin A. Brooker, Dean
College of Agriculture
University of Florida