1. Turfgrass Management and
Culture
Jason Kruse, Ph.D.

2. Scope of the Turfgrass Industry
• Value added by the turfgrass industry
– 1982 Study estimated that the industry was valued
at $25 billion.
• At that time, Florida turfgrass industry estimated to be
$1.1 billion.
• Currently:
– Florida is #1 in US with 3.94 million acres
– Total revenues for Florida estimated at $7.82 billion
in 2007
– Total employment of 173,166 jobs

3. Florida Golf Course Revenues
2007
Total revenues $4.06 billion
Average revenue per firm: $4.4 million
Other Lodging
Recreation Other 2%
Retail 3%
Food/Beverage
2%
17% 11%
Golf
65%

4. Turfgrass Management
Golf Course Management

5. Turfgrass Management
Golf Course Construction

6. Turfgrass Management
Sports Turf Management

7. Turfgrass Management
Sports Turf Management

8. Careers in Turfgrass Management
Professional Landscape Management

9. Turfgrass Management
Professional Landscape Management

10. Careers in Turfgrass Management
Sod Production

11. Careers in Turfgrass Management
University Researcher

12. Turfgrass 101
• Identification of common warm-season
turfgrasses
• Establishment
• Cultivation/Mowing
• Fertilization
• Weeds/weed control

14. Bermudagrass
• Hybrid Bermudagrass (Cynodon dactylon X C.
transvaalensis)
– Description: Originated in eastern Africa in
1751 or earlier; sometimes called devil grass;
stolons and rhizomes; vernation - folded; ligule
- fringe of hairs; auricles - absent; collar -
narrow, continuous, hairy on margins; blade -
smooth or hairy on both surfaces, tapers
toward the tip; inflorescence - four or five
spiked branches.
14

15. Zoysiagrass
Bermudagrass
15

16. St. Augustinegrass
Stenotaphrum secundatum [Walt.]
Kuntze.
• Identification
– VERNATION: folded
– LIGULE: fringe of hairs, 0.3 mm long
– SHEATH:
– AURICLE: absent
– COLLAR: broad, continuous, narrow to form a
short stalk at the base of the blade.
– LEAF BLADE: flat, 4 - 10 mm wide, smooth on
both surfaces, with a blunt tip, 90-degree angle
from sheath at the collar.
– GROWTH HABIT: stoloniferous.
16

17. St. Augustinegrass
Stenotaphrum secundatum [Walt.]
Kuntze.)
17

18. Japanese Lawngrass
•
Zoysia japonica Steud.
Identification
– VERNATION: rolled
– LIGULE: fringe of hairs, 0.2 mm long
– SHEATH: short, flat, smooth
– AURICLE: absent
– COLLAR: broad, continuous, with long hairs.
– LEAF BLADE: flat, 2 - 4 mm wide, stiff, long hairs
distributed along smooth adaxial and, sometimes,
abaxial surfaces, sharply pointed.
– GROWTH HABIT: rhizomatous & stoloniferous
(stolons with husk like sheaths.
18

19. Japanese Lawngrass
Zoysia japonica Steud.
19

20. Bahiagrass
Paspalum notatum Flugge
• Identification
– VERNATION: rolled or folded
– LIGULE: membranous
– SHEATH: compressed, split
– AURICLE: absent
– COLLAR: broad
– LEAF BLADE: flat to folded, 4 - 8 mm wide,
margins sparsely hairy toward base.
– GROWTH HABIT: rhizomatous & stoloniferous
20

21. Bahiagrass
Paspalum notatum Flugge
21

22. Seashore Paspalum
Paspalum vaginatum Swartz.
• Identification
– VERNATION: rolled
– LIGULE: membranous, 2-3 mm long, pointed.
– AURICLE: absent
– COLLAR: broad, continuous
– LEAF BLADE: flat with margins rolled inward, 2
– 4 mm wide, margins sparsely hairy toward
base.
– GROWTH HABIT: rhizomatous & stoloniferous
22

23. 23

24. Mowing
Mowing is the periodic removal
of part of the turfgrass shoot.
24

25. 25

26. 26

27. 27

28. 28

29. 29

30. 30

31. Mowing Equipment – Reel Mowers
• Best for highest turf quality because of its
scissor-like cutting action.
• Consists of a rotating reel cylinder equipped with
blades and a stationary bedknife.
31

32. 32

33. 33

34. Mowing Equipment – Rotary Mowers
• A horizontal blade cuts the grass blade by
impact.
• Does not produce as sharp a cut as a reel
mower, but is acceptable for turfs cut above 1".
• Most dangerous turf equipment at home.
34

35. 35

36. 36

37. Mowing Equipment – Rotary Mowers
 Keep blades sharp and balanced.
 Dull blades tear instead of cutting cleanly
which exposes more tissue to drying and takes
turf longer to recover.
 Mow parallel on slopes - not up and down.
 Clean area of trash and debris before attempting
to mow.
 Observe all safety precautions - keep hands and
feet clear.
 Do not mow wet, tall grass.
37

38. Mowing Equipment – Sickle Bar
• Sickle Mowers Mowers
– For haying operations.
– Used on tall grass, mainly on roadsides.
38

39. Mowing Equipment - Flail Mowers
• Vertical rotation but safer than horizontal rotary
because of free swinging blades.
39

40. Mowing
• Most basic, yet most important cultural practice
that can be used to provide desirable turf.
• Turfgrasses can be mowed close to the ground
due to the terminal growing point (crown) being
located at or just below the soil surface.
– Regrowth from cell division and elongation
takes place below the height of the mower
blade.
40

41. Mowing
• Turfgrass growth habit is affected by mowing.
– Frequent mowing increases tillering and shoot
density.
– Mowing decreases root and rhizome growth
because food reserves, following mowing, are
utilized for new shoot tissue development at
the expense of root and rhizome growth.
• Improper mowing exacerbates the problem
41

42. Mowing is a STRESS
• Effects of Mowing
– Water loss
– Disease Development
– Decreased Carbohydrate Storage
– Increased Shoot Density
– Small Shoots
– Decreased Root and Rhizome Growth
42

43. Variables Influencing Mowing Height
• Species/Cultivar
– Each turfgrass species has an adapted range
in which it tolerates mowing.
• This range will be lower than the
recommended mowing height .
–Mowing below the recommended
mowing height, but within the range of
tolerance, requires a higher level of
maintenance to maintain a healthy
turfgrass stand.
43

44. Variables Influencing Mowing Height
• Species/Cultivar (cont.)
– Mowing below the tolerance range will result
in rapid deterioration of turfgrass quality.
• Excessively close mowing heights will
decrease the:
–total leaf area
–carbohydrate reserves
–root growth
44

45. Variables Influencing Mowing Height
• Species/Cultivar (cont.)
– Close mowing creates a situation where the
plants are unable to produce enough food to
meet their own demands.
• Turfgrass plants will be more susceptible to
drought, high temperature, and wear injury.
45

46. Variables Influencing Mowing Height
• Species/Cultivar (cont.)
– Mowing above the tolerance range will reduce
tillering and cause matting of the grass.
• Reduced tillering results in fewer and
coarser plants, while matted grass creates
a good microenvironment for disease
development.
–Also increases thatch accumulation,
which creates a need for higher
maintenance.
46

47. Variables Influencing Mowing Height
• Root-to-Shoot Ratio
– Turfgrasses have a ratio of shoot to root
tissue that is optimal to support growing
grass.
• If turf is mowed too low at one time, this
results in an imbalanced ratio with more
roots available than the plant
physiologically requires.
–The excess roots are then sloughed off.
47

48. Variables Influencing Mowing Height
48

49. 49

50. Variables Influencing Mowing Height
• Use
– The use of the site will dictate how short or tall
to mow.
• Putting green = 5/32" or lower.
50

51. Mowing Heights
Species/Variety Use Mowing Height (in)
Tifgreen Golf Greens 5/32 to 3/8
Tifdwarf Golf Greens 1/8 to ¼
Ultradwarfs Golf Greens 1/3 to 1/10
 Champion
 FloraDwarf
 TifEagle
Tifway (419) Golf Tees 3/8 to 1¼
Tifway II Fairways
GN1
TifSport
Common Bermudagrass Fairways 1 to 4
Roughs
Bahiagrass Roughs 3 to 4
St. Augustinegrass Out-of-Play areas
51

52. Mowing Frequency
 Determine the mowing frequency by the grass
growth rate, not by any set schedule.
 Remove no more than one-third of the total leaf area
at any one mowing.
 For example, if you mow a St. Augustinegrass
lawn at 3”, the grass should be 4” tall.
 Removing more than one-third shocks the turf,
which may result in temporary thinning.
 Reserve carbohydrates are utilized for shoot
regrowth, which will deplete the stored
carbohydrates and reduce the capability of the
turf to withstand environmental stresses.
52

53. Variables Influencing Mowing Height
• Season (Time of year)
– Spring - turfgrasses tend to have a more
prostrate growth habit.
• They can be mowed closer than during
other seasons without consequence.
• Close mowing in the spring:
–controls thatch;
–increases turf density;
–removes excess residues or dead leaf
tissue;
53
–promotes earlier green-up.

54. Variables Influencing Mowing Height
• Season (Time of year)
– Summer - turfgrasses tend to have a more
upright growth habit and are healthier if the
mowing height is raised to compensate for it.
• Increases turf rooting, reducing watering
needs and stresses imposed by increased
nematode activity.
54

55. Variables Influencing Mowing Height
• Season (Time of year)
– Fall
• Mowing height may need to be raised to
reduce the chance of low temperature
damage during winter (north Florida) and to
provide cushion for grass crowns in winter
where bermudagrass is dormant.
55

56. Variables Influencing Mowing Height
• Shade
– Under shady conditions, grass leaves grow
more upright in order to capture as much of
the filtered sunlight for photosynthesis as
possible.
• As a result, mowing height for grasses
grown under these conditions needs to be
raised at least 30%.
–If mowing height is not raised, grasses
grown under shaded conditions
gradually thin out and die. 56

57. Clipping Removal
• It has been taught that clippings should be
removed because they contribute to thatch.
– Clippings contribute very little to thatch
development because clippings are primarily
water and cellulose that decompose easily.
– Only remove long clippings that remain on top
of the grass.
• Excess clippings shade the turfgrass and
create a microenvironment that favors
disease development.
57

58. Grass Clippings
• Clippings are a source of nutrients.
– Clippings provide nutrients 3-6% N, 2-3% K,
0.5-1% P.
• If clippings are removed, application of
additional fertilizer to compensate for those
nutrients is needed.
58

59. Grass Clippings
• Clippings should be removed only when they are so
heavy that they smother the grass or interfere with the
playing surface, such as on golf greens.
• Clippings pose an environmental problem.
– Most municipal landfills no longer accept them.
• 14-25% of material sent to landfills is lawn
debris.
• Clippings from greens should be disposed of properly to
prevent undesirable odors near the playing area and to
prevent fire hazards.
– Composted clippings can be used as a ground mulch
in flower beds or inaccessible areas. 59

60. Fertilization

61. Fertilization Frequency
• Ideal fertilization program would be to apply very
small amounts of essential nutrients each week
or two during the growing season.
– Rates can be continually adjusted up or down
depending on the turfgrass response.
• Extremely expensive
• Totally impractical
61

62. Fertilization Frequency
• The presence and availability of essential plant
nutrients determines the minimum fertilization
frequency.
• The number of fertilizations can be minimized
with the use of slowly available nitrogen carriers.
62

63. Fertilization Timing
• The proper timing becomes more critical as the
number of applications per growing season is
reduced.
– Warm-season Turfgrasses
• Late spring / early summer best - plants
actively growing.
• Late summer / early fall fertilization may
reduce their cold-hardiness and result in
some winterkill.
63

64. 64

65. Fertilization Timing
• Cool-season Turfgrasses
– Fall fertilization best - minimizes disease
problems, promotes better fall color retention,
and earlier spring green-up.
– Early-spring / Mid-spring may encourage
diseases and favors weed growth.
– Early-summer / Mid-summer fertilization
should be avoided to reduce stress levels.
65

66. 66

67. Fertilization Rate
• General rule: Never apply more than ½ lb. of
quickly available nitrogen per 1000 ft2, or 1 lb. of
slowly available nitrogen per 1000 ft2.
– As temperatures increase, decrease rate.
– Lower mowing height, decrease single
application rates
• Individual shoots are smaller and thus more
susceptible to injury from large
concentrations of fertilizer nutrients.
• Close-cut grass is often so dense that
fertilizer particles cannot fall into the turf; 67

68. Methods of Application – Liquid
• Foliar feeding
Sprayers
– Spray volumes less than 0.5 gal/1000 ft2 or
lower.
– Significant quantities of the nutrients are
absorbed directly by the turfgrass leaves, thus
the name.
– Only low rates of fertilizer (1/8 lb N or Fe /
1000 ft2) should be applied to avoid burn.
68

69. Methods of Application – Liquid
•
Sprayers
Liquid Fertilization
– Spray volumes of 3 to 5 gal / 1000 ft2 are
used.
– With this method, much of the fertilizer is
washed off the foliage, and root absorption
occurs.
69

70. Granular Spreaders - Drop Spreader
• Drop spreaders can provide very accurate and
uniform application of granular materials.
• Fertilizer exits through a series of openings at
the base of the hopper.
• The rate can be changed by adjusting the size of
the openings.
70

71. Drop Spreader
71

72. Drop Spreader
Application
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73. 73

74. Granular Spreader - Rotary
(Centrifugal) Spreaders
• Very efficient for fertilizing
large areas.
• Fertilizer falls through one
or more openings of
adjustable size onto a
rotating plate at the base of
the hopper and is propelled
away in a semicircular arc.
• Most effective with uniform
sized particles.
74

75. How To Properly Apply Fertilizer
• Use a deflector shield
when fertilizing near
water bodies or
impervious surfaces.
75

76. Fertilizing Around Water
“Ring of Responsibility” 76

77. 77

78. 78

79. Thatch Control / Cultivation
• What is it?
– Thatch is composed of an intermingled layer of
living and dead stems, stolons, rhizomes, and
roots between the green vegetation and the soil
surface.
79

80. Thatch Control / Cultivation
• What is the difference between thatch and mat ?
– Mat is thatch intermixed with mineral matter.
– Thatch may be transformed into a mat as a
result of top dressings.
– Like thatch, mat develops between the green
vegetation and the soil surface.
– Mat develops on putting greens and other
areas of turf that have been top dressed.
80

81. 81

82. Thatch Control / Cultivation
• What causes thatch?
– Thatch is basically a residue problem that
occurs in most turfgrasses.
• Thatch accumulates and persists largely
because the tissues occurring in the thatch
contain decay resistant lignin.
–Tissue components such as cellulose
and hemicellulose decompose rather
quickly.
»Failure to remove clippings after
mowing does not cause thatch 82

83. Thatch Buildup
• Attributed to:
– Species & Cultivars
• Different species produce thatch at different
rates.
–Perennial ryegrass produce less than
most other cool-season grasses.
–St. Augustinegrass, hybrid
bermudagrass and zoysiagrass may
have excessive thatch accumulation,
while centipedegrass and bahiagrass
also form thatch, but at a slower rate. 83

84. 84

85. 85

86. 86

87. Thatch Buildup
• Attributed to:
– Improper management
• Mowing
–In general an increase in mowing height
will cause an increase in thatch.
• Excessive Fertilization
–High levels of nitrogen fertilizer results in
increased thatch accumulation.
87

88. Thatch Depth as Influenced by
Mowing Height
88

89. Why is thatch a problem?
• Only when thatch becomes excessive is it a
problem.
– Moderate thatch accumulation can
• Cushion turf,
• Improve wear tolerance, and
• Moderate soil temperatures.
89

90. Why is thatch a problem?
• Excessive thatch results in numerous problems.
– Foot printing
• Excessive thatch promotes a spongy
surface that can foot print, or even worse
disrupts the smooth, firm surface needed
on putting greens.
– Scalping
• When the thatch becomes excessive, the
turf gets puffy and becomes prone to
scalping from mowers which causes severe
injury. 90

91. Foot Printing
91

92. Scalping
92

93. Why is thatch a problem?
• Localized Dry Spot
– Thatch has profound effects on water
relations in turf.
• Under normal conditions thatch will allow
rapid percolation of water through its large
pores.
• Upon reaching the thatch-soil interface,
however, downward water movement slows
resulting in a temporary water table within
the thatch.
93

94. 94

95. Why is thatch a problem?
• Localized Dry Spot
– As evapotranspiration proceeds and moisture
in the thatch zone is depleted, water from the
underlying soil (finer textured medium) does
not move readily into the dry thatch (coarser
textured medium).
• As a result a thatchy turf will often wilt even
though the soil beneath has adequate
water.
95

96. 96

97. Why is thatch a problem?
• Localized Dry Spot
– Thatch becomes hydrophobic once it dries
out.
• When this occurs uniform wetting from
irrigation is impossible because water fails
to penetrate the surface.
• One solution to localized dry spots is the
addition of wetting agents which reduce the
surface tension and allow water to
penetrate thatch.
97

98. 98

99. 99

100. No Wetting Agent
Wetting Agent
100

101. Why is thatch a problem?
• Wet Spots
– On heavily thatched athletic fields subject to
traffic and wear during the wet season, thatch
may become compressed and stay saturated.
• When this occurs, the thatch often acts as
a sponge and impedes water movement
into even a porous rooting medium.
101

102. Why is thatch a problem?
 Reduced Drought, Heat, and Cold Tolerance
 Extreme differences in bulk density between
thatch and the underlying soil reduce drought
tolerance since root growth occurs primarily in the
thatch zone and not in the compacted soil.
 Without excessive thatch, root and rhizome
growth occurs in the soil and roots can draw
moisture from a larger, more stable reservoir.
 Turfgrass crowns, stolons, and rhizomes tend to
be elevated and grow in the thatch instead of the
soil.
 This brings them into closer proximity to the
temperature extremes.
102

103. Why is thatch a problem?
• Poor Fertilizer Response
– Thatch is a poor environment for
microorganisms to live.
• Upon fertilizer application, the particles
become trapped in the thatch layer.
–Fertilizer activity that is dependent of
microbial breakdown will be limited.
• Poor Color Retention
– Thatch free turf retains color longer.
103

104. Poor Fertilizer Response
104

105. Why is thatch a problem?
• Increased Pest Problems
– Thatch layers provide environments for some
disease and insect organisms to live.
• Brown patch, dollar spot, and leaf spot
diseases as well as sod webworms are
examples.
• Reduced Effectiveness of Overseeding
– Overseeding turfs with high thatch levels very
difficult because seed is planted into the
thatch, and not the soil. 105

106. Thatch Control – Mechanical
Removal
 Vertical mowers for dethatching generally utilize
either solid blades, flail blades, or spring tines.
 A vertical mower has a series of knives vertically
mounted on a horizontal shaft.
 The shaft is rotated at high speeds and the
blades slice into the turf and rip out thatch and
other debris.
 Dethatching machines are available in a variety
of sizes.
 The objective is to remove as much thatch as
possible without damaging the turf.
106

107. Thatch Control – Mechanical
Removal
• Vertical mowing is quite disruptive
– Timing is important - it should be timed to
precede a period of major vegetative growth.
• Cool-season grasses = early spring
• Warm-season grasses = early summer
– Improper timing can result in weed invasion
because the turf is open.
107

108. Power Raking
108

109. 109

110. Power Raking
110

111. 111

112. Power Raking Promotes Early Green-up
112

113. Vertical Mowing (Verticutting)
• Vertical mowing meets different objectives
depending on the depth of the knives:
– Slight - grain is reduced when knives are set
to just nick the surface of the turf.
– Shallow - breaks up cores following
aerification, facilitating a topdressing effect.
– Deep - stimulates new growth when stolons
and rhizomes are severed and results in
removal of accumulated thatch.
113

114. 114

115. Post Verticutting Care
 Soil and thatch should be dry or turfgrass injury will
be more extensive, since moist conditions
encourage excessive plant material to be removed.
 Following verticutting, debris should be removed and
the area immediately irrigated.
 Apply 0.5 pound of quick-release nitrogen per 1,000
ft2 to encourage rapid recovery.
 A 30-day period of favorable growth is needed for
the turf to recover.
 Therefore, the last vertical mowing of the season
should be timed at least four weeks before the
average frost.
115

116. Grooming
• A groomer is a miniature vertical mower mounted in
front of the reel cutting unit of a greensmower.
– Each time the turf is mowed with this unit, the turf
is lightly vertically mowed (or groomed).
• Improves the surface by standing up the leaf
blades before mowing – removing surface
grain.
116

117. Grooming
Groomers are easily knocked
out of adjustment and much
caution should be used.
117

118. Thatch Control
• Biological Control
– This approach utilizes management
techniques that create an environment that is
conducive to thatch decomposition.
• Topdressing
• Core Aerification
• Spiking/Slicing
• Grooming
118

119. Topdressing
• Adds a thin layer of soil or root zone mix to the
turf surface which is then incorporated by
dragging or brushing it in.
– On newly established turf, topdressing:
• partially covers and stabilizes the newly
planted material;
• smooths gaps that result from sodding; and
• minimizes turfgrass desiccation.
119

120. Topdressing
• On established turf, topdressing:
– smooths the playing surface;
– controls thatch and grain;
– promotes recovery from injury; and
– can change the physical characteristics of the
underlying soil.
120

121. Belt-Type Topdresser 121

122. Topdressing
 Frequency & Amounts:
 Following coring and heavy verticutting, moderate to
heavy topdressing amounts are used to help smooth
the surface, fill coring holes, and cover exposed roots.
 Irregular playing surfaces or soil profile renovation will
require frequent and relative heavy topdressing.
 Rates range from 1/8” to 1/4” (2 to 4 yds3 of soil per
5,000 ft2.)
 Soil Physical Characteristic changes -
 Heavy topdressing program following numerous
deep core removal operations over a period of years
is required.
122

123. Improper Topdressing
Layers Developed 123

124. Topdressing
• Materials:
– Topdressing material should match the
construction material.
• The only difference may be the absence of
organic matter.
–Enough organic matter is produced over
time by turfgrass plants to cover future
needs.
124

125. Topdressing
• Materials
– Pure Sand:
• Sandy soils tend to produce harder (firm)
playing surfaces that do not hold
approaching shots well.
• Sandy soils also require an increase in
nutrient and water application since they
drain so well and localized dry spots may
develop if the sand becomes hydrophobic.
125

126. Topdressing Home Lawns
126

127. Topdressing Home Lawns
127

128. Aerification or Coring
• Is the removal of small soil cores
or plugs from the turf surface.
– Normally 1/4” to 3/4” in
diameter, however, larger
sizes are now available.
– 2” to 4” depths with cores
spaced on 2” to 6” centers.
128

130. Aerification or Coring – Benefits
 Relieves soil compaction
 Allows deeper, faster penetration of water, air,
fertilizer, lime, and pesticides.
 Allows for release of toxic gases (CO2 and CO)
from the root zone.
 Improves surface drainage.
 Penetrates through soil layers that develop form
topdressing with dissimilar materials.
 Thatch control by stimulating microbe
environment.
 Increased rooting.
130

131. Aerification or Coring -
Disadvantages
• Temporary surface disruption.
• Increased turf surface desiccation as roots are
exposed.
• Coring holes provide a habitat for insects
(cutworms).
131

132. Slicing
• A slicer has a thin, V-shaped knives bolted at
intervals to the perimeter of metal wheels that
cut into the soil.
– Turf is sliced with narrow slits about 1/4”-wide
2” to 4” deep.
– Much faster than coring and does not interfere
with turf use since there is no removal of
cores.
– Performed on fairways and athletic fields and
other large, trafficked areas during mid-
summer stress periods when coring may be 132
too injurious or disruptive.

133. Spiking
• A spiker provides an effect similar to a slicer.
– The penetration is limited to approximately 1”,
however, the distance between perforations
along the turf’s surface is shorter.
• Spiking causes less disruption than coring.
– Used for:
• breaking up soil surface crusting;
• breaking up algae layers; and
• improving water penetration and aeration.
133

134. Thatch Control
• Integrated Cultural Practices
– Fertilization
• Avoid excessive application of fertilizer.
– Maintain pH of soil
• A pH of 7.0 is ideal for maximum microbial
activity and decomposition.
– Proper Watering
• Maximum decomposition occurs if the soil
is at optimum moisture, not too wet or too
dry.
134
– Mowing Practices