landscape Li hting
Dewayne L Ingram and Dennis E. Buffington U-i ; -
P.A,. z -,'. Fn.'
Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences
University of Florida, Gainesville, John T. Woeste, Dean for Extension
TABLE OF CONTENTS
Landscape Lighting ........... .. ........................ 1
Lighting Techniques. .................. ................... 2
Developing a Lighting Plan ......... ....... ............... 7
Lighting Fixtures. ................... .................. 10
Installation Considerations for a Low Voltage System .............. 12
Landscape Lighting Costs ................. . . . ..... 15
Dewayne L. Ingram is Associate Professor and Woody Ornamentals Specialist,
Dept. of Ornamental Horticulture, Institute of Food and Agricultural Sciences,
University of Florida, Gainesville, Florida.
Dennis E. Buffington is Professor, Dept. of Agricultural Engineering, Institute
of Food and Agricultural Sciences, University of Florida, Gainesville, Florida.
Dewayne L. Ingram and Dennis E. Buffington
Landscape lighting is essential for safe and secure movement of people
onto or within the landscape and can extend the functional period of the out-
door living area. Well-lighted entrances, driveways, and walkways express
hospitality, allow easier identification of visitors, and discourage trespassers.
Steps, stepping stones, ramps, and passageways between buildings should be
lighted for safety. Service areas need illumination for household chores such
as putting out trash and bringing in firewood. Lighting for specific outdoor
activities should be considered.
Dramatic garden lighting extends the enjoyment of landscape features into
evening hours when outdoor living areas are most often used. Evening out-
door activities requiring light include dining, playing, exercising, entertain-
ing, cooking, and socializing. Outdoor lighting can also extend the perspective
of an indoor room to the outdoors by illuminating attractive features such as
specimen trees or shrubs, sculptures, water features, or some structural fea-
tures. In this way, landscape lighting lets people be indoors without leaving
the garden behind.
Landscapes in general and landscape lighting specifically should be de-
signed with people in mind. The designer must determine how to illuminate
areas to provide safety and security, accentuate primary features in the land-
scape, and enhance human enjoyment. Glare from lights at eye level reduces
visibility. Eye level height should be considered about 5 feet (1.5m) for stand-
ing adults and 3/2 feet (1m) for sitting areas and areas accessible by wheel-
A basic rule in landscape lighting is to use indirect lighting and avoid direct
"head-on" lighting of plants and objects. Indirect lighting is achieved when
the light source is hidden from view and only the effects of light are seen as
it is reflected from one or more objects or surfaces. Indirect lighting is more
useful than direct lighting to illuminate smaller areas and objects of interest.
Basic techniques in landscape lighting include down-lighting, up-lighting,
silhouette-lighting, shadow-lighting, cross-lighting, and graze-lighting.
Several of these techniques can be used in an interesting and functional land-
scape lighting design.
Down-lighting is usually directed straight down from above objects to be
illuminated (Figure 1). Down-lighting can be used close to the ground to pro-
vide indirect light to walks and steps or can be positioned high above a patio
or children's play area to provide illumination of a larger area. Down-lighting
through open trees or shrubs can create interesting shadow patterns on patio
or lawn surfaces. Positions of lights that impinge on neighboring property
should be avoided.
Up-lighting is accomplished by positioning the light source below the ob-
ject to be illuminated. Up-lighting provides little light for people movement
and is used primarily to accentuate plants or objects (Figure 2). Lights po-
sitioned above eye level in trees, or at ground level and pointed upward can
illuminate interesting branching habits. Ground level lights for up-lighting
should be obscured from direct view by use of plants, the light fixture itself,
or by angling away from the primary direction of view.
Silhouette and shadow-lighting are created primarily by lighting objects
from one side and are used to accentuate the form of objects. Silhouette-
lighting is achieved by lighting the background (for example a fence or wall)
so the dark object is viewed against an illuminated surface or by back-light-
ing the object so that it is viewed against a dark background (Figure 3).
Shadow-lighting creates definition and interest by using side-lighting to cast
a shadow of an object, such as a shrub with interesting branching habit, on
a patio, fence, or wall (Figure 4). Effects of an interesting branching habit
can be further multiplied by casting shadows in more than one direction with
Cross-lighting is simply lighting an object from opposite directions, either
from front to back or side to side (Figure 5). Light fixtures for cross-lighting
are usually positioned near the ground and the light intensities from the two
fixtures are generally different.
Graze-lighting is used to accentuate the textural surface of objects (Figure
6). For example, interesting exterior siding of a house can be accentuated by
concealing lights in a shrub or flower bed 2 or 3 feet (0.6 to 1 m) from the
building and directing the light so that it grazes the wall. Textural qualities
of bark, foliage, and fences can also be accentuated with graze-lighting.
Landscape lighting should bring out the texture and shape of objects being
illuminated. Light radiating from between an object and a viewer and shining
directly on the object makes it appear flat or two-dimensional. Indirect light
reflecting off the surfaces) of objects defines the texture and shape of the
object and accentuates interesting features.
The texture, size, and growth habit of plants should dictate the type of in-
direct lighting to accentuate interesting features. Up-lighting is best for plants
that are open and cross-lighting at sharp angles is best for densely foliated
plants. Open, fine-textured trees are best up-lighted while tight, columnar
trees should be cross-lighted in a circular pattern.
Proper light intensity for specific fixtures depends on the purpose of the
light and the atmosphere one wishes to create. Variations of light intensity
from a single light placement can create a variety of effects such as a subtle,
mysterious atmosphere or a safe, secure feeling. The reflective quality and
color of objects to be illuminated determine the proper light intensity. Watt-
age of light bulbs used in the landscape varies from 20 to 150 watts. Thirty
to sixty watt bulbs are most common, but 100 to 150 watt bulbs may be used
for up-lighting a giant oak or when illuminating a large area from 15 to 25
feet above ground.
Purchase of a dimmer switch may be justified if light intensity needs to be
adjusted depending upon the desired atmosphere or the changing use of an
area. Subtle lighting in a sitting area in the garden creates a low-key atmo-
sphere that stimulates a person's imagination to fill in the details. However,
this subtle light is lost when viewed from a lighted porch or indoors. The light
intensity required while sitting in the garden may be 20 times less than when
the goal is to view the garden from indoors. In such cases the ability to adjust
light intensity appropriate to the use is desirable.
A transition in light intensity from indoors to outdoors should be planned
so that a person's eyes can adjust gradually to changes in light as he moves
from one area to another. The distance from the light source to the object to
be illuminated also affects proper light intensity.
Water adds interest to the landscape and this feature can be accentuated in
the evening hours by proper light placement. The most effective light for a
fountain or waterfall comes from a fixture in the water. The light fixture
should be placed approximately 3 inches (7.5 cm) below the water surface
and should be trained on the waterfall or spray. Shallow ornamental pools
may be lighted from the side to create interesting reflections on the water and
make it appear darker and deeper. Swimming pools should be illuminated
V ... .
from inside the pool. Light fixtures placed on the sidewall near the bottom
can illuminate the whole pool, and lights placed in the peripheral area in-
crease the feeling of security around the pool during evening hours.
Steps should be lighted in such a manner that shadows are not cast on the
steps. Generally, lights positioned to illuminate steps from the side or built
into the rise of each step eliminate shadows cast by one step on another.
Colored lights can be used in the landscape, but they should not be over-
used and they must be skillfully chosen. Warm colors such as red and orange
look rather unnatural outdoors and should be used only when red and orange
tones dominate an area. Blue emphasizes blues and greens in the landscape
and creates an element of mystery. Greens brighten greens and reduce the
effects of warm colors as does blue light. Clear light brings out the intensity
of all colors and accentuates textural differences. Several different colors of
lights located in a given area may produce a circus atmosphere that appears
busy and unorganized.
Developing a Lighting Plan
A landscape lighting plan tor a typical single-family residence is presented
in Figure 7. Refer to this plan as steps and considerations of developing a plan
A lighting plan should be an extension of the landscape planting and struc-
tural features. Start the planning process by identifying the access areas to
the house, service areas. play areas, and the locations indoors and outdoors
from which the landscape will be viewed in evening hours. Then. identify the
landscape features that could serve as points of interest if illuminated. Elec-
trical service locations) should also be identified at this time.
The first priority for lighting is to provide light for access to the house from
the driveway and or street. This can be accomplished b\ strategically placing
low down-lighting on the walks in areas where the walk changes directions
and spaced close enough to provide adequate illumination of the walking sur-
face (Figure I). If only the walk is lighted. visitors or family members who
approach the house walk on an illuminated path but the peripheral area is
dark and insecure. Lighting from fixtures on the house along the walk. at
the entrance, or in nearby trees help persons feel more secure as they
approach the house.
Lighting work and play areas should have second priority. Children's play
areas are best illuminated by down-lighting positioned at least 14 feet (4 m)
high in trees or on poles. Lights in trees are more easily concealed than lights
on poles during daylight hours and the cost of poles is eliminated. Lights
should be spaced so that the light beams overlap at least 7 feet (2 m) above
the ground. The same is true tlr general work areas, but more light intensity
and specifically directed illumination may be required tor some work activ-
ities such as outdoor cooking. Light intensity required in play and work areas
depends upon the activities most often planned in these areas.
Patios. decks, or porches may be illuminated by down-lighting as well. but
indirect lighting of surfaces and objects in and around these areas create a
more tranquil. interesting atmosphere tor conversation, entertaining, and
dining. The view from outdoor and indoor living areas can be brought to life
by indirect lighting. Illumination of the large specimen crape myrtle in the
raised planter near the patio as shown in Figure 7 creates a point of interest
lir indoor and outdoor viewing. If lights in the children's pla area are turned
oft. the back portion of the rear yard becomes a dark background for the
lighted crape myrtle.
Once the lighting fixtures have been positioned on the plan. an electrical
system to connect these fixtures to the electrical service locations) must be
planned. Existing electrical service outlets may be utilized in some cases, or
additional outlets may need to be installed. Lights that would be on or off at
the same time could be on a common circuit, however, multiple circuits allow
operation of groups of lights independently. Location of fixtures relative to
each other and the electrical service may also dictate the number of circuits
desired. Electrical lines in circuit # 1 (Figure 7) have been split at a junction
after the first light fixture to allow wire to be placed on both sides of the
sidewalk. This planning means wire will have to be routed under the sidewalk
at only one point. Planning of electrical wiring systems requires special
training and in most cities and counties a licensed electrician must approve
all electrical installations. However, such code restrictions may not apply to
low voltage (12 volts) installations beyond the transformer, or if the home-
owner does the wiring.
Note: It is unwise for lighting to be installed by anyone other than a licensed
electrician unless the individual is fully aware of all safety principles in-
volved in electrical wiring.
Several lighting manufacturers specialize in landscape lighting fixtures
and systems. Although most are low voltage systems, 110 voltage systems
are also available. Kits of various types are available that allow homeowners
to install systems themselves, but such kits allow little or no flexibility in fix-
ture selection or wiring layout. Individual components can be purchased
which offer greater design flexibility, but separate components generally cost
more than when sold in a group package.
Up lighting (silhouetting trunk and lighting canopy)
Down-lighting Chidren Play Ar
Pine 1 Pine
F,rewood 'Graze-lighting \ P,~e
Work Shop (fixtures in soffit)
nd Trumpet Vine Large Oak
(n- raised planter)l
Circuit No. 4
Circuit No. 3 Cirt
S P Down-lighting
Circuit No. 5
O Pine P
Circuit No. 1 II Circuit No. 2 3
I/ i gustrum Down lighting Oak
Oak 150 Watt
[ 100 Watt
< 60 Watt
O 30 Watt (Mushroom fixture)
Interior lighting system
Lighting fixture designs range from strictly functional types to those
which are truly works of art. Simple functional fixtures designed primarily
to hold a light bulb should be placed inconspicuously out of direct sight.
Other fixtures add decorative qualities to the landscape while providing use-
ful light as well. Between the two extremes of styles, there are designs to
meet most outdoor lighting needs. Several styles of light fixtures are illus-
trated in Figure 8.
There are several "do-it-yourself" low voltage landscape lighting fixtures
that can be constructed in the typical home workshop. Fixture style is limited
only by human imagination, but a few simple designs are presented in Figure
9. All kinds of shields can be made for use with simple light bulb holders. For
example, a section of galvanized sheet metal duct six inches in diameter and
18 inches (45 cm) in length can be painted dark brown or green on the out-
side, flat black inside, and can be placed over an adjustable bulb holder at-
tached to the ground. The duct section shields the light bulb from view and
directs the light upward (Figure 9A). A 6- or 8-inch (15 or 20 cm), painted,
galvanized sheet metal shield can be pushed into the ground to form a
semicircle concealing a bulb and holder to provide silhouette-, shadow-,
graze-, or cross-lighting (Figure 9B). A light bulb and holder can be suspended
over a patio table or sitting area from a tree, arbor, or porch to provide down-
lighting (Figure 9C). A shield for this bulb could be a globe, cylinder, cone,
or other shape made from glass, metal, or wood. The electrical cord may be
intertwined with a small cable or decorative chain for support. A light bulb
or series of bulbs in a channel under a bench can help provide light to a sitting
area or walk (Figure 9D). A perforated shield can create interesting light pat-
terns suited for some low-light areas (Figure 9E).
Installation Considerations for a Low Voltage
The central core of a low voltage lighting system is the transformer. Trans-
formers reduce a 110-volt house current line to 12 volts and should be se-
lected based on the number of fixtures on the system. The example plan in
Figure 7 calls for 19 fixtures requiring a total of 1260 watts. Therefore the
transformer for this system should have a minimum capacity of 1500 watts,
allowing for modest expansion. Overloading transformers may cause them
to burn out or result in dimmer lights. A fused transformer should be selected
or a fuse or circuit breaker would be required between the electrical service
line and the transformer (Figure 10).
The transformer is connected to the house electrical line and the lights are
attached to the transformer (Figure 10). A time clock or other control device
can be installed either before or after the transformer (110 or 12 volts) to con-
trol the lighting schedule. A controller on the input side of the transformer
(110-volt side) would result in longer transformer life because it would re-
ceive current only when landscape lighting is in use. Timers on the output
side of the transformer would allow different lines of lights set in series to be
controlled independently. Lights for the entrance walkway might be con-
trolled automatically by a time clock and the lights around the patio could be
Use weather-proof wire that. is specifically approved for ground burial.
Wires, switches, sockets, fixtures, or other materials should carry an Un-
derwriters Laboratory (UL) seal of approval. Wire should be insulated and
range in size from 12 to 14 gauge. Quick-connect electrical connectors can
be used to attach fixtures to wiring. Allow about 12 inches (30 cm) of slack
wire around each light fixture for any adjustment needed later. For example,
a plant may be allowed to grow larger than anticipated and a fixture may have
to be repositioned to be effective. Wiring for low voltage systems may be
placed on the ground surface under or behind plants, or buried. The deeper
the wire is buried the less likely it will be cut by garden tools such as edgers,
cultivators, lawn mowers, or shovels. Burying wire adjacent to walks or the
house foundation reduces the risk of cutting the wire. To bury wire in a turf
area, insert a shovel or spade in the sod at a 450 angle to a depth of 6 to 10
inches and pry back the sod. Place the wire on the exposed soil and press the
sod back in place (Figure 11).
Lighting fixtures in trees can be hung by a chain from a branch or secured
tightly. Fixtures anchored to a branch may be attached with a bolt into the
branch, but this attachment must be inspected annually and loosened if nec-
essary to prevent the tree from growing around the attachment point. Such
a bolt should not weaken appreciably the structural strength or the health of
a large branch. The wire may be serpentined down the branch and trunk and
an occasional staple to secure the wire to the tree may be necessary.
Avoid placing lighting fixtures above ground level in turfgrass areas.
Mowing around fixtures and wires above ground is neither efficient use of
time nor safe.
Landscape Lighting Costs
Cost of installation and operation of a landscape lighting systems should
be estimated before equipment is purchased. Low voltage systems are safer
and require less strenuous wiring than i 10-volt systems. Low voltage bulbs
generally last longer than 110-volt bulbs but have a higher purchase price.
Material and equipment required to install the lighting system in Figure 7 are
presented in Table 1. Retail prices in 1983 were used for all equipment and
for estimates of installation costs.
Operating costs obviously depend upon how much the system is used.
Operating costs have been calculated for the example system based on the
fact that circuit numbers 1 and 2 will be turned on automatically from 8:00
pm to 11:00 pm 7 months of the year and from 6:30 pm to 10:00 pm for 5
months. Circuits 3. 4. and 5 will be controlled manually and operated ap-
proximately 48,48. and 24 hours per month, respectively. Lights mounted on
the house are 110 volts and manually operated. They are estimated to be on
32 hours per month. Based on these assumptions, the system would use ap-
proximately 1000 kilowatt hours of electricity per month. The annual cost
would be $80 if the rate were SO.08 per kilowatt hour.
Proper design and installation of landscape lighting can provide security
and safety to the functional areas of the landscape and extend the use of the
landscape into the evening hours. The plan need not be elaborate to add sig-
nificantly to the beauty and safety of a landscape.
Table I. Estimated retail cost of materials and equipment required for the sample
lighting system in Figure 7.
Item Quantity cost ($)
Mushroom down-lighting fixtures 6 120.00
Shielded up-lighting fixtures 6 90.(X)
Shielded down-lighting fixtures 6 65.00
Transformer 1 120.00
Time-clock controller I 20.00
14-gauge wire (single wire) 800 feet 45.00
Total estimated cost 460.00
*Based on retail prices in 1983.
This public document was promulgated at a cost of $2922.95, or 50.4 cents
per copy, to provide information on lighting for landscapes. 12-5.8M-84
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