Most greenhouses are erected to produce plants
during the off-season;therefore, they must provide a desirable plant environment. Correct location and orientation of
the house are of paramount importance in providing ideal
environmental conditions. Since location can also influence
the heating cost, labor utilization. and diseasefactors, economic successmay also depend on the site selection.
R e c o m m e n d a t i o n sf o r l o c a t i n g a n d o r i e n t a t i n gy o u r
g r e e n h o u s ea r e g i v e n i n t h i s p u b l i c a t i o n . T h e f o l l o w i n g
specifications are the ideal ones; however, some builders
may not be able to follow each suggestiongiven, depending
o n i n d i v i d u a l l i m i t a t i o n s o f t h e i r h o u s e s .F o r e x a m p l e ,
houses used for display and sales purposes are often connected to existing buildings; therefore, they may have to
sacrifice some of those factors described for productiont y p e g r e e n h o u s e s .B e n c h c u l t u r e o r s i m i l a r p r o d u c t i o n
practices may also justify deviation from some of the
standard requiremenrs.To provide optimum plant response
and teaching effectiveness.however, the authors believe
recommendations should be followed as nearlv as
p o s s i b l ei n b u i l d i n g a l l h o u s e su s e d f o r e d u c a tional purposes.
LOCATION OF THE
GREENHOUSE
Sunlight
provides
Sunlight
energy for plant growth, and
i s g e n e r a l l yt h e l i m i t i n g f a c t o r
. hen planin greenhousesW
ning the construction, give
p r i m a r y c o n s i d e r a t i o nt o o b taining maximum sunlight
exposure
during those
"short" days of mid-ra,inter
when the sun is lowest in the
Issued in furtherance of Cooperative Extension work,
Chules E. Barnhart, Diretor
of Cooperative Extesion
sky. Maximum sun altitude (angleof sun above earth's
h o r i z o n ) o c c u r sa t n o o n a n d v a r i e sf r o m a h i g h o n J u n e 2 1
to a low on December 21. Solar altitudes for selectedlatiin deoreesn,:rth and south from
tudes (distance measurec.l
the equator) and times of day are given in Table 1. The
l a t i t u d e o l 4 2 o w o u l d c o r r e s p o n dt o D e t r o i t , M i c h i g a n ;3 8 o
t o L e x i n g t o n . K e n t u c k y , 3 4 o t o L i t t l e B o c k , A r k a n s a s a; n d
3 0 o t o N e w O r l e a n s .L o u i s i a n a .A t s o l a r n o o n , t h e s u n i s
l o c a t e dd u e s o u t h . T h i s m e a n st h a t t h e b u i l d i n gs i t e s h o u l d
preferably have an open southern exposure. lf the land
s l o p e s ,i t s h o u l d i d e a l l ys l o p et o t h e s o u t h .
D o n o t b u i l d n e a r l a r g et r e e s ,b u i l d i n g s ,o r o t h e r o b s t r u c t i o n sw h i c h w i l l s h a d et h e b u i l d i n g . F i g u r e 1 g i v e st h e
ratio of shadow length and height obstructions for selected
solar altitudes. To determine how far away an obstruction
must be to prevent a shadow on the greenhouse,multiply
these ratios by the obstruction height.As a generalrule, the
greenhouse should be located at least 2.5 times the height
of the object away from it, in either the east, west, or south
direction. Even objects this tall will cast lonq shadows
i n t h e e a r l y m o r n i n gw h e n t h e s u n i s p a r t i c u l a r ly low in the sky.
Soil
When plants are to be
grown in the soil covered by
t h e g r e e n h o u s e s, e l e c t a s i t e
w h e r e a d e e p ,g o o d d r a i n i n g ,
f e r t i l e s o i l i s a v a i l a b l e .A
sandy loam or silt loam type
soil is preferred.Avoid top
soil below which a tight
h a r d p a n i s p r e s e n t .A l t h o u g h
organic matter and artificial
types of conditioners can be
a d d e d , p r o b l e m sa r e r e d u c e d
i f a s i t e w i t h q o o d n a t u r a ls o i l
acts of May 8 and June 30, 1914, in cooperation with the U.S. Department
College oI Agriculture,
Service, University
of Kentucky
of Agriculture.
AEN-32
Table 1.-Solar Altitudes for Selected Latitudes and Time{
SolarAltitudesat Specif
ied
(Anglep of
Times,Degrees
F i g u r e1 )
8 : 0 0a . m .
and
Date
Latitude
420
Dec21
Mar 21 &
Sept 21
June21
3go
40
lgo
250
4Q
59
48
72
220
2go
43
60
52
76
260
330
37
46
62
56
80
110
2go
370
26
37
49
60
84
23
37
go
z1
Dec 21
Mar 21 &
Sept 21
J u n e2 1
12:OQ
(noon)
2 : 0 0p . m .
70
Dec 21
Mar 21 &
Sept 21
J u n e2 1
3oo
and
4 : 0 0p . m .
22
37
Dec 21
Mar 21 &
Sept 21
June21
uo
1 0 : 0 0a . m .
* F r o m A . S . H . R . A . EG
. u i d ea n d O a t a B o o k , N e w Y o r k , 1 9 6 5
lf you question the degreeof danger,grow selectedplants
i n s a m p l e so f t h e s o i l t o d e t e r m i n ei f a n y d e t e c t a b l ei n j u r y
o c c u r s . N o x i o u s w e e d s e e d sc a n a l s o b e a p r o b l e m , b u t
g e n e r a l l yp r o p e r s t e r i l i z a t i o nm e t h o d s w i l l k i l l m o s t w e e d
seeds.
W h e r e a g o o d s o i l i s n o t a v a i l a b l ef o r t h e l o c a t i o no f
t h e g r e e n h o u s ec, o n s i d e rc u l t u r a l t e c h n i q u e su s i n ga r t i f i c i a l
m e d i as u c h a s o e a t a n d v e r m i c u l i t e .
Drainage
S e l e c t a s i t e t h a t i s l e v e la n d w e l l d r a i n e dt o r e d u c e
p r o b l e m sw i t h s a l t b u i l d - u pa n d i n s u f f i c i e n ts o i l a e r a t i o n .A
h i g h w a t e r t a b l e m a y r e s u l t i n s a t u r a t i o no f t h e s o i l a n d
prohibit effective use of the greenhouse.Ground water
which flows into the house may carry soil diseases.lf necess a r y , t i l e d r a i n t h e a r e a e n c l o s e db y t h e g r e e n h o u s eT. i l e
lines within the greenhousecan also be used for steam
s t e r i l i z a t i o ni f p r o p e r l y p l a c e di n t h e s o i l .
G r o u n d b e d s s h o u l d b e n e a r l y l e v e l .l f t h e y s l o p e i n
any direction, water will tend to concentrate in the low
areas, accentuating any problems of poor drainage.Slopes
w i t h i n t h e g r e e n h o u s ea l s o a l l o w h o t a i r t o r i s ea n d c o l d a i r
to settle, creating added problems for the environmental
system to overcome. A greenhouse in a low, damp area
c o u l d b e s u b j e c tt o h i g h e r h u m i d i t i e sa n d d a m p n e s sw h i c h
etc.
accentuateleaf mold, diseases,
ANGLEP
to
20
30
40
R A T I OL / H
5.67
Sheltered Area
2,75
|.73
t .t 9
o.84
60
70
o.58
o.36
HEIGHT
OBSTRUCTION( H }
i
S H A D O W L E N G T H( L )
---------l
I
Although obtaining maximum sunlightshould have
f i r s t c o n s i d e r a t i o n ,p l a c i n g t h e g r e e n h o u s ei n a s h e l t e r e d
. o r e x a m p l e ,a
a r e a w i l l r e d u c e w i n d - i n d u c e dh e a t l o s s e s F
m a y m a t e r i a l l yr e d u c e
w i n d b a r r i e rn o r t h o f t h e g r e e n h o u s e
h e a t i n g c o s t s ;y e t i t w o u l d h a v e l i t t l e e f f e c t o n t h e l i g h t
received. Trees are helpful in preventing winter heat loss,
but deciduous treeswhich lose their leavesin the winter are
n o t e f f e c t i v ew h e n t h e h e a t l o s sp o t e n t i a li s g r e a t e s t .
In areas of heavv winter snowfall where snowdrifts
occur, wind and srrow breaks need to be 100 feet or more
away from the greenhouse to reduce major drifts.
]
Figure 1 Ratio of shadowlengthand obstructionheightfor selected solaraltitudes.
is selected. Grading often produces uneven soil conditions
w i t h i n t h e g r e e n h o u s eC. a r e f u ls o i l a n a l y s i sa n d p r e p a r a t i o n
are necessaryif even plant growth is to be achieved.Before
a n y o r g a n i c m a t t e r o r a d d i t i v e sa r e m i x e d w i t h t h e s o i l ,
m a k e a c o m p l e t e s o i l a n a l y s i sa n d c a r e f u l l y f o l l o w t h e
resulting recommendations.
A v o i d a r e a s w h e r e c h e m i c a l r e s i d u e sw h i c h w o u l d
'
i n l u r e g r e e n h o u s ec r o p s m a y p e r s i s t , i n c l u d i n g p l a c e s
h e a v i l ys p r a y e dw i t h d a m a g i n gw e e d k i l l e r s a n d h e r b i c i d e s .
Utilities
A g r e e n h o u s er e q u i r e sa n u m b e r o f u t i l i t i e s .n o t a b l y
e l e c t r i c i t y ,w a t e r , a n d a n e n e r g ys o u r c ef o r h e a t .
Electricity: The electric servicefor ventilation alone
w i l l r e q u i r e a p p r o x i m a t e l y4 t o 6 k i l o w a t t s f o r a 1 1 4 - a c r e
r a n g e . F o r a s m a l l h o b b y - s i z e dh o u s e , c o n n e c t e dl o a d so f
u p t o I t o 2 k i l o w a t t sa r e n o t u n u s u a l .l f l i g h t sa r e u s e df o r
photoperiod control or supplemental ighting,the electric
l o a d w i l l i n c r e a s es i q n i fi c a n t l y . N o r m a l l y t h e e l e c t r i cp o w e r
c o m p a n i e s w i l l w i l l i n g l y s u p p l y t h e n e c e s s a r ys e r v i c e ;
however, the grower should attempt to anticipate his
intended electric usage and provide sufficient entrance
c a p a c i t yt o a l l o w f o r f u l l e l e c t r i cu t i l i z a t i o n .
z
AEN-32
W a t e r : A r e l i a b l es u p p l y o f c l e a nw a t e r i s m a n d a t o r y .
A w a t e r r e q u i r e m e n to f u p t o 1 / 3 g a l l o n p e r s q u a r ef o o t p e r
d a y m a y b e n e e d e d .D e p e n d i n gu p o n t h e s o i l t y p e , u p t o 1
gallon of water per square foot may be put on the soil at
o n e t i m e . W a t e r f r o m p o n d s h a s t h e d i s a d v a n t a go
ef b e i n g
cold during the winter. lf this water is used directly for
irrigation, plant roots may chill, causinga detrimental
effect. Pump water from such sourcesinto a large storage
tank within a heated portion of the greenhouseor headhouse so that its temperature will approach that of the
p l a n t s .A l s o , w i t h p o n d s , t h e p o s s i b i l i t yo f c h e m i c a lp o l l u t i o n e x i s t s u n l e s st h e s u r r o u n d i n gd r a i n a g ea r e ai s c a r e f u l l y
controlled.
Energy Source: The availability of an inexpensive
energy source is often one of the most important factors in
determining where to build a greenhouserange.Natural gas
is a widely preferred fuel becauseof its clean performance.
l o w m a i n t e n a n c ea
, n d r e l a t i v e l yl o w c o s t . N o t o n l y i s i t o n e
of the lower cost fuels, but gas heating equipment is genera l l y a m o n g t h e l e a s t e x p e n s i v ef o r i n i t i a l c o s t . a n n u a l
m a i n t e n a n c ea, n d o p e r a t i n gc o s t s .L P G a s ,f u e l o i l , a n d c o a l
are alternate sources of fuel and can be transported to
greenhouselocations that are not close to gas lines.
Electric energy is becoming more competitive in
many areas for greenhouseheating where the above fuels
a r e i n s h o r t s u p p l y o r r a p i d l y r i s i n g i n c o s t s . H o t - a i rr e s i s t ance heating units can be used in hobby or individual
houses. Central hot-water furnaces could be more suitable
for larger combined houses of 1/4 acre or more. Since
heating costs can be as much as two-thirds of the production cost for some crops,selecta location and energy source
c a r e f u l l yf o r f u t u r e a v a i l a b i l i t ya n d e c o n o m y .
Emergency Power
Standby emergency power equipment sized for
e l e c t r i c a ls u p p o r t o f h e a t i n ge q u i p m e n t ,a i r c i r c u l a t i o n ,a n d
minimum ventilation is vital when winter storms disrupt
l o c a l s e r v i c ef o r l o n g p e r i o d s( 2 h o u r s o r m o r e ) Alarm System
The consequencesof a heating system failure during
freezing temperaturescan be catastrophic.An alarm system
w h i c h i s i n d e p e n d e n to f t h e e l e c t r i c a sl e r v i c es h o u l d ,t h e r e f o r e , b e p r o v i d e d . P l a c e - t h e a l a r m b e l l i n a r e s i d e n c eo r
l o c a t i o nw h e r e p e o p l ea r e n o r m a l l y p r e s e n t .
Convenience
Locate the greenhousenear your place of residence,if
possible, or where a caretaker can be housed nearby. This
w i l l p r o v e c o n v e n i e n tf o r s e c u r i t y a n d w i l l f a c i l i t a t e c a r e
d u r i n g w e e k e n d so r h o l i d a y p e r i o d s . l f t h e v e n t i l a t i o na n d
w a t e r i n gs y s t e m sa r e n o t f u l l y a u t o m a t i c ,o p e r a t o rc a r ew i l l
a l s o b e m a n d a t o r y d u r i n g s u n n y p e r i o d s .S h o u l d a h e a t i n g
f a i l u r e o c c u r , c o r r e c t i v ea c t i o n m u s t b e p r o m p t .
O R I E N T A T I O NO F T H E G R E E N H O U S E
Light Availability and Shading Effects
O r i e n t a t i o n o f t h e g r e e n h o u s ef o r m a x i m u m l i g h t
. a n b e c ka n d
a v a i l a b i l i t yi s a l s oa n i m p o r t a n t c o n s i d e r a t i o nM
A l d r i c h ( " A n a l y t i c a l D e t e r m i n a t i o no f D i l e c t V i s i b l e S o l a r
E n e r g y T r a n s m i t t e db y R i g i d P l a s t i cG r e e n h o u s e s ,""T r a n s .
o f A S A E , 1 9 6 7 ) r e p o r t t h a t a n e a s t - w e s ot r i e n t a t i o r r( i . e . ,
t h e r i d g e o f t h e h o u s e r u n n i n ge a s t a n d w e s t ) i s p r e f e r a b l e
i n t h e w i n t e r f o r n o r t h e r n l o c a t i o n s( a b o v e4 0 o t o 4 5 " l a t i tude). At other times of the year for the northern regions
a n d a t a l l t i m e s f o r t h e s o u t h e r n r e g i o n s ,a n o r t h - s o u t h
o r i e n t a t i o n o f t h e r i d g e i s p r e f e r a b l e .S i n c e l i g h t i s m o s t
c r i t i c a l d u r i n g m i d - w i n t e r ,g r o w e r si n t h e n o r t h e r n l a t i t u d e s
( i . e . , 4 0 " N o r g r e a t e r )s h o u l d u s e t h e e a s t - w e sot r i e n t a t i o n
for single-width houses if possible.With east-westorientat i o n , h o w e v e r , a p r o b l e m i s e n c o u n t e r e dw i t h r i d g e a n d
f u r r o w h o u s e s .A d e f i n i t e s h a d o w l i n e d e v e l o p sw i t h i n t h e
housesdue to the north sloping roof sectionsand the gutter
between sectionsof the house.This shadow effect is usually
sufficient to result in reduced plant growth in the region of
the house affected. Depending upon the width of span, the
shadow area can be 10 percent or more of the house space.
Although shadows occur within north-south oriented ridge
and furrow houses, the shadows move acrossthe floor of
and noticeable reduction in
the house as the day progresses
g r o w t h i n o n e r e g i o n o f t h e g r e e n h o u s ei s n o t n o r m a l l y
apparent.
Environmental Equipment
V e n t i l a t i o n , c o o l i n g a n d h e a t i n g s y s t e m sa r e n o t i c e ably affected by the way the greenhouseis oriented and the
e q u i p m e n ti n s t a l l e d .
Ventilation: Ventilation air should not have to move
more than 12O to 150 feet across the house between
e n t r a n c e ' a n de x i t . D e s i g na n d i n s t a l lf a n v e n t i l a t i o ns y s t e m s
so that air moves with lin the direction of ) prevailingsumm e r w i n d s r a t h e r t h a n a g a i n s tt h e m . T h i s p r o c e d u r ew i l l
e l i m i n a t e o p p o s i n g a i r f o r c e s w h i c h d e c r e a s et h e a i r f l o w
rate by 10 percent or more. Usually,you should install
andfresh
e x h a u s tf a n s i n t h e l e - , w a r de n d o f t h e g r e e n h o u s e
a i r i n l e t s h u t t e r si n t h e w i n d w a r d e n d . H o w e v e r ,s o m e t i m e s
a s i d e w a l l f a n l o c a t i o n i n t h e l e e w a r ds i d e a n d f r e s h a i r
i n l e t so n e a c he n d a r e b e s tf o r c e r t a i nh o u s e s .
Cooling System: When pad coolinq is used. locate
p a d s o n t h e n o r t h r a r a l(le n d o r s i d e )o f t h e g r e e n h o u s e ( st o)
p r e v e n t s h a d i n g .F o r b e s t c o o l i n g e t f e c t i v e n e s sa,i r s h o u l d
4EN-32
not travelover 100 feet betweenpadsand the exhaustfans.
F o r l o n gh o u s e so, v e r1 0 0f e e t i n l e n g t hl,o c a t et h e b a n ko f
pads in a sidewallat the centerof the housewith fans in
e a c he n d . ( N O T E :A w a t e rs u p p l yo f a p p r o x i m a t e l1yt o 2
gallonsper minute per 100 squarefeet of padsis generally
required.Also. 100 squarefeet of pad areasper 1,200 to
floor areais typical.Obtain
1,500squarefeet of greenhouse
pad
coolingbeforemakinga
on
information
more detailed
purchase.)
decisionto
Heating System: The greenhouseheating system
should provide adequateheat supply and distribution
uniformity. Conthroughoutthe housefor environmental
sistent heat supply is especiallyimportant toward the
northwestportion of glasshousesor those with sizeable
and infiltration.
cold air leakage
Expansion
W h e n b u i l d i n g ,a l w a y s k e e p f u t u r e e x p a n s i o ni n
mind. Most successfulrangesare expandedseveraltimes
afterthe first houseor smallrangeareais constructed.
N
i-
{
I
wtND BREAKS -
I
#m %"
&ffiry
w!'
g.
I (I
S
CARETAKER
I
HOUSE- -,------+
..- jrnuc*
I
,J ACC€SS a
-| - - L - - r - l - - i - o p r t o N A L
SEPARATE
, 1 S T O R A GAE/ O R
SITE LAYOUT
Gradeand Fill
gradeand fill those
Prior to erectingthe greenhouse,
the site,establish
level
needed
to
are
changes
areaswhere
you
plan
to practicesoil
parking,
etc.
lf
roads,
drainage,
culture.rememberthat poor existingsoil must be removed
and replacedby 12 inchesor more of good topsoil.Grade
then replace
and fill the sub-soilmaterialto requirements,
tiling or
the top soil without compaction.Any subsurface
utility linescan be placedduringtheseoperations.
t-Ti
-1
ol
L.
I
el: i
Pt= I
!l: I
J--.i
Figure 2. Typical greenhouse range layout on a level but well
drained, southerly oxposed site.
SUMMARY
lmportantpointsto rememberare:
o
O r i e n ta n d l o c a t et h e h o u s ef o r m a x i m u ms u n , e r i d g es h o u l dr u n
l i g h t .I n s o u t h e r nl a t i t u d e st h
east-west.
andin northernlatitudes,
north-south.
o
Avoid placingthe housenearobiectseast,west,
or southwhich will shadethe house.
o
Placein an areashelteredfrom northerlyand
n o r t h - w e s t e rhl yi g hw i n d si f p o s s i b l e .
o
Locate on a deep good soil which is well
drainedand where surfacewater doesnot run
into the house.
o
Avoid slopingbedsor floors in the greenhouse.
Locate the greenhousenear adequateand
r e l i a b l es o u r c e so f u t i l i t i e s - e l e c t r i c i t yw, a t e r
and gas.
r
Providegood accessroads,parking,and turnaroundarea.
o
or supportingfacilitieson
Positionheadhouses
the north side.
o
Arrangeinitial constructionso that the range
can be expanded.
Transportationand Parking
When selectingthe site,try to locateneara good road
so that materialscan be convenientlymovedto and from
Sufficient room for turning and parking
the greenhouse.
of commercialsize,
vehiclesis desirablefor greenhouses
plants
are soldon the
flowers
and
especiallywhen bedding
premises.Allow 18 feet for head-inparking spacesand
26-30 feet clearancefor back-outand turning. Make any
curvesor turnswith 18-20foot insideradius.
Headhouses
Place headhouseson the north side of the greenhouse
to avoid shading a portion of the house.Attachment to the
greenhouseor a connecting passagewaymakes work, handling. and greenhouse operations more convenient but
complicates construction techniques to attach without
l e a k sa n d o t h e r m a i n t e n a n c ep r o b l e m s .P r o c e s s i nfga c i l i t i e s ,
cold storage rooms, and other such facilities should be
adequately incorporated into the ultimate layout.
providc reseirrch, trltrcltiotrirl inforrrrltiotr and
The College of Agricultrue is an Equal OpportuDit)' Orgrurization lrrthorizt'd to
sex or nirtion{l ()rigin.
other sctvices orrly to indivicluirls nDd institutions thilt functi(nt $'ithout regirrd to racc, color'
l s s u e 1d 1 7 4 ' 8 M
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