Progress Report Series No. 81
March 1961
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RAYMOND L. SELF and HENRY P. ORR'
A NEW TYPE plastic greenhouse suited to almost any space
or ground contour can now be built by nurserymen and hob-
byists.
Advantages of this house are economy of construction, sim-
plicity of design, availability of constrnction materials, and serv-
iceability as compared with more expensive houses.
Cost of all materials (retail prices) for this new type con-
struction is 25%12 cents per square foot for a i2x54-foot green-
house. For one 18x,36 feet, the square foot cost is 35 cents.
Expense for blade-equippecd tractor and operator for leveling
site and labor for erecting the greenhouse would be in addi-
tion to the cost of needed materials. (See material list, page 4. )
Curved t'pe greenhouses have bTen available several years.
However, the type of structure described here differs in that
reinforcing wire mesh is the only support needed for 12-foot
width houses. Only one lengthwise center support is needed
for houses 1:3 to 20 feet swide.
The house is built in sections of reinforcing wire cut to
measured lengths. Ends of the wire sections are anchored to
a rigid foundation extending along each side of the Iouse.
The frame ends of the house, including 
doors, are wood,
and shaped to wire curvature. After fastening the wire sections
togethier and covering house with plastic shade cloth and poly-
ethylene film, the frame ends are built in place.
Adequate ventilation on warm days can he obtained by
opening doors at both ends. The test greenhouses with one
coat of the film pro vided about a 10 warnir temperature than
outside. Readings on I)ecember 2, 1960 were as follows:
Hig1h Lore
\Veather station, outside temperature 670 23'
Plastic greenhouse, inside temperature 78' 32
Inner liners reduce the need for supplemental heat (elec-
tric or gas). With 2 mil. inner liner, one of the greenhouses
1 Plant pathologist in charge of Ornamental I orticulture
Field Station, Mobile, Ala.; and associate horticulturist.
was 17' warmer inside (low) than outside temperature. Janu-
ary 4, 1961, readings were as follows:
Weather station, outside temperaure
Plastic greenhouse, (2 coats) inside
temperature
High Low
58.50 260
63.00 430
In case of extremely high inside temperature, it will be
necessary to provide exhaust-fan ventilation.
Building details reported herein were developed at this
Field Station. Trials were conducted during 1960 to develop
simple methods for erecting low-cost greenhouses.
STEPS IN CONSTRUCTION
Determining Size
Decide on the size of greenhouse to meet your needs. Keep
in mind that the widths of the wire-plastic type houses range
from 12 to 20 feet. The house length must be in multiples of
6 feet (width in which the reinforcing wire comes).
If you choose to build a 12-foot width greenhouse, divide
the ground area into two 4 z-foot beds separated by a 3-foot
center passageway. In the case of an 18-foot width, divide
into two outer beds and a center bed of 4 feet each, separated
by two 3-foot walks. If you prefer use raised benches in place
of ground beds.
Site Selection
Carefully select the site for your greenhouse. Commercial
greenhouses should be in open areas with full exposure 
to the
sun. No obstructions should be close enough to cast shadows.
Locate your greenhouse so that it is 
accessible to electricity,
water, trucks, and tractors. A natural gas supply near the house
is desirable.
AUBURN UNIVERSITY E. V. Smith, Director
Auburn, Alabama
Agricultural Experiment Station
Select an area that is well drained or one that can be graded
and drained at minimum expense. The same conditions should
govern the location of hobby greenhouses as far as possible.
Site Preparation
Site preparation consists of leveling the area, filling where
necessary, and providing drainage ditches for runoff water to
prevent flooding greenhouse. (See Diagram A, inside spread.)
Sterilize the soil to eliminate weeds, nematodes, insects, and
disease-producing organisms. For this use such soil fumigants
as methyl bromide, mylone, or vapam, following directions of
the manufacturers. Also incorporate an insecticide into the
soil to give long lasting protection against grubs, ants, milipedes,
centipedes, and similar soil insects.
Suggested materials and rates of 10 per cent granular in-
secticides per 100 square feet of area, worked thoroughly into
the top 3 to 4 inches of soil, are: dieldrin, 1 ounce; heptachlor,
1 ounce; or chlordane, 3 ounces. Broadcast by hand or with a
seeder. Or spray comparable rates of liquid or wettable pow-
der, applying with a sprayer or a hose-on applicator.
If you choose to use ground beds, apply lime, phosphate,
and other fertilizer materials according to soil analysis. Thor-
oughly work these fertilizer materials plus peat moss into the
bed soils before you begin house construction.
Foundation
After site preparation you are ready to locate the four cor-
ners of the greenhouse foundation.
Caution: Take particular care in locating the corners, which
must be at right angles. Corners incorrectly located will lead
to later construction troubles.
Laying Out 18x36-Foot House. Cut six stakes 18 inches
long from 2x2-inch stock, sharpening one end of each stake. Use
four as corner stakes and two as alignment stakes midway 
along
sides of foundation. Measurements between four corner stakes
should be made at the inside corners.
A simple but accurate way to establish 900 corners is the
diagonal measurement method. In the case of the 18x36-foot
house, the two diagonals must be 40 feet, 3 inches.
Begin by driving two corner stakes exactly 18 feet apart
at one end of your prepared site. Next measure 36 feet at a
right angle from inside corner of second stake. The point at
which the 40-foot 3-inch diagonal and 36-foot measurements
meet is the exact position of inside corner of third stake. Work-
ing from your first stake, follow the same procedure for correct
location of fourth stake. When between stake measurements
are exactly 18 feet (width), 36 feet (length), and 40 feet 3
inches (diagonals), your foundation is square.
Drive stakes about I foot into ground. Use heavy twine
or builder's chalk line for foundation lines. Wrap twine so
that the stakes are on outside of chalk lines. Set alignment
stakes outside but flush with twine and mid-point at sides of
36-foot foundation lines.
In the case of a house 12 feet wide and 54 feet long, the dia-
gonal measurement is 55 feet, 4 inches.
Types of Foundation. The simplest is a double board foun-
dation, set on edge at ground level, extending full length of
the house. In the case of a house 36 feet long, you will need
six 1x6-inch pressure-treated, 12-foot boards for each side.
Beginning 3 inches in from each corner stake, put the three,
squared-end, inner boards flush against the twine foundation
line, each butting to the next. (Overall length, 351/2 feet al-
lows 3-inch space at each end for adjoining curved frames.)
Anchor these inner boards to the ground with 1x4-inch stakes
2 to 22 feet long placed 6 feet apart beginning at each end of
foundation. Drive stakes part way into ground and then level
the three boards with a carpenter's level, making any necessary
adjustments. It is extremely important that they are level end
to end. Then finish driving in the stakes flush with top of
boards and nail.
Repeat this same procedure for the other side. Then level
(crosswise) the staked, inner boards at several points along
sides. This may be done by resting carpenter's level on edge
of two 1x4-inch straight boards (each 12 feet long, carefully
lapped 4 feet and nailed) and raising or lowering the staked
foundation boards as necessary.
Do not install the outside foundation boards until the rein-
forcing wire has been put in place and stapled to the outside
surface of the inner boards.
Raised foundations require more materials, but offer you
the advantage of more headroom and air space. Concrete block
foundations are substantial, but are not recommended unless
you intend to equip your greenhouse with raised benches.
Center Support
You will not need a center support for a 12-foot width house.
Wider houses, however, must have support at center lengthwise
of structure. An economical method is to make your center
support an overhead watering system.
Example, 18x36-Foot House. Begin by setting a 4x4-inch,
10-foot treated post on exact center at each end of 
house, inside,
flush and square with chalk line. Set post 3 feet in ground
(7 feet above ground) and embed in concrete. Use carpenter's
level for plumbing post; brace in position until concrete sets.
Buy four 9-foot pieces and two 41/-foot lengths of 1 -inch
galvanized pipe with all ends threaded. Make up two sections
of 18 feet each, connecting with 1 x1 x -inch T's (outlets
for sprinklers). Cap one end of one section and screw a
1 x3/-inch bell reducer on one end of other section. Con-
nect threaded open ends of the two sections with a 1/x1 2xl
T. Lift the completed overhead waterline (36+ feet long)
in place on top of the two end posts, center, and temporarily
nail in place. The bell reducer should extend just beyond post.
Use the two 4 -foot lenghs of 1/-inch pipe to support
your overhead line at mid-point between the end posts. Cut
a 7-foot piece of scrap lumber to support the waterline until
the center post is completed.
Connect the two 4 -foot pieces with a 1 x1 x/-inch T
(outlet for hose spigot), and cap the ground end.
Dig a hole 2 -feet deep immediately under the center T-
joint of your water supply line. Place the completed pipe sup-
port in hole and then screw into the center T. Partially fill
hole with concrete; after setting, complete filling hole with
dirt. Then screw 4-inch nipple into 1 x1 x -inch T and
attach 3-inch hose spigot.
To complete inside portion of watering system, screw the
two 3x8-inch nipples into the 1xl% x/4-inch T's and at-
tach sprinklers.
The outside plumbing extending down from bell reducer at
end of house includes: galvanized pipe, union, globe valve
with soft washer, two 6-inch nipples, and hose spigot, all of -
inch size.
Cut and thread two 2-foot lengths of pipe and one piece
3 feet long. Screw one 2-foot length into the -inch opening
of bell reducer.
Next assemble the other 2-foot long pipe, globe valve, 6-
inch nipple, T, and 3-foot pipe in that order. Screw on
a -inch elbow at open end of the 3-foot pipe. This is for
connection with your water supply line below ground. When
completed attach your assembly to the 2-foot pipe extending
down from reducer, using a union to close the joint. The com-
pleted outside plumbing should be plumb with the wood cen-
ter post, and extend into ground about 10 inches. (See Dia-
gram B, inside spread.)
[21
Cutting Wire and Attachment
The most satisfactory wire at this Field Station is 6 feet
wide, with 170 feet in a roll weighing 540 pounds. The mesh
is 4x8-inch with vertical wires (4 gauge) 4 inches apart and hori-
zontal wires (9 gauge) 8 inches.
2
For a 12-foot width house, cut an 18-foot length. This
length gives a good arc with a center height of 6 feet and a
5-foot height at 20 inches from foundation.
Cut 27-foot lengths for a house 18 feet wide and 7-foot
height at center. This length gives a height of 5 feet at about
3 feet in from foundation.
Example, 18x36-Foot House. Use two men to cut wire sec-
tions. One stands on the loose end while the other cuts with
a set of bolt cutters.
Unroll wire and cut six lengths of 27 feet each. The roll
comes with 2-inch open ends of horiznotal wires at one end
and 1/2-inch overhang at other end. These are for interlocking
the sections.
Beginning at one end of greenhouse, pass wire section over
center support and spread ends to outside bf foundation boards.
Extend wire 3 inches beyond each end of inner foundation.
Force wire into ground against outside face of foundation
boards. Staple to board at weld joints at 3-foot intervals after
wire is evenly in place at all points. For added stiffness, at-
tach reinforcing wire at intervals to the center support (water-
line) with galvanized wire.
Put the next section in place, making certain that the out-
side vertical wire of the two sections adjoin alternately through-
out section lengths. After stapling to outside of foundation
board, loop the 2-inch ends around the two adjoining vertical
wires. A 4-inch pipe 4 inches long is a handy tool for bend-
ing and joining. Repeat procedure with other four sections.
When completed, add the outside foundation boards. Ex-
tend boards 3 inches beyond inner boards at ends of house.
After cutting and fitting, nail the outer boards against the
stapled reinforcing wire into the inner foundation boards. (See
Diagram C, inside spread.)
Shade Material
Plastic greenhouses become hot on sunny days even in win-
ter if not shaded. The most satisfactory shade is luminite saran
shade cloth, a long-lasting plastic mesh. Use a mesh giving
50 to 64 per cent shade. This material costs about 30 to 35
cents per square yard (9 square feet). You can order this ma-
terial to exact size to fit your greenhouse.
Before putting on the covering, be sure that all wire ends
are turned in to avoid damage to the plastic material. Begin-
ning at ground line of one foundation, unroll the shade cloth
over the curved reinforcing wire and down to ground line of
opposite foundation. Allow a 3-inch overhang beyond wire
at ends of house. Smooth the shade cloth by gently pulling
both crosswise and lengthwise. Do not stretch.
Plastic Cover
Polyethylene film, 4 mail. thickness, has proved satisfactory.
You can buy this material in sheets wide enough to cover the
house. It is also available in narrow widths. If .used, he sure
to lap the joints 6 to 12 inches. The 4 mail. plastic costs about
1 / to 2 cents per square foot. It normally lasts about 6
months; better, more expensive grades last considerably longer.
2 This grade of wire was developed by the Truscon Division,
Republic Steel Corp., and is marketed under the trade name,
"Truscon Winter Garden Fabric."
Use the same method for putting on the plastic cover as
that used in applying the shade cloth. Allow the same 3-inch
overhang at house ends. Pull the plastic gently both ways to
avoid wrinkles, but do not stretch (shrinks in cold weather).
Fasten both shade cloth and plastic covering on top of the
outside foundation boards using strips of lath and small nails.
By putting on the shade cloth first, you can remove the
polyethylene cover after danger from cold damage is passed.
End Construction
The best method for constructing the end frames for 18x36-
foot house is to build them in place. Your first step is to build
for each end four laminated sections, bowed to fit approximate-
ly the curvature of house. These formed pieces may have to
be built in a woodworking shop if you do not have the neces-
sary wood floor space and tools.
Bowed Laminates. Use three pieces of knot-free stock, 1x3
inches 14 feet long (dressed size %x2% inches) for each of the
eight laminated, bowed frames.
Lay out full size pattern on wood floor. (See Diagram D,
inside spread.) Draw a 9-foot base line (AC) and a 7-foot
vertical line (BC). Make a string compass of heavy twine,
tying one end to chalk and other end to a nail. The chalk and
nail must be 9 feet apart.
From point "A" scribe an arc down from point "C," using
the 9-foot radius; from point "B" scribe another 9-foot radius
arc. At the point where the two arcs cross, "D," scribe the arc
from "A" to "B," again using the 9-foot radius.
Anchor with heavy nails 2x4-inch blocks on outside of curve
AB, using as many blocks as needed to pull the three-ply lam-
inate into place. There must be blocks at points "A" and "B."
Next place three strips on edge, centered between "A" and
"B." Using furniture clamps and working from the middle
three blocks, begin to tighten. Make necessary adjustment of
clamps' jaw openings as you bring laminate fully into place. If
needed, use "C" clamps for the other blocks.
Next nail the bowed strips at several places between blocks
from outside to inner strip. Use a sledge to "buck" when nail-
ing and bradding.
Use a 1x4-inch piece of scrap lumber 14 feet long nailed
to ends of laminate to hold temporarily. Before removing from
form, mark and label the laminate at points "A" and "B." Fol-
low the same procedure for next three laminated bows.
Draw a line full length along inside curve of the fourth
laminate before taking out of form. This is your new working
line (8-foot, 10-inch radius) to which you bend the four lam-
inates for the large doors.
Move blocks to the new inner curve line and anchor them
to floor. Then bend the laminating stock (three pieces) into
position and nail together just as you did in forming the first
four bowed pieces. Mark and label points "AA" and "BB,"
and nail scrap stock to hold bows temporarily in position. Re-
peat procedure for bending other three laminates for doors.
Supporting End Frames. Use the first four "AB" laminates
for supporting reinforcing wire at ends of house. Remove the
1x4 holding strip. Saw off extra length at point "A" and
position against extended end of outside foundation board to
"try for size." The point "B" end of laminate is to butt to the
1 /-inch pipe centered on the 4x4 post. With removal of hold-
ing strip, the laminate will lose some of its bow. Therefore,
spring it to conform to curvature of reinforcing wire and mark
the point at which laminate will butt the center pipe. Remove
laminate and saw off the extra length.
Butting end "B" to center pipe, lag screw at an angle to
top of post. For details of anchoring end "B" (see Diagram
E, inside spread). Next spring end "A" into position at extended
end of outer foundation board. Repeat this same procedure
for other AB bowed frames for supporting wire.
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When completed, tie each pair of bowed frames together
with 2x8-inch metal straps, %s-inch thick, centered across 1 -
inch pipe; nail or screw to butting ends of the frames as shown
in Diagram E. Next fold shade cloth and plastic cover around
and under bowed frames and fasten with stapling gun.
Door Frames. Fit laminate AA-BB for top of door under
supporting bow, cutting to correct length (from side of post
to point "A"). Use shims, or thin tapered wedges, between the
two bowed laminates while building the large door. Use 2x2-
inch rough-sawed stock for framing. With the laminate fitted,
in place, and shimmed, cut the bottom piece for door to fit
between "AA" and side of center post. Saw the upright at
post-side of door to fit between laminate and bottom 2x2. Space
the second and third uprights to accommodate an inner door
(2 feet, 8 inches wide and 6 feet high) 1 foot in from center
post. Cut a 32-inch piece for top of inner door opening, and
nail between the two uprights. Center the fourth upright in
remaining space at bottom 2x2 and cut to fit between bottom
piece and laminate. Toenail uprights at bottom 2x2 and center
nail all other joints. Next build inner door frame to fit opening.
This door will permit entrance to house without excessive loss
of heat during cold weather.
To strengthen joints, use gussets (triangular braces) cut
from scrap Y4-inch weatherproof plywood; nail them to inside
face of door frames.
Build the other three large doors in place, following the
same procedure, except omitting the small passage door. In-
stead, equally space the uprights along the bottom 2x2's.
To swing the large doors out to center line of house, screw
or nail hinges to center post and adjoining uprights. Provide
all doors with hasps or latches. Also install hinges for inner
door. (See Diagram F, inside spread.)
Cover all doors with shade cloth and plastic film, fastening
to framing with stapling gun. Allow about 3 inches overhang
of covering materials for folding around curve of door. Using
a sharp knife, cut along top and edge of inner door, leaving
overlap at bottom.
To reduce draft through the house during cold weather, nail
door stops about 4 inches wide along inside of laminates sup-
porting the reinforcing wire. Cut the "stops" to curvature,
using Y4-inch plywood scrap, repeat for inner door if needed.
End Frame, 12-Foot House. Since a 12-foot width house
requires no center support; end frame construcion is simpler
than that for wider houses. Build two ends according to fram-
ing details, using scrap lumber. (See Diagram G.)
The framing for each end consists of a 12-foot baseboard
(pressure treated) nailed to ends of foundation boards at side;
two vertical pieces for door opening to which reinforcing wire
is stapled at top; a crosspiece at door height; and two diagonal
braces from ends of baseboard to top of vertical supports. Saw
pieces to measured lengths and nail in place. Next build door
to fit opening, including a panel hinged at bottom (open out-
ward) for ventilating house. Cut a piece of shade cloth to
cover opening for hinged panel, and staple to inside of door
frame to keep out insects while panel is open. Also, cover out-
side of panel with plastic film. Next cover remainder of end
with shade cloth and plastic, stapling to the framing. Allow
an overlap at top for joining covering materials of ends with
that of the top, using a hand stapler. Cut out the door opening,
and cover lower door panel with shade cloth and plastic film.
Inner Liner
To reduce need for heat, an inner liner of 2 mil. polyethy-
lene film may be applied to inside of greenhouse. This liner
provides air space between outer and inner plastic covering
that acts as insulation. The inner plastic supported by wires
extends from end to end of house.
Materials required for installation of inner liner in an 18-
foot width house are: one 300-foot roll of 16 or 20-gauge wire,
and 75 feet of 2 mil. plastic 16 feet wide.
Stretch one length of the plastic lengthwise and anchor from
center of house at ends, using a P-9 staple gun. Then attach
one end of wire to end of house adjacent to water pipe, stretch
wire, and anchor at other end of house. Repeat this with three
more wires-evenly spaced between first wire and foundation
board. Four wires per side provide about 6 inches of air space
at midpoint between each pair of wires.
Next clamp supporting wires and plastic liner to horizontal
wires of reinforcing mesh. Use "hognose" type clamps, applying
them with a P-7 Bostick gun. Space clamps 2 feet apart along
each wire. Staple loose end of liner to inside of foundation
boards. Repeat procedure at other side.
MATERIAL LIST and RETAIL COSTS
Materials Required
Galvanized concrete pipe reinforcing
wire, 4"x8" m esh---------------------
Plastic, polyethylene film, 4 mil
Saran plastic shade cloth, mesh to
give 50 to 64% shade ------- ------------
Wood foundation, 12'x54' house ...........
18 pc. 1"x6"x12', rough, pressure treated
4 pc. 1"x4"x12', rough, pressure treated
Wood foundation, 18'x36' house ------
12 pc. 1"x6"x12', rough, pressure treated
3 pe. 1"x6"xl2', rough, pressure treated
Wood framing for ends, including hinges
Costs
12'x54' 18'x36'
house house
$82.50 $82.50
15.00 15.00
42.00
19.22
I
Center support, fittings for 18'x36' house
2 4"x4"xlO' posts, pressure treated at $1
4 "x4" lag screws at 2 2c --- ----
1 pc. " gal. pipe, 7' at 18c per foot .....
4 9' pc. and 2, 41/2' pc. 1" gal. 
pipe
6.00
64.72
.95 -.
42.00
13.02
25.00
$177.52
$ 3.90
.10
1.26
all ends threaded ----------------- ------ 22.05
1 1 "x1 2" -T ... ... .. ... ... .. .. . ... .. 1.10
3 1 "x1 "x %" T's at $1.45 ------------------------ 
4.35
1 %"x3"x"T .33
1 "x4" nipple at 27c --- .27
2 3"x6" nipples at 27c .54
2 /"x8" nipples at 27 .54
1 3" union 
.59
2 1 " caps at 55c ..- -- 1.10
1 ," elbow -- 
.28
1 11/2"x"3/4 bell reducer 
.79
1 %" globe valve with soft disc 1.98
2 " hose spigots at 99c .- --------------------- 
1.98
2 No. 20-U, upside down, sprinklers at $4 -- 8.00
$ 49.16
TOTAL, sales tax not included--------- $164.72 $226.68
Cost per square foot.. 25.4c 35.Oc
The foregoing list for the 18x36-foot house does not include
cost of materials for inner liner. Add $8.50 for these items.
Note: The information given in this report regarding ma-
terials is supplied with the understanding that no discrimination
is intended and no endorsement by this Agricultural Experiment
Station is implied.
ACKNOWLEDGMENT
The reinforcing wire was furnished by the Truscon Division,
Republic Steel Corporation, Birmingham, Ala. The authors
also acknowledge the valued assistance in this project of D. G.
Belshaw, district sales manager, and Frank Shy, agricultural
extension representative of the above company; and Alvin R.
Lowe, Alabama Vocational and Technical School, Mobile, Ala.
[4]
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