How to Build a Greenhouse

HOW TO BUILD A GREENHOUSE

METHOD 1[1]

·  ITEMS YOU WILL NEED

o  Universal Canopy, 10 x 20 ($180)

o  6 mil clear plastic. Roll size 20’ x 100’ ($40)

o  4 to 8 T- Posts ($3 each)

o  15 to 20 Squeeze Clips ($1-4 each)

o  18 Ratcheting Tie- Downs ($3 each)

o  1 Roll Duck Tape ($3)

o  3 Rolls Heavy Duty 3M Clear Tape ($5 each)

INSTRUCTIONS

·  Use 2-3 people to set up your frame, and as you insert each piece wrap the connection point with 2 or 3 rounds of Duck Tape. This will hold the pipe in place until the tape rots or you cut it off

·  Attach the Tie Downs. Stagger all 18 evenly over the top of the frame. This will add structural strength and keep the plastic from sagging and collapsing from rain, snow, and sleet. Make the straps tight, but don’t bare down and over tighten

·  Use at least 4 T-posts to anchor the 4 corners of the greenhouse. Place the T-post on the inside and drive at least 12” in the ground. Then wrap at least the top 24: with Duck Tape to secure and eliminate any sharp edges.

·  Now splice two sheets of plastic in order to achieve full coverage. Cut 2 pieces of plastic at 30 feet. This will give you two, 20’ x 30’ pieces. You will splice the 30’ sections, giving you one big sheet of 38’x30’.

·  Use the clips to attach the plastic to the pipe legs. Clip everywhere you think it needs it.

METHOD 2[2]

PARTS

·  16 ½ inch heavy duty PVC pipe (30 inch lengths) for stakes

·  16 ¾ inch light duty PVC pipe (10ft lengths) for ribs

·  7 ¾ inch light duty PVC pipe (34 inch lengths),for ridgeline

·  2 ¾ inch PVC tee connector (3 way)

·  6 ¾ inch PVC cross connector (4 way)

·  1 20’ x 25’ sheet of clear visqueen type plastic

·  16 1” black poly pipe (8 inch lengths), for clips

·  Optional: 8 ½ inch PVC pipe (12 inch lengths) to reinforce joints

·  Optional: 1 10’x25’ sheet of clear plastic for ends

·  Optional: 12 large binder clips

TOOLS NEEDED

·  Hacksaw

·  Rubber Mallet

·  Utility Knife

·  25’ tape measure

·  Drill with 5/8” spading bit

INSTRUCTIONS

·  Mark out where in your garden your hoop house will be placed. To ensure that the sides are all parallel and square, measure across the diagonals: Both distances should be the same.

·  Collect all your separate parts.

·  Drive a stake into the ground every 36” along the two sides. Try to get them as straight as possible.

·  Put up all the separate hoops first then connect the ridge afterward. Each of the two end hoops is made using two 10' lengths of 3/4" PVC, joined with a PVC tee. The other six hoops use the PVC crosses in place of the PVC tees.

·  The two ends of each hoop slide easily over the 1/2" PVC stakes. If the stakes aren't in the ground perfectly straight, don't worry about it; the pressure from the hoops tends to even out their alignment somewhat.

·  Connect the ridgeline. Starting at one end of the hoop house, connect the hoops at the top, using the 34-inch sections of 3/4" PVC. Use the rubber mallet to set each section as far into the connectors as possible. Note that the ridgeline will be slightly shorter than 21 feet, for increased stability.

METHOD 3[3]

MATERIALS

·  Five 20ft pieces of 5/8 inch rebar (cut into 1/3 to about 6 ft lengths.

·  Seven 20ft lengths of 1” schedule 40 PVC with a small hole drilled dead center at 10 ft.

·  Two 20 foot lengths of 1” schedule 40 PVC (cut into 20” pieces).

·  84 ft of ½ schedule 40 PVC cut into 4 ft lengths.

·  About 80ft of 2x4 treated wood

·  4 treated 8ft fence posts

·  40x24 ft of UV stabilized polyethylene

·  60 2 and ½ fence staples

INSTRUCTIONS

1. Start by stretching a string along where you want the two long sides of the greenhouse to be. Then pound in your 6 foot long pieces of rebar every 4 feet in a straight line leaving 48 inches protruding from the ground. It is important that they be vertical and within ½ inch of the 48 inch target.

2. Nail on 2X6 runner to the rebar stakes. This will give you something to nail the polyethylene onto later. You can use 60 2 ½ inch fence staples. (In the picture left we put the PVC on before attaching the 2X6. This was a pain as you had to hold up the PVC while you nailed the rebar.)

3. Slide the 20 inch pieces of PVC over the rebar stakes.

* make sure no sharps are exposed: wire ends, rebar, rough pipe, etc. It will latter tear the plastic.

4. Place the 20 foot pieces of PVC on the rebar stakes. (Don't put it all the way down on one side and then do the other. Have friend do one side while you do the other, both a little at a time.

*When you first slide the pipes on, the holes you drilled MUST be horizontal (parallel to the ground). Wait about an hour and you will not be about to twist the pipe to correct the problem. The vertical rebar will bend inward as the PVC flexes. This grabs the rebar and locks up the PVC .

5. Now you can slide the wire through the holes in the PVC and then through the eight four foot pieces of PVC along the roof
6. To keep the ribs of this greenhouse from shifting horizontally wire the four foot lengths of PVC pipe with copper or baling wire. Make sure you wrap the wire so the PVC is forced inward not outward.
* This side wall and top tie is VERY,VERY important. If the walls can separate snow or even hail will collapse the structure. The greenhouse will stand up to about a foot (2 foot?) of snow with the ties, two inches without them. If the frame stays together the snow will slide off, if the structure pulls apart the snow can build up to a weight of a 1956 Buick. This greenhouse will not support a Buick on it.

7. Finally you need to build the two end walls with doors. You should put a door on both sides as it will vent better. Either use 10 foot vertical posts (4X4) buried 3-4 feet for doorway frame or 8 foot posts with bracing back to runners (as shown). The two end walls have to be well built and cannot be floppy. They have to stay vertical so the pvc cannot separate. The door needs to be tight enough so that gusts of wind cannot inflate your greenhouse.

Drive a few nails horizontally into the base of the posts and bury them. This will help give your posts some grip in the ground. Little mini-twisters love to hit our greenhouses and blow them up. 40 MPH winds coming in from both sides test your construction. (Our fiberglass greenhouses are cleated with lath because of this problem. Our mini-twisters have blown up some barns in the area.)

8. Last of all have someone help you, one person on each side, slide the plastic over your rib cage. Attach each end by rapping the end of your plastic around pieces of lath and then nail the lath to the triangular end walls and to that long 2X6 along the bottom.

[1] http://www.plumeria101.com/howto.html

[2] http://westsidegardener.com/howto/hoophouse.html

[3] http://www.laspilitas.com/garden/howto/greenhouse.html