2. Basic Structure of a PVC Greenhouse
Suggested Basic Materials List
? 2?6 ? treated lumber
? 3/4" white PVC pipe
? 1/2" x 4' rebar
? 6mm plastic
? Wood lath strips
? Wood staples
? Zip ties
? Nails and screws
? Perforated galvanized steel strapping
? Door hinges and handle
The simplest PVC structure is a classic hoop shape. This structure can be as narrow or wide as the PVC piping you have available, and it can be as long as you'd like. A 12 x 14 foot greenhouse is a good size for propagation, transplanting and growing plants for a beginner. Remember, you can always add to the length of your structure if you outgrow it.
You can purchase stock 3/4" PVC pipe in 20 foot lengths. This length will give you six foot headroom in a 12 foot wide greenhouse. If you're very tall, you can reduce the width of your structure to increase the height in the center of the room. PVC pipe is also available in 10 foot lengths, which are easier to haul. You can couple two 10 foot lengths together if you aren't able to transport 20 foot lengths.
Using treated 2x6 boards, build a frame to fit the space you've laid out with the string line or paint. This is the inside perimeter of your greenhouse.
Use four-foot long, 1/2" rebar to stake your PVC poles. Hammer the stakes two feet into the ground on the outside of the wooden frame. These bars should be placed equally along both sides of the building. Two to three feet is recommended for spacing. Make sure you measure properly so the PVC bows are straight.
Now, slide one end of the PVC pipe over the rebar, and slide the other end over the corresponding rebar directly across from it. After you've attached all your PVC piping, you can secure them by screwing a piece of perforated galvanized steel strapping around the pipe and onto the wooden frame.
Once you've gotten all the hoops in place, cut a piece of PVC pipe the length of your building. This will be the rib that holds the hoops in place. Mount the rib underneath the hoops and secure it with plastic twist ties at each intersection.
You're now ready to cover your framework with the sheet plastic. Unroll and drape the plastic over the frame. Leave ample material to cover both ends. You'll work from the center to the ends on both sides of the greenhouse, and maintain a taut, firm tension to the material. Bring the plastic down over the 2x6, cover the material with a piece of lath, and staple it in place.
If you plan to have a proper door at one end, you'll need to build a wooden rectangular frame to support your door. Build a framework that fits within the door frame, mount it with hinges, cover it with plastic and add a handle and latching mechanism. If you're not much of a carpenter, you can simply use the plastic sheeting much like a tent flap and pull it back to enter and let it down to close the opening.
The back end of the building can simply be covered with the plastic sheeting. Use the same method of applying lath and staples that you used to secure the sides.
Greenhouse Kits from Woodcraft: