Build your own greenhouse with PVC plastic pipe. A design resembling a metal Quonset hut is sturdy, allows for efficient use of materials and takes advantage of PVC's ability to bend without losing strength. With several lengths of PVC pipe and a collection of connectors you can snap this frame together in very little time.
Lay out the base of the frame on smooth level ground, using the 12 foot 10 inch pipes as the sides and the 11 1/2 foot pipes as the front and back.
Slide 3 slip Ts onto each of the side pipes, spacing them three feet from each end and three feet apart.
Connect the corners of the base with the 3-way connectors, making sure the third opening is pointing up.
Drive 5 stakes into the ground along the two sides of the frame, one next to each connector. Leave about 2 inches of the stake above ground.
Slide two slip Ts onto the centres of three of the 19 foot pipes, which will serve as the middle arches of the frame.
Slide a slip T onto the centres of the remaining two 19 foot pipes, which will be the end arches.
Place the ends of the two end arches into the openings of the 3-way connectors at the front and back of the frame, bending them upward so they fit.
Install the ends of the three centre arches into the slip Ts on either of the sides.
Connect the front arch to the second arch by inserting a 3 foot length of pipe in the slip T at the centre of the front arch. Connect the other end of the 3 foot pipe to one of the slip Ts in the second arch. Connect the rest of the arches in the same way.
Drape the large vinyl sheet over the top of the frame so that it hangs over equally on each side.
Secure the large vinyl sheet to the arches using Snap Clamps placed 8 to 10 inches apart.
Cover the front end with the two 6 1/2 foot 6 by 7 foot vinyl sheets, overlapping them by about 6 inches. Attach with Snap Clamps.
Cover the back end with the 12 1/2 foot by 7 foot vinyl sheet. Attach with Snap Clamps.
Glue any fittings that are loose, or secure them with a self-tapping screw.
Tie the frame securely to the stakes with rope.
This simplified structure uses a simple flap for a front door. You can make your structure a little more convenient by building a door out of PVC pipe and attaching it to the front with more slip Ts, two on the front arch and two on the front base pipe. Depending on what you're growing in your greenhouse, you may opt to use plastic netting (for bird protection) or shade cloth (for plants that don't tolerate direct sun) instead of the vinyl sheeting. You can save some money on the project by purchasing a 12 foot length of pipe and cutting it down into the four 3 foot lengths you need.
Do not let children play with loose vinyl sheeting; it is a suffocation hazard. Always wear eye protection when driving stakes or cutting PVC pipe. Do not glue or secure the PVC connectors until the frame is completely assembled, or mistakes may be impossible to correct.