How to Build Galvanized-Pipe Greenhouses

Building the Base

• 1

  Lay landscaping fabric on the leveled greenhouse site. Attach it to the ground at 18-inch intervals using landscape staples. Measure the dimensions of the greenhouse.

• 2

  Build a simple base from pressure-treated lumber and screws to fit around the perimeter of the landscaping fabric. Cut the long sections of the base to the exact length of the greenhouse. Subtract 3 inches from the width and cut the wide sections to this dimension. Fit the wide sections inside the long sections and screw them together through the ends.

• 3

  Cut sections of 1-inch galvanized pipe that are about 3 feet long using the hacksaw. Space them 2 to 3 feet apart along the length of the greenhouse, being sure to place one set on either end. Hammer them tight against the wooden frame, about 18 inches into the ground.

Erecting the Hoops

• 4

  Bend the 3/4-inch galvanized pipe into hoops per the instructions included with your galvanized pipe bender -- the angles and amount of material will vary depending on the width of your structure. Fasten the hoop sections together through the tabs with 1/2-inch self-tapping screws. Slide one end of the hoop into a 1-inch pipe on one side of the greenhouse area as deeply as you can, then carefully slide the other end into the pipe on the opposite side -- you may have to compress the hoop a little to make it fit. Secure the hoop from the inside of the structure with 1/2-inch self-tapping screws. Repeat for all hoops.

• 5

  Measure the length of the structure and cut a section of 3/4-inch galvanized pipe about 1/4 inch shorter than this measurement. Attach the pipe on the inside of the structure to the topmost part of the arch using 1-inch self-tapping screws, beginning with the center hoop and working outward. Repeat for the points of the hoop where the arch becomes pronounced (3 to 5 feet from the ground on each side).

• 6

  Unroll the rabbit wire along the ground. Cut it just long enough to fit the length of the greenhouse. Tie the rabbit wire to the outside of the structure, along the length of the building with the center at the peak of the roof and the ties facing inside the building. This will help prevent sagging plastic during heavy precipitation.

Hanging the Plastic Sheeting

• 7

  Drape the sheet plastic over the top of the greenhouse, leaving about 1 foot of excess on the ground on either side of the structure -- be careful not to catch it on the rabbit wire. Overlap the seams by 4 inches if your plastic isn't as wide as your structure. Leave the flat ends for last. Tape the plastic to the galvanized pipe using the clear fiber-reinforced tape. If wind is a problem, tape the entire length of the pipe -- if not, less tape may hold the plastic securely. Tape to the purlins (the cross-bars you installed to stabilized the hoops) as well as the hoops and run a length of tape along any seams in the plastic.

• 8

  Using sheet plastic, attach the solid end of the greenhouse by draping the material from the top to the bottom and taping it securely to the hoop and to itself. Cut off or tuck in any excess plastic as you work.

• 9

  Attach the open end in sections -- many hoop house builders divide the material into two sections, leaving the middle overlapping, but unfastened. You can secure the two sides to themselves with an industrial-strength hook-and-loop fastener if you're concerned about heat loss.