How to Build a High-Tunnel Greenhouse

Posted by in Home Improvement Tips, on August 20, 2016

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Roger Cook helps a homeowner build a simple, affordable backyard greenhouse. (See the shopping list, tools, and steps below.)

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Shopping List for How to Build a High-Tunnel Greenhouse:
– 1-inch-diameter PVC pipe, to create frame of high tunnel
– 1 1/4-inch-diameter PVC pipe and reducer coupling, to make sleeve that fits over galvanized pipe
– Pressure-treated 2x4s, for building end walls and base
– Pressure-treated 2x2s, for framing two doors
– 4-mil clear plastic sheeting, to cover the PVC frame
– 3-inch screws, for attaching 2x4s
– Galvanized pipe, to secure the PVC pipe to the ground
– PVC primer and cement, for gluing together PVC pipe and fittings
– Metal pipe brackets with 1 1/4-inch screws and washers, used to secure PVC pipe to 2×4 base
– Six 3-inch butt hinges, for hanging two doors
– 1/4-inch staples, to secure the plastic sheeting

Tools List for How to Build a High-Tunnel Greenhouse:
– Cordless drill, to drill holes
– Impact driver, for driving screws
– Circular saw, to cut 2x4s
– Auger, to drill holes in soil
– Small sledgehammer, for pounding in galvanized pipe
– PVC saw, to cut plastic pipe
– Staple gun, for attaching the plastic sheeting
– Utility knife, to cut plastic sheeting

Steps for How to Build a High-Tunnel Greenhouse:
1. Fasten together the 2×4 base with 3-inch screws.
2. Use a drill and auger to bore 1 [FRACTION 12]-inch-diameter holes into the ground inside each corner of the 2×4 base. Bore two more holes, evenly spaced, along each long side of the 2×4 base.
3. Onto each end of the 1-inch-diamenter PVC pipes attach a reducing coupling and short section of 1 1/4-inch PVC pipe. Glue on the parts with PVC primer and cement.
4. Slip one end of the PVC pipe onto one of the galvanized pipes. Then bend the PVC and slip its other end onto the galvanized pipe protruding from the opposite corner.
5. Repeat the previous step to install the three remaining PVC pipes.
6. Secure the ends of each PVC pipe to the 2×4 base with U-shaped metal pipe brackets. Attach the brackets with 1 1/4-inch screws and washers.
7. Build two doorframes out of 2x4s, then screw one to each end of the 2×4 base.
8. Cut diagonal 2×4 braces and install one to each side of both doorframes.
9. Next, cut two long 2×4 beams to span the length of the greenhouse. Screw the ends of the beams to the doorframes.
10. Build two doors out of pressure-treated 2x2s.
11. Set the doors in the doorframes and attach each one with three 3-inch butt hinges.
12. Screw a short wood block to the doorframe to act as a latch.
13. Cover the entire PVC-pipe frame with 4-mil plastic sheeting.
14. Secure the plastic sheeting to the 2x4s with 1/4-inch staples, spaced 3 inches apart.
15. Also, staple the plastic to the doorframes and to each door.[BR]
16. Use a utility knife to cut the plastic sheeting around each door.

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