A decorative garden arch has many uses in landscaping such as framing the entryway to a garden, supporting flowering vines and dressing up otherwise bare walkways. While there are archways available for purchase in many garden centres, you can make garden arches for less at home with basic supplies and little building knowledge. Once your garden arch is constructed, it will be ready to dress up your garden and support growing plants.
Lay two of the 2.25 m (7 1/2 feet) posts on the ground, running parallel and spaced 30 cm (1 foot) apart. Slip a 30 cm (1 foot) board between the two long boards at the top, with the board resting on a 10 cm (4 inch) side. Make the boards flush along the top. Secure with two screws at each end of the board.
Slip a second 30 cm (1 foot) board between the two long boards along the bottom. Using a tape measure, adjust the 30 cm (1 foot) board so it starts 15 cm (6 inches) up from the cut ends of the long boards. Secure two screws through each end of the board.
Place a third 30 cm (1 foot) board in the middle between the long boards. Position the middle board so its top edge is exactly 10 cm (4 feet) from the bottom edge of the bottom 30 cm (1 foot) board. Secure with two screws on each end. Repeat Steps 1 through 3 to make a second side unit.
Place a portion of wooden lattice between the two long boards on each side unit. Adjust the lattice so it rests over the bottom and middle 30 cm (1 foot) boards and covers the space between them. Secure with screws at each point where the lattice touches the 30 cm (1 foot) boards.
Lay the two 105 cm (3 1/2 foot) boards on the ground spaced a foot apart. Place the remaining 30 cm (1 foot) board between the two boards and position it in the middle approximately 50 cm (20 inches) from each end. Secure the board with two screws at each end to form the top of the arch.
Stand the two side units parallel on their sides, with the 30 cm (1 foot) boards facing out. Space the units 105 cm (3 1/2 feet) apart. Place the top of the arch between the top of the two wide units with its 30 cm (1 foot) board facing out. Secure the top to the sides with two screws at each top corner.
Place the remaining lattice unit over the top of the arch and secure with screws where it touches the 30 cm (1 foot) boards.
Dig four holes 8 inches deep, spaced far enough apart to form the corners of a 30 cm x 1.2 m (1 by 4 foot) rectangle. Fill the bottom 5 cm (2 inches) of each hole with gravel or concrete mix. Stand the arch upright and slip the bottom 15 cm (6 inches) of exposed post into each hole. Fill in each hole with soil.
Leave the arch looking natural, or use paint or stain to match other garden items.