Imagine a cool breeze and dappled shade and the sweet smell of ripening grapes, and you've got a little piece of heaven. Building a grapevine arbor is a good weekend project, and you can expect it to take several years before the vines fill in to create that enclosed, shady retreat. But you won't regret the time you put into this project; not only will you have a delightful outdoor space, you'll have a snack waiting when you get there.
Measure off the space in which you want to build your grapevine arbor. You need to create either a square or a rectangle; it's best to put it in the most level part of the area. Keep it at 8 feet or under on the longest side; choose an 8-foot square if you want to avoid cutting the posts that will be horizontal supports.
Mark each corner and measure the space between them to be sure you have set them the correct distance apart. The posts need to be "inside" your measurement, so that the outermost side of the post is at the 8-foot mark.
Dig a hole 2 feet deep in each corner.
Place one 2-by-4 post into a corner hole. Pour one bag of concrete mix into the hole. Then use a hose to thoroughly wet the concrete inside the hole. Hold the post steady and straight for a few moments while the concrete sets.
Repeat Step 4 with the three additional corners.
Allow the concrete to set for 24 hours.
Cut the remaining 2-by-4 posts to the total length of your longest side (if you are building a rectangle-shaped arbor) or simply to the length of two sides of the square if you created a square smaller than 8 feet across.
Lay a 2-by-4 post on top of the two corner posts on one side. Nail or screw into place.
Repeat on the opposite horizontal side with the remaining 2-by-4 post.
Install eye screws along this horizontal support, starting at the outside edge and installing one approximately every foot down. Repeat with corresponding eye screws along the other horizontal support post.
Cut your cable into eight pieces that are 1 foot longer than the distance across the arbor (perpendicular to the horizontal supports). Wrap one end of a piece of cable through one eye screw; crimp it together firmly; stretch it across to the corresponding eye screw; run it through the ring; and crimp it together. Clip any excess. Repeat with the remaining pieces of cable through the additional eye screws.
Plant grapevines at the four corners of the arbor. As the vines grow, train them up the posts and toward the cables.