Grape vines grow very large in size, some even as long as 20 feet. These vines, whether grown at home for domestic use or in a vineyard for commercial purposes, need support of some sort to raise them off the ground and ensure good air circulation and a maximum amount of sunlight. A vineyard trellis is a simple structure a gardener can make with a few inexpensive materials. Your trellis will consist of an end post and brace post, and one line post for each grape vine.
Place a shovel or post hole digger over the ground and dig a 3-foot-deep hole. Collect the dirt in a wheelbarrow. Carefully stand an 8-foot-long, 4-inch-wide post into the hole. This is called the end post.
Measure 6 feet from the end post and mark the spot on the ground with spray paint or powdered chalk. Dig another 3-foot-deep hole over the marked spot with a shovel or post hole digger and insert a second 8-foot-long and 4-inch-wide wooden post into it. This is called the brace post.
Lay a wooden 4-by-4 post over the top of the end post and extend it so it is over the top of the brace post as well. Make sure it is longer than 8 feet so it protrudes from both the ends by at least a foot.
Measure 20 feet from the brace post and mark the spot on the ground with spray paint or powdered chalk. Dig a 3-foot-deep hole over the spot with a post hole digger or shovel, and insert an 8-foot-long wooden post with a 3-inch diameter into it. This is called the line post. Ideally, you need one line post per grape vine, so the number of line posts you install depends on the size of your crop. Space all line posts 20 feet apart.
Wind a 9-gauge galvanized steel wire around the top of the brace post. Extend it diagonally to the lower corner of the end post. Twist it around the post tightly several times with pliers so it is secure, and cut off any excess amount with wire cutters.
Staple a length of 9-gauge galvanized steel wire to the top of the last line post with 2- to 2½-inch staples. Extend it to the top of the next line post, pulling it taut so it is straight and staple it in place. Continue this procedure until the wire is stapled to the top of the end post.