When laden with clusters of fruit, grapevines may weigh hundreds of lbs. To support a row of healthy grapevines, train vines to strong grape trellises built from high-quality materials. A simple two-wire trellis will span a row 60 to 90 feet long. Though the wire used could support vines along a 4,000-foot row, for longer spans a more complicated end brace should be used.
Lay one 9-foot post at each end of the row. Pace the distance between the posts and count the steps. Step off one-third the total number of paces and lay one 8-foot post at that point. Step off another third of the total distance and drop the second 8-foot post there.
Set end posts in the ground 3 feet deep and angled away from the line of the trellis by 45 degrees. When finished, the top of the post should be 5 feet from ground level. Dig a slanted hole 2 feet deep -- begin with a vertical hole and trim away the outer side. Set the end post in the hole, adjust the angle and drive it 1 foot deeper with the sledge. A plumb bob suspended from the post's top should touch the ground 32 inches from where the post enters the ground. Set a 9-foot post at the other end of the row, angled the opposite way.
Set 8-foot stretcher posts 3 feet deep at their previously measured locations and exactly in line with the end posts. Dig post holes 2 feet deep, set the posts in place and drive them 1 foot deeper. Adjust for a perfectly vertical set. Use the tamping bar to firm the ground tightly around them.
Set a 6-foot anchor post at each end of the row. Dig post holes 3 feet deep 60 inches from the end posts and in perfect line with the row. Set the posts in place and drive them 2 feet deeper. Posts should be vertical or leaning slightly away from the row. Tamp the posts in place.
Fasten two levels of high-tension trellis wire on the stretcher posts at 30 inches and 58 inches above ground level. The wire should run loose in the fencing staples. Run the top wire through a staple in the top of one end post and around the anchor post near the ground. Twist the wire tightly around itself and clamp with a wire crimp. Staple the bottom run at 30 inches above ground on the end post and fasten it to the anchor post in the same fashion.
Double a 6-foot section of fence wire around the other anchor post and twist the ends together in a long tight spiral. Pass the doubled wire through the open end of a line stretcher and crimp in place. Repeat with a second section of wire and a second line stretcher. Run the end of each stretcher wire through the cog on one line stretcher. Take up slack by pulling the wire through the cog and use the line stretcher handle to pull the trellis tight.