Line posts are also about 8 feet long, but with a diameter of 3 inches. They are set about 2 feet into the ground and are spaced about 24 feet apart within the row. Galvanized wire is strung between the line posts. Galvanized wire is recommended because it is durable and does not cause serious wire chafing of young vines. Wires are fastened to the line posts with ordinary staples.
Wire placement is determined by the training system to be followed.
For example, a Four-Cane Kniffin system would use 2 wires, one 3 feet high and the second 6 feet high. In the Single Curtain system, the single wire should be about 6 feet high. Wires are secured to end posts in various ways. A common method is to wind the wire around the post once or twice and then twist the end several times around the wire as it is stretched to the next post. Some growers use special devices to attach the wires to the end posts because they simplify tightening of the wires.