Determine the amount of space available for the grape trellis. Plant the grape vines 4 to 8 feet apart, according to the space available and the desired number of vines. Space the posts 12 to 24 feet apart in the rows. If spacing the grapevines 4 feet apart, space the metal poles 12 feet apart. If spacing the grapevines 8 feet apart, space the metal poles 24 feet apart.
Choose a metal pole that will not rust, such as an iron or stainless steel pole. Grapevines require several years to produce fruit; it is therefore important to choose a metal pole that will withstand moist and dry weather conditions.
Dig post holes 2 feet deep, spacing them according to the available area. Employ a level to assure that the poles are vertically aligned. Refill each hole with dirt or concrete. Concrete is recommended to assure that the poles remain vertically aligned through time.
Run wires, securing them to the metal poles. Stretch the wires taut. Run the first wire 3 inches from the ground. Run the second wire 2 feet from the ground. Run the third wire 5 feet from the ground. Use a high-quality wire, such as a galvanized steel wire. A poor quality wire will eventually break, and the grapevine's support will be compromised, potentially causing harm to the vine.