Trellising and spacing adjust to modern needs
The early trellis systems for growing raisin and wine grapes were quite simple. For head-trained, spur-pruned vines, a single 2- by 2-inch split redwood stake or other wood was placed at each vine, and the vine was then trained to the stake. For cordon- or head-trained, cane-pruned vines, one or two wires were fastened to a 5-or 6-foot stake at each vine 34 to 48 inches from the ground and held taut by firmly set end posts. This type of trellis in California has withstood the test of time and is probably the most widely used for growing raisin and wine grapes; however, the trend now is to place the wires higher to facilitate mechanical harvesting.