The trellis is a considerable item in the grape-grower's budget, since it must be renewed every fifteen years or thereabouts. Wires are strung in the North at the end of the second season after planting, but in the South the growth is often so great that the wires must be put up at the end of the first season. Trellises are of the same general style for commercial vineyards; namely, two or three wires tautly stretched on firmly set posts. Occasionally slat trellises are put up in gardens but these are not to be recommended for any but ornamental purposes.

Posts.

Strong, durable posts of chestnut, locust, cedar, oak or reënforced cement are placed at such distance apart that two or three vines can be set between each two posts. The distance apart depends on the distance between vines, although the tendency now is to have three vines between two posts. The posts are from six to eight feet in length, the heaviest being used as end posts. In hard stony soils it may be necessary to set the end posts with a spade, but usually sharpened posts can be driven into holes made with a crowbar. In driving, the operator stands on a wagon hauled by a horse and uses a ten- or twelve-pound maul. The posts are driven to a depth of eighteen or twenty-four inches for the end posts. However set, the posts must stand firm to hold the load of vines and fruit. The end posts must be braced. As good a brace as any is made from a four-by-four timber, notched to fit the post halfway up from the ground, and extending obliquely to the ground, where it is held by a four-by-four stake. A two-wire trellis and a common method of bracing end posts are shown in [Fig. 15]. The posts on hillsides must lean slightly up-hill, otherwise they will almost certainly sooner or later tilt down the slope. The posts are usually permitted to stand a little higher at first than necessary so that they may be driven down should occasion call; driving is usually done in the early spring.

Fig. 15. A trellis and a common method of bracing end posts.

Wire for the trellis.

Four sizes of wire are in common use for vineyard trellises; nos. 9, 10, 11 and 12. Number 9, the heaviest, is often used for the top wire with lighter wires lower. The following figures show the length of wire in a ton: