Trellises are often made of slats, as shown in Fig. 18, but these are always less durable than the wire trellises and more expensive to keep in repair; and in the older portions of the country, where timber is dear, they are also more expensive at the outset. They catch the wind, and, not being held together by continuous strands, are likely to blow down in sections. Fuller particulars concerning the styles of trellis are given in the discussions of the different systems of training.
_Tying._--Probably the best material for tying the canes and shoots to the trellis is raffia. This is a bast-like material which comes in skeins and which can be bought of seedsmen and nurserymen for about 20 cents a pound. A pound will suffice to tie a quarter of an acre of upright training throughout the season. Raffia is obtained from the strippings of an oriental palm (_Raphia Ruffia_). Wool-twine is also still largely used for tying, but it is not so cheap and handy as raffia, and it usually has to be cut when the trellis is stripped at the winter pruning, while the raffia breaks with a quick pull of the vine. Some complain that the raffia is not strong enough to hold the vine during the season, but it can easily be doubled. Osier willows are much used for tying up the canes in the spring, and also for summer tying, especially in the nursery regions where the slender trimmings of the cultivated osier willows are easily procured. Wild willows are often used if they can be obtained handily. These willows are tied up in a small bundle, which is held upon the back above the hips by a cord passed about the body. The butts project under the right hand, if the person is right-handed, and the strands are pulled out as needed. The butt is first used, the tie being made with a twist and tuck, the strand is then cut off with a knife, and the twig is operated in like manner until it is used up. When wool-twine is used, the ball is often held in front of the workman by a cord which is tied about it and then passed about the waist. The ball is unwound from the inside, and it will hold its shape until the end becomes so short that it will easily drag upon the ground. Some workmen carry the ball in a bag, after the manner of carrying seed-corn. Raffia is not so easily carried in the field as the wool-twine or the willow, and this fact interferes with its popularity. Green rye-straw, cut directly from the field, is much used for tying the shoots in summer. Small wire, about two-thirds the size of broom-wire, is used occasionally for tying up the canes in spring, but it must be used with care or it will injure the vine. Corn-husks are also employed for this purpose when they can be secured. Bass-bark is sometimes used for tying, but in most of the grape regions it is difficult to secure, and it has no advantage over raffia.