Only two wires are used in the true Kniffin trellis. The end posts are usually set in holes, rather than driven, to render them solid, and they should always be well braced. The intermediate posts are driven, and they usually stand between every alternate vine, or twenty feet apart if the vines are ten feet apart—which is a common distance for the most vigorous varieties. For the strong-growing varieties, the top wire is placed from five and one-half to six feet above the ground. Five feet nine inches is a popular height. The posts will heave sufficiently to bring the height to six feet, although it is best to "tap" the posts every spring with a maul in order to drive them back and make them firm. The lower wire is usually placed at three and one-half feet. Delawares, if trained Kniffin, should not stand above five feet four inches, or at most five feet six inches. Strong vines on good soil are often put onto the trellis the second year, although it is a commoner practice, perhaps, to stake them the second season, as already explained ([page 27]), and put them on the wires the third season. The year following the tying to the trellis, the vine should bear a partial crop. The vine is usually carried directly to the top wire the first season of training, although it is the practice of some growers, especially outside the Hudson valley, to stop the trunk at the lower wire the first year of permanent training, and to carry it to the top wire the following year.
Yields from good Kniffin vines will average fully as high and perhaps higher than from other species of training. W. D. Barns, of Orange county, New York, has had an annual average of twenty-six pounds of Concords to the vine for nine years, 1,550 vines being considered in the calculation. While the Delaware is not so well suited to the Kniffin system as stronger varieties, it can nevertheless be trained in this manner with success, as the following average yields obtained by Mr. Barns from 200 vines set in 1881 will show:
| 1886 | 8½ | pounds | to | the | vine. |
| 1887 | 11¾ | " | " | " | " |
| 1888 | 8 | " | " | " | " |
| 1889 | 9½ | " | " | " | " |
| 1890 | 7 | " | " | " | " |
| 1891 | 16 | " | " | " | " |
| 1892 | 13 | " | " | " | " |
Modifications of the Four-Cane Kniffin.—Various modifications of this original four-cane Kniffin are in use. The Kniffin idea is often carelessly applied to a rack trellis. In such cases, several canes were allowed to grow where only two should have been left. [Fig. 23] is a common but poor style of Kniffin used in some of the large new vineyards of western New York. It differs from the type in the training of the young wood. These shoots, instead of being allowed to hang at will, are carried out horizontally and either tied to the wire or twisted around it. The advantage urged for this modification is the little injury done by wind, but, as a matter of practice, it affords less protection than the true drooping Kniffin, for in the latter the shoots from the upper cane soon cling to the lower wire, and the shoots from both tiers of canes protect each other below the lower wire. There are three serious disadvantages to this holding up of the shoots,—it makes unnecessary labor, the canes are likely to make wood or "bull canes" ([see page 50]) at the expense of fruit, and the fruit is bunched together on the vines.
23. A POOR TYPE OF KNIFFIN.
Another common modification of the four-cane Kniffin is that shown in [fig. 24], in which a crotch or Y is made in the trunk. This crotch is used in the belief that the necessary sap supply is thereby more readily deflected into the lower arms than by the system of side spurring on a straight or continuous trunk. This is probably a fallacy, and may have arisen from the attempt to grow as heavy canes on the lower wire as on the upper one. Nevertheless, this modification is in common use in western New York and elsewhere.
