The ideal length of the two canes varies with different varieties and the distance apart at which the vines are set. Very strong kinds, like Concord and Niagara, can carry ten or twelve buds on each cane, especially if the vines are set more than eight feet apart. Fig. 17 shows half of a Concord vine in which about ten buds were left on each cane. These strong sorts can often carry forty or fifty buds to the vine to advantage, but when this number is left the canes should be four, as explained in the last paragraph. In Delaware and other weak-growing varieties, twenty or twenty-five buds to the vine should be the maximum and only two canes should be left. In short-jointed varieties, the canes are usually cut to the desired length--four to six feet--even if too great a number of buds is left, but the shoots which spring from these extra buds are broken out soon after they start. A Delaware vine which has made an unusually short or weak growth will require fewer buds to be left for next year's top than a neighboring vine of the same variety which has made a strong growth. The Catawba, which is a short but very stiff grower, is usually cut back to six or eight buds, as seen in figs. 13, 14 and 15. The grower soon learns to adjust the pruning to the character of the vine without effort. He has in his mind a certain ideal crop of grapes, perhaps about so many bunches, and he leaves enough buds to produce this amount, allowing, perhaps, ten per cent. of the buds for accidents and barren shoots. He knows, too, that the canes should always be cut back to firm, well-ripened wood. It should be said that mere size of cane does not indicate its value as a fruit-bearing branch. Hard, smooth wood of medium size usually gives better results than the very large and softer canes which are sometimes produced on soils rich in nitrogenous manures. This large and overgrown wood is known as a "bull cane." A cane does not attain its full growth the first year, but will increase in diameter during the second season. The tying therefore, should be sufficiently loose or elastic to allow of growth, although it should be firm enough to hold the cane constantly in place. The cane should not be hung from the wire, but tied close to it, provision being made for the swelling of the wood to twice its diameter. [Illustration: 16. HIGH RENEWAL WITH FOUR CANES.] [Illustration: 17. HIGH RENEWAL COMPLETE.--CONCORD.]