The second year's work is largely a repetition of that of the first. The vines are permitted to reach the peak of the house and are again stopped by pinching. A considerable number of laterals spring up on each side of the main vine, and these must be thinned as they develop to stand at the distance apart of the wires to which they are fastened. This is pre-supposing that the gardener has chosen the spur method of pruning, the method generally used in America and the one, all things considered, which gives best results. The selection of the laterals the second year, therefore, is a matter of much importance since spurs are to be developed from them. Care should be taken to have these spurs regularly distributed over the length of the vine. This second year, grapes must not be permitted to develop on the terminal shoots, but a few clusters may be taken from the laterals in which case the laterals are pinched two buds beyond the cluster, the pinching continuing throughout the season if the laterals persist in breaking, as they will do in most cases. At the end of the season, the terminal is shortened at least one-half, and the laterals are pinched back to a bud as close as possible to the main stem. The vines are then put down for the winter as at the close of the first season.
The work of the third season is a repetition of that of the second, with the exception that the vine is permitted to fruit throughout its whole length, although not more than one pound of fruit to a foot of main vine is permitted. The plants are now established and the only pruning in this and succeeding years is to cut the laterals at the close of each season close to the main stem, leaving strong healthy buds of which at least one, usually more, will be found close to the stem. If more than one bud starts, only the strongest is chosen, although often an extra one is needed to fill a vacancy on the opposite side. After the third or fourth season, depending somewhat on the variety, two pounds of fruit or more to the foot of the main stem can be permitted. The novice, however, is likely to permit his vines to overbear with the result that the crop is cast, or the berries rattle, or the fruit turns sour before ripening. From the beginning to the finish of the season, in this method of pruning, much pinching of laterals is required. No hard and fast rule can be laid down for this pinching, but, roughly speaking, all new growth beyond the second joint from the cluster should be pinched out as fast as it shows. With most varieties, this means that the lateral is kept about eighteen inches from the main stem. After a few years, well-developed spurs form at the base of the original laterals, and from these spurs the new wood comes year after year.
An alternative method of pruning is to permit the new canes to grow up from a bud near the ground each season. When the vine is well established, this new cane is fruited throughout its entire length, the laterals being pinched as described under the spur method. This method of pruning is known as "the long cane method." Gardeners hold that they can grow better fruit with this than with the spur method, but the difficulties are greater and the crop is not as large.
Care of the Vines
With the cultivation of all varieties indoors, more clusters set than the vines can carry. This means that a part of the clusters must be removed, an operation that depends on the variety and one that requires experience and judgment on the part of the gardener. Roughly speaking, half the clusters are taken, leaving the other half as evenly distributed on each side of the vine as possible. The time to take these clusters is also a delicate matter, since some sorts are shy in setting and the clusters must not be taken until the berries are formed and it can be seen how large the crop will be. As a rule, however, this thinning of clusters may be begun as soon as the form of the cluster can be seen.
It is very necessary also, especially with all sorts bearing large berries, that grapes be thinned in the cluster. The time to thin the cluster varies with the variety. Sorts which set fruit freely can be thinned sooner than those which are shy in setting. On the one hand, the thinning must not be done too soon as it cannot be told until the berries are of fair size which have set seed and which have not; however, if thinning is neglected too long, the berries become over-crowded and the task becomes difficult. The thinning is performed with slender scissors, and the bunches must not be touched with the hand, as touching impairs the bloom and disfigures the fruit. The clusters are turned and steadied by a small piece of pencil-shaped wood. Thinning is practiced not only to permit the berries to attain their full size but also to permit the bunches to attain as great size as possible. If too severely thinned, the clusters flatten out after maturity. This is especially the case when too many berries are taken from the center of the bunch. A large cluster of grapes is made up of several small clusters, making it necessary to tie up the upper clusters or shoulders of the bunch to permit the berries to swell without being thinned too severely. Grapes intended for long keeping require more thinning than those to be used at once after picking, since, in keeping, the berries mold or damp-off in the center of the bunch if it is too compact.
The vines in the grapery must be watered with considerable care. The amount of water to be used depends on the composition of the borders and the season of growth. If the border is loose and well-drained, the supply of water must be large; if close and retentive, but a small amount of moisture is required. Watering must not be done during the period of blossoming, since dry air is necessary for proper pollination. When the grapes begin to show color, the vines are heavily watered, after which little if any water is applied. Some gardeners mulch the vines with hay to retain the moisture in the house and keep the atmosphere dry.
Ventilating the grapery is another important detail of the season's work. Proper ventilation is difficult to secure in the early spring months when the dryness of the sun on the one hand, and cold air on the other, make it difficult to avoid draughts and regulate the temperature. Another troublesome time is when the grapes begin to color, as it is then necessary for the grapery to have air at night; but when too much air enters, there is danger from mildew. Towards the end of the season, all parts of the plant become harder in texture and the grapery may then be more generously aired. After the fruit is cut, the houses are ventilated in full so that the wood may ripen properly.