Caring for Grape Vines

GROWING GRAPES INDOORS

SOILS

The best soils are light and sandy, and well drained, but should not be allowed to dry out during the fruiting season. Vines do not like a poor soil, they have an extensive root run and are gross feeders.

PREPARATION

Good drainage is essential tor vines so if the sub-soil is heavy clay dig this out to a depth of 2 ft and incorporate 5-9 ins of drainage material, broken up brick and rubble. Fill the remainder of the hole with good soil and well rotted manure, and give a dressing of Va oz. Sulphate of Potash, 4-6 oz. Bone Meal and 5-6 oz. ground limestone.

PLANTING

If more than one vine is to be planted in the greenhouse, plant at 5 ft apart for single rods and 8 ft apart for double rods. Plant against the glass in a lean-to house. Or on both sides of a span house. In both cases the rods are grown towards the ridge.

Remove the plant from its pot, and plant in a hole big enough to accept the root ball, firm and water in. Tie the rod to a cane. Prune the vine to within 1 2 ins of its base by the middle of January following planting, do not prune any later than this otherwise severe ‘bleeding’ will occur.

TRAINING

First year. After pruning and when growth commences select the strongest shoot, removing the others and allow this to grow and develop as the main rod. This single rod should nrow anything up to 8-9 ft in the first season. Any side shoots and tendrils which develop in the first year should be removed. At the end of the first growing season and after the plant has lost its leaves cut the rod back to 4-5 ft into the mature wood. Rods can be trained singly or in multiples. In the latter case they are grown horizontally to fill the required space.

Second year. Train the rods as in the first year. When the rods have reached the ridge of the greenhouse pinch the top out of the rod. Allow laterals to form either side of the rod at approximately 1 8 ins distance. When these have grown to 1 8-24 ins prune back to 1 2 ins and tie in to wire supports. Providing growth has been satisfactory in the second year, the rods should produce its first bunches of flowers and subsequently fruit, only one or two bunches should be allowed to develop, remove the remainder. In the autumn and after leaf fall prune rod or rods to their final height and shorten all laterals to two buds.

Third year. Laterals will develop from the previous seasons pruning, select the strongest of these and remove the remainder when they are 2-3 ins long. As tendrils appear remove these also. In the third year only allow six to eight bunches of fruit to develop, stopping the lateral on which they are produced two to three leaves after the bunches. Laterals which produce no fruit should be allowed to grow and stopped at 1 8 ins.

When the vine has settled down and growing strongly, approximately one bunch of fruit per foot of main rod should be allowed to develop.

Subsequently pruning is the same every year as outlined above, keeping in mind that grapes are always produced on the newly produced laterals. Pruning and removing of young shoots must always be done early in the season, under no circumstances should large vigorous shoots be pruned, they will bleed profusely and weaken the plant.

POLLINATION

Grapes are self-fertile but their setting can be improved by shaking the rods daily when in flower or passing a cupped hand over the flowers at regular intervals. Never allow more bunches to develop than the plant can cope with. Over cropping produces a disorder known as ‘shanking’ when the berries fail to develop, turn sour and shrivel.

When the berries are forming it is important the bunches are thinned with a pair of grape scissors, this operation may need to be done two or three times as the bunch develops, but should always be done with caution so as not to spoil the eventual size and shape of the bunch.

DAILY ROUTINE

During the development and growth of the vine in the spring it is advisable to spray the vine with water, but this should cease when flowering begins.

Frequent damping down of the floor should be done on warm days to maintain a moist atmosphere.

The vine itself should be watered regularly and fertilized with a high potash fertilizer to aid size and ripening of the berries. During the period when the bunches are developing ventilation is important to prevent condensation on the berries, which causes splitting.

PESTS and DISEASES

Mildew is the most common disease found in grapes. Spray with Dinocap or Benlate beginning in April and continuing after the berries have set.

Red Spider may also be a problem, but good ventilation and maintaining a buoyant moist atmosphere should keep infestations at bay. During the dormant period an application of Tar Oil will clean up the rods.

GROWING GRAPES OUTDOORS

The varieties of grapes for growing outside must be selected with care. It is almost impossible to get a good crop of quality grapes outdoors with varieties which are normally grown in a cold greenhouse.

SITE

Grapes outdoors should either be grown on south or south-west walls which get plenty of sun in order to ripen the berries. Alternatively varieties which are mainly grown for producing wine can be grown on posts and wires in a row running from north to south.

The preparation of the planting position must be as thorough as that for indoor grapes, paying particular attention to drainage. Fertilizers as for indoor grapes. Regular watering is essential making sure that grapes grown on walls never dry out.

PLANTING

Plant the grape in its prepared position taking care not to disturb the roots, if the plant is in full leaf, firm and water well. The following autumn prune down to three-four buds.

TRAINING ON WALLS

Wall trained grapes are usually grown and trained in similar fashion to grapes under glass, that is, as vertical cordons in single or multiple form, each cordon or rod being spaced about 4 ft apart.

TRAINING ON WIRES

The grape is amenable to many forms of training, the one most likely used for vines on wires being the Guyot in single or double form. The Guyot method of pruning is simply a replacement system, whereby the wood which has fruited in the summer is cut out in the winter and selected new snoots are tied in to replace it.

First year. The two strongest shoots should be allowed to grow and develop. Tie in to the cane and remove any tendrils as they appear. Any laterals or sub-laterals which may be produced are pinched back to one or two leaves. In November and not later than December the vine is cut down to 2-3 buds.

Second year. The post and wire support for the vines can either be put in position in the first or second year. Place substantial posts 10 ft apart and ailow 5 ft above ground level. The bottom wire should be 15 ins above the ground, and a double wire 30 ins above ground level is fixed, a third wire 15-18 ins can then be placed above this. During the second summer three shoots are trained up the cane, all others being pinched out. Laterals and sub-laterals are dealt with in the same way as the first year.

In the third winter the double Guyot system begins.

One shoot is tied down to the left on the lowest wire and the other to the right. The remaining shoot is pruned back to three buds. The vine is now ready to produce its first crop in the following summer.

Third year. Allow only a small crop in the first year, three or four bunches, about six the next and then full cropping.

From June onwards train in the fruiting laterals which come from the horizontal arms through the double wires and pinch back to one leaf any sub-laterals. In addition three replacement shoots are trained up the cane. By August the growth should be well above the top wire and this can be pruned back with secateurs or shears to within 4 ins of the top wire, but the replacement shoots should be allowed to grow up to 6 ft or so. These replacements should not be allowed to fruit

In the winter, as soon as possible after leaf fall, the horizontal arms which have fruited are cut out and two replacement shoots are tied in along the lowest wire. The third is cut to three buds and so the Guyot cycle begins again.

DISEASES

Mildew is the main disease prevalent on outdoor vines. Zineb is used for downy mildew and Dinocap for powdery mildew, both may be mixed together and the vines may be sprayed two weeks after flowering, followed by sprays at two to three weekly intervals until ripening commences.

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