(1) For the first year, allow the vine against a wall to grow freely and attach the shoots loosely to a sturdy bamboo cane around 2 m (7 ft) tall. In the first autumn after planting, select the strongest two shoots and cut them back by half. All the other shoots should be cut away at the base of the vine. The two retained shoots, called ‘rods’, should then be attached to wires on the wall. In future autumns, after leaf-fall, these main stems or rods should also be cut back by about half of the season’s extension growth. Always cut back into ripe wood, which is a reddish brown, to a point 2.5 cm (1 in) beyond a bud. There is no point in keeping green extension growth as it will go mouldy over the winter.
(2) The side-shoots from the main stems should also be cut back in autumn, after harvesting, to two buds. In spring when shoots form on these short spurs, the best two shoots should be retained and the others cut away.
(3) In summer, pinch back the side-shoots growing from the spurs to two leaves beyond a bunch of fruit. Allow just one bunch of fruit to each side-shoot in the first year of fruiting. In the second year you can allow two bunches, and in the third and subsequent years of fruit three bunches can be obtained, depending on the vigour of the vine.
(4) Plant vines to be grown in the open 1.2 m (4 ft) apart against a previously erected framework of wires. Each vine will need a sturdy bamboo cane to support the first season’s growth. In the autumn after planting, select the two strongest shoots and cut them back to 1.2 m (4 ft). Then tie them to the lower wire on either side of the vine to make a T-shape. Cut away all the other shoots at two buds from the base of the vine. The following year, allow one bunch of grapes to each side-shoot and stop the growth at two leaves beyond this point. As with grapes on a wall, you can allow the vine to produce more grapes as it grows more vigorous. Treat the extension growths from the T-shaped rods as if they too were side-shoots.
(5) The buds at the base of the vine will send up new shoots which should be secured to the cane and tucked between the topmost wires. In autumn cut away the rods which have borne fruit at two buds from the base and shorten and tie in the best two new shoots to take their place.
(6) If you wish to grow grapes in a greenhouse, plant the vine outside and lead one main stem through a hole in the glass at the opposite end from the door. The main stem, or rod, is allowed to extend annually vertically at first and then horizontally along a wire on the apex of the greenhouse roof. Put up also a framework of wires under the sloping roof of the greenhouse on the side which gets the sun. These wires should be spaced 30 cm (1 ft) apart.
The pruning routine for a single rod vine in a greenhouse is identical to that for a vine on a wall outdoors. Remember always to cut back the main stem back to a point 2.5 cm (1 in) beyond a bud on reddish wood. When the rod reaches the full length of the green-house, it too is treated as if it were a side-shoot and is trimmed back accordingly.
The side-shoots from the fruiting spurs are tied to the wires under the sloping greenhouse roof. In the first year of fruiting, allow only one bunch of grapes to each side-shoot: stop the growth by pinching back at the second leaf beyond each bunch of fruit. In future years you can increase your grape production according to the vigour of the vine.
Size: Spread of 1.2 to 6m (4 to 20ft), depending on the method of cultivation.
Climate: Temperate to subtropical.
Aspect: Sunny, sheltered and ideally on a southerly slope.
Soil: Well-drained soil enriched with compost.
Yield: 0.5 kg of grapes to every 30 cm of stem (lib to 1ft).
Planting and cultivation
Growing grapes is really no more difficult than growing raspberries. There are varieties for outdoors and others which are best suited to growing in a greenhouse. A vine can be trained on a house wall, or you can grow grapes in the open and have your own vineyard. Vines should be planted between late autumn and late winter in soil which has been well-enriched with compost. In mid-spring give the vine or vines an annual feed of general fertilizer at the rate of 135 gm per sq m (4oz per sq yd) which should be followed by a thick layer of compost around their roots. Water thoroughly during dry spells.
Pruning and training
After planting cut the vine down to about 23 cm (9 in) from soil level. With a vine grown against a sunny wall, allow the vine during the first year to grow freely and tie the shoots to a tall bamboo cane. In autumn select the two strongest shoots and cut them back by their length. All the other shoots should be cut away at ground level. You can then put up two parallel galvanized wires 60 cm (2 ft) apart on the wall secured to ‘vine eyes’. The wires should rise vertically initially and then run horizontally. The shoots by which the vine increases in length, called ‘rods’, should then be lightly tied to the wires. In future years these main stems, or rods, should be allowed to grow freely, but should be cut back each autumn by about half of the season’s new extension growth.
Vines can also be grown in the open on wires stretched horizontally at 60 cm (2 ft) and 1.2 m (4 ft) from the ground. At the 1.2 m (4ft) level the normal practice is to have wires on either side of the posts so that the upward growth of the vine can be tucked between them without the need for time-consuming tying. The vines should be planted 1.2 m (4 ft) apart and provided with a sturdy bamboo cane to support the first year’s growth.
A vine can be grown quite easily in an unheated greenhouse which is at least 2.4m (8ft) long. You use basically the same method of cultivation as that for a vine on a wall outdoors, except that instead of two rods, you limit the vine to one main stem or rod. The vine must be planted outside the greenhouse, to allow its roots room to develop, and the rod led through a hole at the opposite end to the door, after a portion of the glass has been removed.
Leave the grapes on the vines until they are completely ripe. Then cut them from the vine with secateurs.
Pests and diseases
Birds (use netting), mildew (cut out severely infected shoots in autumn; spray throughout the season with a systemic fungicide and keep the greenhouse well ventilated) and scale insects.