Guide to Growing Grapes – How to Grow Grapes
Guide to Growing Grapes – How to Grow Grapes
Grape vines can be grown outdoors, trained against sunny walls or over trellis, or wires, or under glass in heated or unheated glasshouses. Outdoors, ripening tends to be uncertain and selection is limited to certain very hardy varieties.
Vines need good, richand good . Greenhouse borders specially prepared for them should be at least 3ft deep and the full width of the house. Hard rubble should be placed in the bottom for drainage, a layer of turves on top of this and then the border should be filled with good loamy soil, well sprinkled with wood ashes and coarse bonemeal, and with a little well-rotted manure all thoroughly mixed in.
Vines are best planted in late February or early March, and the roots should be well spread out and made thoroughly firm. Either one vine can be trained to fill a whole house with numerous stems or else — the more usual method — each vine can be restricted to one main rod, when the vines should be 5 to 6ft. apart. The first year the newly planted vine is only allowed to make one main growth and this is trained upwards towards the ridge of the house for single rod cultivation or horizontally along the eaves for multiple-stem cultivation.
In subsequent years side growths are allowed to form every 15 to 18in. on each side of each main rod of single-stem vines. Multiple-rod vines are permitted to form a main growth every 5ft. along the horizontally-trained stems and these are trained to the ridge, each being subsequently treated like the main rod of a single-stem vine.
The side growths carry the and bunches of grapes, not more than one to each side growth which is stopped two leaves beyond the flower cluster or when it is 2 to 3ft. Long. All secondary growths which appear are stopped at the first leaf. All these side growths are carefully tied to wires strained horizontally about 9in. below the glass.
Each winter the side growths are cut back to within one or two dormant growth buds of the main rods or the woody ‘spurs’ which in time form on them. In January the main rods are untied and allowed to hang down to check the uprush of sap but, when growth has started, are re-tied in their former positions. Allow only one side growth to form at each spur and rub off any others. Vines respond to fairly generous feeding. In winter the top 2in. of soil can be carefully removed and replaced by a mixture of equal parts well-rotted manure, and good, loamy soil. Immediately after flowering the border can be further enriched by a top dressing of a well-balanced general fertiliser at the rate recommended by the manufacturer.
Vines are started into growth at any time from January to March by closing the ventilators and allowing the temperature to rise to 10 to 16°C. (50 to 60° F.). The border should be thoroughly soaked at this time. Daily syringing with clear water is necessary now but should be discontinued while the vines are in flower, when the temperature may rise a little and the atmosphere be kept dry.
Most grapes are self-fertile and good sets of berries are usually obtained under glass without outside help. Some gardeners like to further aid pollination, however, by tapping the rods sharply at about mid-day during this period to further distribute the pollen. Outdoors, pollination should be done with a camel hair brush.
In June, when the berries are well formed, they must be carefully thinned with narrow, pointed scissors. The smaller seedless berries are cut out first and then the remainder of the surplus berries can be removed. To avoid touching the berries a small forked stick is useful. It is best to start at the bottom of the bunch and gradually work upwards.
Water is necessary to keep the soil moist, and keep the paths and walls damp to maintain a fairly humid atmosphere, but allow the air to become much drier and the temperature to rise a little as the grapes ripen.
Out of doors, vines can be treated in much the same way as those indoors, but it is best to plant them against a warm and sheltered wall.
Increase by taking ‘eyes’, or dor mant growth buds, cut from well-ripened side growths in autumn with a short piece of stem attached. These ‘eyes’ are laid horizontally, but uppermost, in John Innes No. 1 Potting Compost in small flower pots, one per pot, and are started into growth in a propagating frame with a temperature of 16°C (60° F).
These include :—
Under glass: Black Hamburgh, Madresfield Court, and Muscat of Alexandria; the fruits of the last-mentioned are not black as are all the others, but yellow.
For warm, sunny walls outdoors: Buckland Sweetwater and Royal Muscadine are white grapes which ripen early. Brandt is an early-maturing black grape and the leaves sometimes have attractive autumn colour.