In this country, grapes are more commonly grown in a greenhouse although with modern breeding practices, there are now a few varieties that can be grown outdoors but these are really only suitable for wine-making.
Soil Conditions and Siting
Grape vines will thrive on a poor soil as long as there is plenty of organic matter in it. The pH of the soil should be around 6.5 – 7.0.
Plant out in autumn or early winter setting the plants 5ft (1.5m) apart. After planting mulch with a well-rotted manure or compost.
Grow outdoor grape vines against a wire and post support. Erect a row of 4ft (1.2m) posts 6ft (2m) apart. Fasten wires at 18" (45cm) intervals. At the central point between two posts erect a 6ft (2m) post. Plant each vine against the 6ft (2m) post.
Mulch annually in the spring with well-rotted manure or compost. If growth seems poor, feed with Blood, fish and bone or Growmore at the rate of 2 handfuls per yard/metre run.
Immediately after planting, cut the main shoot back to 3 strong buds. In the first summer 3 shoots will grow, these should be tied to the stake. In autumn pinch out the tip of the main stem.
In the second winter, tie the two strongest shoots to the bottom wire, training to either side of the stake. Prune each one back to 30" (75cm) and the main stem back to three buds.
In the second summer the main stem will again produce 3 shoots, tie these in to the stake. Pinch back any side shoots that may develop to 3 leaves. Over the summer the shoots that have been tied to the bottom wires will develop side shoots – these will bear fruit and should be tied in vertically to the wires above. Pinch back any shoots that appear from these to 1 leaf. Only allow a maximum of 4 bunches of fruit in the first year. In subsequent years, 1 bunch of fruit per shoot can be grown. Cut out the fruited shoots after harvesting.
The following season, tie two shoots from the central stem to the bottom wires and repeat the above process each year.
Desert grapes will require thinning using nail scissors or special grape-thinning scissors. Remove any berries that are misshapen or diseased, allowing the rest of the fruit to reach pea-size. The bunches will then require the removal of some of the grapes to allow the remaining ones to reach full size. If the grapes are being grown for wine making, no thinning is required.
When the stems turn brown the fruit is ready for picking. This is done by cutting the stem on either side of the bunch to leave a small ‘T’ shaped handle. To store, lay on a tray in a cool, shady place. They will keep in this way for about 1 month.
Netting may be needed as protection against bird damage.
Pests and Diseases
Wasps, Birds, Botrytis, Mildew and Red Spider Mites are common problems. (See pests and diseases section for prevention's and cures. This is accessed via the Main Index Page)
14 December, 2003
© copyright 1999, P. A. Owen