Grapes have been cultivated by humans for at least 5000 years and are used to produce raisins, vinegar and wine. They are mainly grown by the home orchardist for delicious, fresh eating, Table or Dessert Grapes. The 2 species grown are known botanically as Vitis vinifera from Europe and Vitis labrusca from North America.
Grapes are highly ornamental as well as productive and if grown in the right conditions they will be relatively pest and disease free. In wet humid conditions grapes are susceptible to a fungal disease called Botrytis. This is not always seen as a negative thing as Botrytis, AKA ‘Noble Rot’ causes the grapes to have highly concentrated sugar levels. These grapes are used to produce delicious dessert wines. Being a tendril climbing plant your Grape vine will need a good support system such as a fence, trellis or pergola so make sure you have that sorted prior to planting.
Grapes grow best in a warm, sunny, sheltered position; they are best suited to areas that are not too wet. Grapes, when dormant in winter are tolerant of frost and winter cold. However in spring the emerging buds can be easily damaged even by light frost so choose your planting position with this in mind.
Grapes are tolerant of most soil types except very heavy soils – such as sticky clay. Free draining soil is best as Grape plants have a root system that needs to burrow deeply into the soil.
As with most fruit crops it is important that the vine does not completely dry out during the summer growing season when the fruit is developing. However a dry period is acceptable or even preferred just prior to harvest as this helps the fruit produce maximum sugar levels.
In any reasonable soil Grapes seldom need extra feeding. It is important that Grapes do not get an over abundance of nutrients especially Nitrogen so if you are tempted to apply fertilizer use the “less is more” philosophy.
Be aware that Grapes are sensitive to soil and climate – more so than many other fruit, this can affect the sugar levels and therefore the flavour of the crop. This is why you get a regional difference in the taste of varietal wine. Grapes are wind pollinated or self pollinated and do not need a pollination partner. Sometimes heavy rain fall can affect pollination as it prevents the pollen spores from drifting naturally.
The main pruning of Grapes is done in early winter. If you prune heavily in the spring you will find that the cuts will continuously ‘weep’ – as with most weeping this is not a good thing! In the home orchard the usual method of pruning is called Spur Pruning. After planting in winter reduce the stem to down to two buds. The spring growth that is produced from this cut is trained upwards to start forming the trunk. In the second winter prune this main stem back to the required height of the trunk and train one or two side growths (laterals) horizontally to form a fruiting arm. The following season’s growth will see shoots growing upwards from the fruiting arm. In the third winter these shoots should be spaced 15cm-20cm apart, cut out anything in-between and cut back the remaining upward shoots to two or three buds. This sequence is followed for each season thereafter. These buds develop into your main fruiting spurs and will become large and quite knobbly.
In summer wayward lateral growth can be snipped off just beyond a developing bunch of grapes. Leaves that are shading developing bunches can also be clipped away. If the vine looks over laden with bunches some of these can be thinned out but this is not absolutely necessary.
Depending on the variety planted Grapes are usually ripe from February through to May. Grapes do not ripen after harvesting so they should remain on the vine until sweet enough to eat. You may have to protect them from greedy birds that have a taste for ‘Vin du Jour’. Clip bunches off with sharp clean secateurs try our ARS Secateurs - V8Z or specially designed Fruit Pruners ARS SE-45. Enjoy!
Wairere Nursery 826 Gordonton Road, R D 1, Hamilton Ph: (07) 824 3430 Email: Open 7 days 8:30am-5pm