The most important consideration when planting grapes is the location. Grapes need sunshine, as much of it as possible, to create the sugar content needed for wine. Grapes for wine making need more sugar than grapes for eating so they need more ripening in the sunshine. The sugars from the grapes are transformed into alcohol by fermentation so the quality of the wine is dependant most of all on the quality of the grapes that produce it.
The planting area must be well drained as vines do not like to sit in wet ground. The soil doesn’t need to be well composted though as a nutrient poor soil is better suited to producing the smaller, sweeter grapes needed for wine. Only if the soil is too poor to grow weeds will it need some extra fertilizer. Try to arrange the vines so that each side gets the same amount of sunshine. The time spent planning your vineyard before grape planting will pay dividends in the long run.
After selecting a location you might like to have the soil tested and choose a variety suited to it. The cost of professional advice here is a sound investment.
Once you have chosen and prepared your site, and selected the variety, plant the vines far enough apart for that variety. Each variety has a different growth rate, or vigor, and it is this that will determine how far apart the vines should be. You will also need a trellis as vines do not support their own weight. The type of trellis you choose will depend on the variety you’re growing. The European grapes tend to grow upwards and a low trellis is used, while the hybrids tend to grow downwards and a higher trellis accommodates this tendency with bunches close to the ground at the end of the growing season.
During the first year after planting the grapes, tie the strongest shoot to the trellis with a piece of string or plastic tape that will not constrict the vine as wire might. Clip off any other growth from the roots. When the vine is dormant after the first year, prune the vine back again. As growth begins the next spring select the strongest arms from the upright shoots and tie them loosely to the wire as they grow. These will become the main arms of the vine which will support each year’s new growth and produce.
Check before you harvest the grapes that they are fully ripe. The best way to tell is to use a hydrometer for measuring the specific gravity. It can be bought quite cheaply from a winemaking supplier and will indicate the sugar content of the berries. The specific gravity should ideally be around 1.1, plus or minus about 0.005 before harvesting.
There may be some years between the first grape planting and the first bountiful harvest but once established the maintenance is simple and rewarding. Vines may last many thousands of years so it is worth spending a little extra effort in the first years to make sure they get off to the best start.