Your own grapevine on the house wall is a piece of the south in the garden. Whoever reaches through the leaves in September and picks a sun-warm, sweet grape understands at once why the vine has been cultivated for millennia. And the best part: table grapes, that is grapes for nibbling, thrive today even north of the classic wine regions if you choose site and variety correctly.
For a long time the vine was considered tricky, because without regular spraying it succumbed to the fungal diseases powdery and downy mildew. That has changed. Modern PIWI varieties make growing in the home garden possible without chemicals for the first time. This article shows you how to find the right variety and the right spot, and how the vine pruning succeeds, without which nothing works.
Why PIWI varieties make the difference
The classic table grapes from the shop are mostly prone to fungal diseases. In the damp central European climate that means: without several sprayings per season you lose foliage and harvest to mildew. For a nibble garden from which children are simply to pick a grape, that is no option.
PIWI stands for fungus-resistant (in German, pilzwiderstandsfähig). These varieties are crosses of European noble vine and robust wild vines that bring the disease resistance without losing the flavour. Proven fungus-resistant table grapes are ‚Muscat bleu' with blue, muscat-like berries, ‚Palatina' with yellow, honey-sweet grapes, the near-seedless ‚Lakemont' and the early ‚Birstaler Muskat'. They all get by with much less or no plant protection at all.
Choose by ripening time and site. The cooler and more northerly your garden, the earlier the variety should ripen so the grapes mature before the autumn rains. On a very warm south wall in a mild wine-growing climate, later varieties succeed too.
The right site
The vine is a sun plant. It wants the warmest, sunniest spot in the garden, classically a south or west wall that stores warmth by day and releases it by night. This wall warmth is often the decisive difference that lets a grape ripen or not. A trellis with some gap to the wall ensures air circulates and the foliage dries quickly after rain, which prevents fungal attack.
The soil should be free-draining and humus-rich, waterlogging the vine cannot tolerate at all. Vines root deeply and therefore cope well with drought once established. More important than rich soil is the warmth: better a poor, warm spot than a rich, cold one. No table grape belongs in front of a cold north wall.
Vine pruning: without it only foliage
Vine pruning is the one thing on which grape growing stands or falls. Whoever does not prune gets a rampant wall of foliage without notable yield, because the vine puts all its strength into leaves instead of fruit. The reason lies in the biology: the grape forms on the one-year-old shoots that grow from the previous year's one-year-old wood. The aim of the cut is to renew exactly this fruit-bearing wood deliberately every year.
The best time is late winter, weeks 6 to 9. Then the hardest frosts are over, but the sap is not yet rising. If you prune too late, when the vine is already in sap, it bleeds heavily at the cuts and loses strength. That rarely harms the plant seriously, but is unsightly and unnecessary.
Identify last year's wood
Find the one-year-old shoots that grew last year, mostly smooth and light brown. On them the vine will bear in the coming year.
Cut back to a few buds
Shorten the fruit-bearing shoots hard, depending on the training system to two to six buds. From each bud a new fruiting shoot grows.
Remove old and weak wood
Cut out spent, woody and thin, weak wood entirely. The vine should stay clear, not become an impenetrable thicket.
Build the framework
Tie a strong main shoot horizontally to the trellis. From it the vertical fruiting shoots grow, that is the basic form of most training systems.
Remove side shoots in summer
In summer remove the side shoots from the leaf axils and thin dense foliage around the grapes. More sun and air on the berries means sweeter fruit and less fungus.
Summer care and harvest
The winter cut is not the end of it. In summer the leaf work decides quality and health. Side shoots that grow from the leaf axils cost strength and thicken the foliage, remove them regularly. Around the grapes you thin the leaves so sun reaches the berries and they dry quickly after rain. These handgrips are the best plant protection there is, and with PIWI varieties often the only one you need.
Harvest when the grapes are truly ripe. Unlike apples, grapes do not ripen after picking. The sugar rises only as long as the berry hangs on the vine. So taste, instead of judging only by colour: only when the berries taste sweet and aromatic is the grape ripe. With most varieties that is the case from September to October.
A fungus-resistant PIWI variety on the warmest wall, an annual vine cut in late winter, remove side shoots and thin in summer. Then sweet nibble-grapes ripen even here without spraying.
The core rule for the table grape
Frequently asked questions
Which table grapes are fungus-resistant and hardy?
Proven fungus-resistant (PIWI) table grapes are ‚Muscat bleu', ‚Palatina', ‚Lakemont' and ‚Birstaler Muskat'. They get by with little or no plant protection and are sufficiently hardy, on a sheltered south wall even in rougher locations.
Why does my grapevine bear no grapes?
Usually the vine cut is missing. Without an annual cut the vine forms only foliage instead of fruit, because it bears on the new shoots from one-year-old wood. A too shady, cold site or a still too young plant can also be the reason. Vines usually bear only from the third to fourth year.
When do you prune grapevines?
In late winter, weeks 6 to 9, when the hardest frosts are over but the sap is not yet rising. If you prune too late, the vine bleeds heavily at the cuts. In summer the leaf work follows with removing side shoots and thinning.
Does a table grape need a south wall?
Ideal is a warm south or west wall, because the stored wall warmth promotes ripening. In mild wine-growing areas it works free-standing on a trellis too. In cool, northern gardens the warm wall is often decisive for sweet grapes.
Do you have to spray table grapes?
Classic varieties yes, modern PIWI varieties as a rule not. Their fungal resistance makes spraying unnecessary. Supportively, an airy site and consistent thinning of the foliage help, so the leaves dry quickly after rain.
