Can I grow grapes outdoors in the UK?

Which grapes actually ripen outdoors in Britain, the south wall that makes the difference, and the bunch thinning and leaf removal that turn a mass of small sour berries into fruit worth eating.

Difficulty: intermediate
Time: 2 hr
Read: 4 min

Short answer

Yes, in most of England and Wales, on a sunny sheltered south or south-west wall, with an outdoor-suitable variety. The critical jobs are thinning the bunches to one or two per shoot, stopping shoots two leaves beyond the last bunch, removing leaves shading the fruit in late summer, and accepting that a cool wet August ends the season regardless.

Grapes are grown outdoors across Britain far more successfully than most gardeners expect, but the margin is thin and the variety choice matters enormously. A dessert variety bred for a heated greenhouse will not ripen in a Yorkshire garden. An outdoor variety on a warm south wall in the Midlands will produce a real crop most years, and in the far south will do it reliably.

What you'll need

An outdoor grape variety
A sunny sheltered wall or fence with wires
Secateurs
Long-nosed scissors for thinning bunches (optional)
Netting for the ripening period (optional)

Step by step

Choose an outdoor variety, not a greenhouse one.For eating: Boskoop Glory, Phoenix, Regent, Lakemont and Flame are all grown successfully outdoors in the UK. For wine: Solaris, Rondo, Bacchus and Seyval Blanc. Greenhouse dessert varieties such as Black Hamburgh will not ripen outdoors reliably.
Give it the best wall you have.South or south-west facing, sheltered from wind, with as much reflected heat as possible. The wall is doing the work of a warmer climate and it is not optional in most of Britain.
Plant into free-draining soil, not enriched ground.Vines want a well-drained, rather poor soil and hate waterlogging. Plant about 30cm out from the wall so the roots are not in the dry rain shadow, and do not dig manure into the hole.
Put up wires and train it as a rod with spurs.Horizontal wires 30cm apart on vine eyes. A single permanent vertical rod with fruiting spurs along it is the simplest system for a wall, and the pruning follows from that.
Restrict the crop hard.Allow one bunch per fruiting shoot on a young vine, one or two on an established one. A vine left to carry everything it sets produces a great many small sour grapes and ripens none of them.
Stop each fruiting shoot two leaves beyond the last bunch.In early summer. It sends the vine's energy into the fruit rather than into more shoot, and it keeps the plant manageable.
Thin the berries within each bunch on dessert grapes.With long-nosed scissors, remove roughly a third of the berries when they are pea-sized, working from the inside of the bunch. It gives larger berries and much better airflow, which is the main defence against botrytis.
Remove leaves shading the bunches in late summer.From about August, take off the leaves directly shading each bunch so sun reaches the fruit. Do not strip the vine — it needs its leaves — just clear the fruit.
Watch for mildew and botrytis.Powdery mildew shows as a white dusty coating on leaves and fruit and is worse in still humid conditions; botrytis rots the bunches in a wet season. Airflow, bunch thinning and leaf removal do most of the control available in a garden.
Net the bunches as they colour.Birds and wasps both take grapes. Fine netting, or individual bunch bags on a small vine, from the point colour starts.
Taste rather than watch the calendar.Grapes do not sweeten after picking. Leave them as long as the weather allows and pick when they actually taste sweet, usually September into October.

Tips

A greenhouse or conservatory changes everything: the vine is planted outside and the rod trained in through a low vent, and a much wider range of varieties then ripens.
Wine varieties ripen at lower sugar levels than dessert varieties and are considerably more reliable in a cool summer.
Vines are extremely long-lived and take three or four years to start cropping properly. The first two years are about building the rod, not getting fruit.
Do not feed heavily with nitrogen. A vine that grows too vigorously makes leaf and shoot at the expense of ripening fruit.
Wasps find grapes reliably. Bunch bags of fine mesh are the practical answer on a garden vine.

Common mistakes

Buying a greenhouse variety for an outdoor wall — It will grow enthusiastically and never ripen. Variety choice is the single most important decision in outdoor grape growing in Britain.
Letting the vine carry every bunch it sets — A vine will set far more than it can ripen. Restricting to one or two bunches per shoot is what produces edible grapes rather than sour ones.
Planting in rich, moisture-retentive ground — Vines want free drainage and moderate fertility. Rich soil gives vigorous growth and poor fruit.
Stripping all the leaves to let the sun in — The leaves make the sugar. Remove only those directly shading the bunches, and only from late summer.

Questions people ask

Which grape varieties grow outdoors in the UK?

For dessert grapes, Boskoop Glory, Phoenix, Regent and Flame do well. For wine, Solaris, Rondo, Bacchus and Seyval Blanc. Avoid greenhouse varieties such as Black Hamburgh outdoors.

Do grapes ripen after picking?

No. Unlike pears, grapes do not sweeten off the vine. Leave them on as long as the weather allows and pick by taste.

Why are my grapes small and sour?

Almost always too many bunches on the vine, not enough sun, or a variety that was never going to ripen outdoors here. Thin to one or two bunches per shoot and check the variety.

Do I need a greenhouse for grapes?

Not in most of England and Wales for outdoor varieties on a sunny wall. A greenhouse widens the choice of varieties considerably and makes ripening reliable further north.