How to grow grapes

Grapevines are available in garden centres and from many online gardening retailers. For the widest choice of varieties, and the best advice on which will suit your location, go to specialist fruit suppliers. Grapevines are often sold as grafted plants, but rooted cuttings are also available. If you intend to plant a large number of plants, to start a small vineyard for example, buy vines grafted on a rootstock best suited to your soil type – seek advice from a specialist nursery.

Vines are sold as young plants, usually 30–60cm (1–2ft) tall, either container-grown or bare root (without a pot). Potted plants are available for most of the year, while bare-root vines are only available during the dormant season, from November to March, mainly from mail-order suppliers. Bare-root plants are usually cheaper than potted plants.

If you want to grow a grapevine under glass, it’s best to plant it just outside the greenhouse with its trunk and stems trained inside through a gap near ground level. Vines grown in this way rarely need extra watering and are easier to feed and manage. Vines can also be planted inside, directly into a greenhouse border or in a large container (see below).

When planting inside, the best position is at the far end, so the stems can be trained along the side of the greenhouse, parallel to the roof ridge, running towards the door. One vine is plenty for a small greenhouse – if planting more in a larger greenhouse, allow 1m (3¼ft) between each one.

Water newly planted grapevines during dry spells in their first growing season to help them settle in. Grapevines planted inside a greenhouse need more frequent watering than those with their roots outside, as do vines growing in containers, which can dry out rapidly in warm weather. Vines planted at the foot of a wall may be sheltered from rain, so may need extra watering too.

With outdoor vines, apply a mulch of garden compost or well-rotted manure in late winter to suppress weeds and help to hold moisture in the soil. Apply when the soil is moist, in a layer 5–7.5cm (2–3in) deep. With a greenhouse vine, mulch the rooting area just before growth starts in spring. 

To encourage fruiting, feed grapevines in early spring with a high potassium general fertiliser, such as Vitax Q4 or blood, fish and bonemeal. Scatter half a handful per square metre/yard around the base.

With greenhouse vines and those in containers, start feeding a month after growth starts in spring, using a high potassium liquid fertiliser, such as tomato feed, every two to three weeks. This may also be beneficial for outdoor vines too, particularly dessert varieties. Once the vine is in full leaf, increase feeding to weekly. Stop feeding when the grapes start to ripen and colour up, as extra feeding at this time may spoil their flavour. 

With newly planted grapevines, for the first two years after planting, remove all the flowers so the plant’s energy goes into getting well established. Then, in the third year, allow only three bunches of grapes to grow, and in the fourth year allow about five – or slightly more if the plant is growing well. After that, the vine should be well established and can crop fully. 

You can improve the size, sweetness and quality of grapes by reducing the number of bunches on each stem, and even the number of grapes per bunch. The ideal amount of bunches per plant depends on the age of the vine and the training system you use – see our guide to pruning and training grapes. Reducing the number of grapes in a bunch encourages even ripening and improves air circulation, which reduces fungal diseases. But it’s a fiddly job, so is usually only worth doing on dessert greenhouse vines. Use vine scissors, which have long, narrow blades, or nail scissors, and carefully snip off about one in three grapes per bunch. Afterwards, check the bunches two or three times a week and remove any grapes that are diseased or damaged. 

If you thin out dense bunches, the remaining grapes should develop and ripen better

Ventilation and temperature 

Grapevines like well-ventilated, warm, dry conditions, to deter fungal diseases and improve pollination. So keep the vents open in summer and autumn, especially around flowering and fruiting time.

Some varieties, such as ‘Muscat of Alexandria’, benefit from extra heat, so for these place a small fan heater in the greenhouse in spring (to aid growth) and in autumn (to aid fruit ripening). In September, gradually remove the leaves to expose the branches to sunlight and improve air circulation. In winter, don’t heat the greenhouse and ventilate it freely in still, cold, dry weather until early spring, as dessert grapes need a period of cold to induce dormancy. 

Improving pollination

Greenhouse vines may need help with pollination. During flowering, at about midday on a sunny day when the atmosphere is dry and the greenhouse is well ventilated, either shake the stems briskly but firmly, or stroke a cupped hand over each bunch of flowers, to transfer pollen between them. The latter is a more reliable method for early season Muscat-type grapes, where pollination can be temperamental.

Removing tendrils

Consider removing the tendrils of indoor vines as soon as they appear, as they tend to get tangled up with the fruits and they help shoots to scramble off in wayward directions, making pruning and training more fiddly.

Grapevines can be grown from hardwood cuttings taken in late autumn or winter. Softwood and semi-ripe cuttings can also be taken from late spring to mid-summer. While it is also possible to grow grapevines from pips, it’s a slow process and the resulting plant is likely to produce lower quality fruit than its parents. Commercially, grapevines are often propagated by whip-and-tongue grafting on a rootstock.