Green Man Publishing

Grape

(Vitis vinifera)

This is the European grape and produces the best flavored fruit for fresh eating (it includes the best seedless varieties), wines and raisins. For garden use you will probably want to concentrate on table grapes (and maybe raisins). Wine grapes are easy enough to grow but making good wine out of them is much more difficult.)

European grapes are by far the most useful and important grape species, but they require fairly specific growing conditions and are not very hardy. They grow best in the less humid western states and are limited in where they will grow well, by their susceptibility to pest and disease and requirement for heat. If you live in an area where they don’t do well (a large part of the country) you may want to try growing native American grapes. These are much more adaptable and can be grown in a wider range of climates See below for more on these.

History: Grapes and wine have been an integral part of western civilization for over 5000 years.

About Grapes

Hours of winter chill: 100-500

Size: A single vine can get very big (up to 100ft), but usually pruned to 12-15ft

Zone: 6-10

Blooming period: Late spring

Fruiting period: September – October

Life expectancy:

Bearing age: 2-3 years

Yield: 20-50lb

Days to harvest:

Spacing: 6-8ft apart

Ease of growing: Grapes are ideal for the anally retentive gardener because you can lavish all kinds of attention on them. However they are actually pretty easy plants to grow and can be quite low maintenance if give them what they need.

Climate: Table grapes need lots of sun and heat to produce the sugar that makes sweet delicious grapes. Wine grapes don’t need so much heat as cooler temperatures produce more complex flavors. Grapes are fairly hardy (to 10°F) but can’t tolerate extreme cold.

The southwest (especially California) is the best place to grow them in North America and even then it is important to select a variety that is adapted to your local climate. Established plants are very drought tolerant, though they produce better if given regular moisture. If your climate is too cold for these types you have your choice of lots of American varieties (See Varieties below).

It is possible to grow grapes in cooler climates by training them against a south facing wall. In even  colder climates you might plant them in a greenhouse and let them go out through the window for the summer.

Soil

pH 5.5 – 8.0

The ideal soil for grapes is deep, moist, well-drained and reasonably fertile (the better the soil the bigger the crop). However they will grow in most soil types, so long as it is well drained (they don’t like wet soil at all).

Site: Grapes need lots of sun to produce sweet fruit, though like most vines they will happily tolerate some shade close to ground level. The site should have good air drainage and circulation to minimize frost and disease. In cooler climates it should also be sheltered from the wind. If your soil isn’t very well drained you might consider planting on a hillside, or on a mound.

Soil preparation: The plants will occupy their site for a long time so take care when preparing the soil.

If the soil isn’t very fertile you should prepare the whole growing area (not just the planting hole) by single digging. or even double digging if the soil is very compacted. This enables you to remove perennial weeds, loosen the soil and incorporate organic matter (compost or aged manure), along with wood ash and maybe some standard fertilizer mix.

Planting: Make a large hole so you can spread out the roots widely. After planting the plants are usually pruned back to leave 2-8 buds.

Maintenance:

Fertilizing: You can tell whether plants are getting enough nutrients by the amount of growth and fruit they make. If they are doing poorly you might give additional fertilizer (use a standard mix) in spring. Don’t fertilize late in the year as it can result in vigorous new growth that is vulnerable to frost. Normally the annual spring mulch application of compost or aged manure should be adequate.

Watering: Grapes are quite drought tolerant, but will be more productive if given regular water. Drip irrigation works best because no water touches the leaves or fruit, which can result in fungus problem. Even if you don’t irrigate them you may want to give an occasional deep watering, or even a single watering when the fruit are starting to size up.

Support: Grape is a vigorous deciduous climbing vine and uses tendrils to cling onto vertical surfaces. The plants can get very heavy when laden with fruit and require a sturdy support system to keep them off the ground.

Training: Grape growing is a serious business and many training methods have been devised (Kniffin, Guyot and more).

Pruning: Grapes are very vigorous and can get quite tall if allowed to. They require serious pruning to keep them in bounds and productive. This is done in winter and is the most important annual task. They bear on the current seasons wood and pruning is basically about cutting back to good buds that will become the following years fruiting vines.

Thinning: This is usually done to improve fruit size, but if you don’t mind smaller grapes it isn’t necessary (especially for seedless types, for drying into rasins or for wine). If necessary the excess flower clusters shouldbe removed in spring (how many depends upon the size of the plant).

Propagation: Grapes are easy to grow from hardwood cuttings in winter. In some circumstances a specific rootstock is required, in which case they are grafted.

Pollination: Most grape varieties are self-fertile, which means you only need to plant one variety. Seedless varieties are not parthenocarpic (producing seed without fertilization), they are actually pollinated but the embryo aborts and doesn’t develop into a seed .

Maintenance: Mostly this means pruning, but often also spraying.

Mulch: Grapes benefit from a mulch, to supply nutrients, suppress weeds and conserve moisture. If you need to supply nutrients apply a 3” mulch of compost or aged manure in spring. If you just want to conserve moisture and suppress weeds then wood chips will work best and last longer.

Pests: Grapes are susceptible to a number of pests, but chances are you won’t encounter them.

Grape berry moth

Japanese beetles

Birds: Love the ripe grapes as much as humans. In extreme cases you may have to net the plants, or you could just enclose whole fruit clusters in paper bags.

Wasps: Enjoy the ripe fruit too. Enclosing fruit clusters in paper bags will foil them.

Disease: Grapes are susceptible to a number of diseases when growing in humid climates. This is why it is so important that they have good air circulation.

Powdery mildew

Anthracnose

Black rot

Harvest: As the fruit ripens it becomes less acid and much sweeter and changes color (even green grapes becomes lighter and more yellowish). However even after they change color they still need several weeks to develop their full sweetness. You can tell when they are ready to harvest by tasting to see how good they are. When fully ripe they are sweet and delicious and any seeds will be hard and brown.

When the whole cluster is ripe it is cut from the vine with secateurs. It is very important to be sure they are ripe because they don’t ripen any further once picked.

Grapes for drying into raisins can be left on the vine longer as their sugar content will increase and they will start to shrivel. Making raisins is a very important use if you have a lot of vines and a long period of dry and sunny weather.

Storage: Fresh grapes don’t keep for very long before they start to ferment naturally (though see keeping in a bottle). They can be dried if you have the right climate and the right variety.

Landscape uses: These attractive, hardy, productive and vigorous vines produce an abundance of foliage every year and have attractive woody trunks too. They are perhaps the single most outstanding food producing vine (Kiwis are their only serious competition). They work as climbers on buildings and fences (or wire trellis), or can be trained to grow overhead on arbors and pergolas. In Greece you commonly see them growing on rooftop arbors, having been trained up from ground level. They also make a good deciduous screen.

Varieties

For success in growing grapes you need to choose a variety that is adapted to your climate.

Cooking

Grape leaves are commonly used in Mediterranean cooking.

Also raisins and grape juice.

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