Caring for Grapevines and Pruning Vines

Caring for Grapevines and Pruning

Grapes are one of the best fruits to grow in a greenhouse or conservatory where they are less subject to rot, frosts and bird damage. They can be planted inside, but outside gives them a bigger root run with more moisture to draw on and leaves the inside floor area clear for other plants. Bring the vine inside through a hole, make sure the hole can be enlarged as the stem grows and insulate the outside stem.

Caring for Grapevines and Pruning It is considerably advantageous to grow vines in large containers, with the roots confined, because this reduces the pruning and allows for many varieties in the space taken by just one vine growing unhindered. Heat is used under cover so that the vines can be started into growth sooner. Then grapes can be had for midsummer or earlier, and some of the more tender and luscious, but long-season old varieties, such as ‘Madresfield Court’ and ‘Muscat of Alexandria’, can be grown.

Less heat is used if you take the vines outdoors after they have fruited to ripen and harden the wood in the late autumn. Prune them once the frosts have come and leave them out until late winter or early spring, when bringing them under barely heated cover will start them into growth. If it’s frost-free they will crop much earlier. Once under cover, be careful not to let them get a chill or draught as the sudden change can precipitate mildew attacks.

Prune hard. Grapes fruit best on last year’s wood, so in the UK a framework is usually formed along horizontal wires. This is because sap always rises, so if any of the canes are significantly lower than the rest of the vine they will get little sap and not fruit. It is better to fill a high wall with two vines, one for the lower tiers and one for the higher than to try and cover it with only one plant.

A year after planting, cut back really hard to three buds to get only one or two strong regrowths; these should grow up to the level of the wires. In late autumn, cut these back well below the wires; their regrowth in the third year can then be trained up to and along the wires and eventually trimmed back to make the frame.

Once the frame is made, which must take at least a couple of years, pruning becomes more complicated. Select and cut back the younger growths to form fruiting spurs in good places on this framework. This is best done in a couple of stages. All shoots are trimmed in summer to three or four leaves beyond the flower trusses — except any growths wanted to replace or extend the framework. If no flower truss appears by the sixth leaf stop it anyway, and mark those canes for later removal and do not use these for next year’s spurs if alternatives are available! Any later regrowths are also cut back to prevent congestion and to re-direct energy to the ripening fruit.

Then, in winter, every surplus bit of wood is removed, leaving well-placed spurs tipped with one small piece of young wood with a bud or two. All else is removed, except where needed to extend or replace the framework. Occasionally a strong young shoot from lower down can be used to replace ugly, worn out spurs or a whole limb of the frame.

In pots, grapevines are pruned even harder to a stump with only a couple of shoots with a couple of buds on each. Ideally four or five equal and fruiting shoots emerge to be tied together at shoulder height and later trimmed not far above. These are then cut back to a bud or two apiece in winter. Be bold, you can rarely over prune grapevines if you leave some firm, well-ripened, medium-sized young wood. Especially under cover, thin the fruit bunches down to a reasonable number if you want size and quality and to keep the vine from exhaustion. The vine will set plenty, so remove three out of four bunches in a good year! In a pot three or four bunches is more than ample.

Make sure grapevines, especially those in pots, never run out of water because if they slow down and restart growth, the berries will split.

Vines suffer from many common pests and diseases and the usual remedies apply to these.


Epicurean attentions

In my dry, frost-free greenhouse ‘Golden Chasselas’ ripens the first berries in midsummer and still carries slightly wrinkled, but eatable, fruits into the New Year. I’ve found spraying my ripe grape bunches with neat high proof vodka cleans them of mealy bugs and other pests without damaging the appearance or quality.

06. January 2011 by admin
Categories: Fruit Gardening | Tags: , , | Leave a comment

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