Prune greenhouse grapevines

It’ll keep them fruiting and restrict them to a manageable size

Grape vines are pruned twice a year to keep them fruiting and to a manageable size. Summer pruning is mainly to shorten long growths to divert energy to developing grapes and to prevent them growing too large in a greenhouse. In the winter months, when the vine is dormant, we carry out the main prune to remove this season’s growth back to the permanent framework of stems, known as rods. In a cold, unheated greenhouse pruning can be done anytime up to early February before the saps start to rise. In a heated, frost-free greenhouse you’ll need to prune a li le earlier and I aim to do it by early January, because in frostfree conditions sap starts to flow much earlier. If you prune when the sap is rising, the cut will weep, which isn’t good for the vine.

When pruning, simply cut back all this year’s growth to one or two buds from where it grew. Over a few years, this develops a series of short spurs along the main rods, from where new growth will emerge in spring. It’s also a good idea to scrape off as much of the old, peeling bark from the main rods as possible, as this is a perfect hiding place for pests such as aphids and scale insects.