Establishing A Grape Vine In A Greenhouse.

Traditionally in the UK grape vines have been grown in greenhouses with the vine being trained along the roof ridge inside the greenhouse. This is an effective use of space and also has the added benefit of acting as natural greenhouse shading in the summer plus the grape also helps to maintain the humidity in the greenhouse in the hottest part of the day.

To start a grape for a greenhouse they are best grown in the soil outside the greenhouse at one end and the main stem trained inside through the greenhouse wall or by removing part of a pane of glass. Then the main stem is trained up into the roof where it can be trained along a wire running along the inside roof ridge.

Without doubt one of the most important keys to growing grapes both outside and in a greenhouse is to prepare the soil properly before planting, vines naturally grow on forest floors and so tend to do better in soils that are open and contain a high amount of organic matter. The organic matter is very important in the case of a grape because it helps supply an even amount of moisture to the plant as the grapes form and so avoids the splitting of the grapes which can often occur in sandy or heavy clay soils that are lacking in organic matter

So when planting dig a large hole lightly fork the sides and the base to break up any compaction and then mix some well rotted farmyard manure or garden compost into the soil that is going to be back filled around the vines roots as its planted. Then when the vine is planted add some of the organic matter as a mulch around the stem.

With a young vine its important not to overfeed it in the first few years and to allow it to establish at its own pace. Ideally you need to be adding a handful of Growmore fertilizer around the vine in the late winter and liquid feeding with liquid tomato feed two or three times during the spring.

As the main stem grows along its training wires in the inside ridge of the greenhouse its best tied in with small tree or standard rose ties which will support the weight when it starts to crop later. Once the main stem has grown to the required length you can prune the end, this will have the effect of encouraging more side shoots to form which in turn will create fruiting spurs similar to the spurs seen on fruit trees

Varieties to consider

Muscat Hamburg’: An early season black dessert grape with good flavour; performs well in an unheated greenhouse; needs assistance with pollination.

Black Hamburg: Also known as ‘Schiava Grossa’; a reliable black grape with excellent flavour; performs well in an unheated greenhouse; skins may break and rot if allowed to hang on the vine too long after ripening.

‘Chasselas’: A small white early-season grape that performs well in pots with a sweet flavour.