November is the time to prune grapes:
Vines should be pruned once their leaves have fallen and the plants are dormant – if you prune them during the growing season then they will ‘bleed’ or loose sap when they are cut. This is the advice from the Royal Horticultural Society on how to go about it.
The main pruning time is early winter (late November or December). Training and pinching out of new shoots, as well as thinning of fruits, is carried out in spring and summer.
If you are establishing a new grape vine, set up a support system.
Plant the vines during the dormant season from late autumn until late spring (October-March) .Leave 15cm (6in) between the vine and the wall or side of the glasshouse.
After planting, cut back the main stem by two-thirds and cut back any side shoots to one bud. Then follow this advice from the first year:
In the growing season (when the main stem reaches 3m (10ft), or the top of the support):
- Pinch back the side branches to five leaves
- Pinch back the side shoots growing from the side branches to one leaf
- Tie the main stem and side branches to the supporting wires
- Cut back the main stem by two thirds
- Cut back the side branches to one strong bud
In the growing season
- Allow the main stem to continue growing.
- Let two of the side branches produce a bunch of grapes, then pinch back their tips to two leaves beyond the bunch of grapes
- Pinch back side branches not bearing fruit to five leaves
- Reduce the main stem by half, cutting to a bud on mature brown wood
- Cut back side shoots to 2.5cm (1in) or to two strong buds
Year three onwards
- Untie the main stem to one third of its length above ground
- Allow the top two thirds to bend down and almost touch the ground. This encourages side branches to break along the full length of the stem
In the growing season
- As soon as the buds on the spurs (knobbly bits where the main side branches were cut back to a single bud) begin to grow, tie the main stem back into position against its supports
- Pinch out the growing tips of flowering side branches two leaves beyond the flower cluster, allowing only one flower cluster to develop per side branch for dessert grapes. More clusters can be allowed for wine grapes
- Tie in each flowering side branch to a wire
- Pinch out non-flowering side branches to five leaves
- Pinch out any side shoots growing from the side branches to one leaf
- For wine grapes, allow all bunches of grapes to develop. For dessert grapes, allow only one bunch per side branch
- Cut back the side branches to one or two plump buds from the main stem (the ‘rod’ or ‘cordon’
- If you have a vigorous vine that needs to cover a large space, consider training it as a double or multiple cordon as follows:
- Allow the newly planted vine to grow two strong vertical shoots from near its base, removing any weak or excess shoots
- Lay the two selected shoots horizontally to each side of the lowest support wire
- Side branches will grow from the horizontal arms. Select vertical side branches to form the multiple rods or cordons that will make up your structure
- Each rod or cordon is pruned as per the instructions above for rod and spur pruning
- Pinch out excess shoots developing from the two horizontal arms and the tender tips beyond the rods