Grapevines are grafted to:

• Confer resistance to Phylloxera or nematodes
• Match the plant roots to soil conditions
• Influence scion vigour
• Change varieties in an established vineyard (top-grafting)<.li>

Field grafting

This is the traditional practice where the rootstocks are planted in the vineyard first, then top grafted

Bench grafting

This is carried out indoors during the late winter/early spring;

• Prior to grafting, the cuttings are stored in damp sawdust, and then soaked for 24 – 48 hours before the operation to make them less brittle.
• Cut rootstocks to 24 – 36 cm lengths with the lower cut immediately below a node
• Remove all buds, and align them in order of the diameter of the top
• Scions cut to one-node lengths with 2 cm above the node and 5 – 6 cm below.
• Align them above the rootstocks according to the diameter of the base
• Graft, either by hand (whip technique), or by machine (omega technique)
• Dip top in molten paraffin wax up to just below graft union
• Store in crates, containing sand or sawdust.
• Maintain humidity at 90% (but with good drainage) and temperature between 21 - 29ºC for 3 – 5 weeks.
• Once callusing is complete, remove grafted cuttings and trim off any roots from the scion or shoots from the rootstock.
• Re-dip in molten paraffin wax
• Transfer to cold store (1 - 4ºC) or plant into pots and keep at 18 - 21ºC for 7 – 10 days then move to temperate greenhouse.

Grafted rooted cuttings are either sold as bare cuttings that have spent one season in a vine nursery after grafting, or as potted plants that have been ‘forced’ in a greenhouse, and so can be planted out within 10 months of grafting.

Top-grafting

These techniques can be used to change cultivars in an established vineyard.

Cleft grafting

Usually carried out on vines less than 15 years old with trunk diameters 2 – 6 cm.

• Just before budburst, saw trunk 3 cm above graft union
• Split the trunk to a depth of 3 – 5 cm across its widest point.
• Insert two wedge-shaped two-bud scions into the slit, ensuring that the cambium layers match
• Tie up tightly with raffia
• Cover the graft, either with soil, or with a rigid plastic sleeve filled with sand, and keep covered until callusing is complete (1 season)
• Keep graft well-watered, but allow excess water to drain away
• Tie shoots carefully to supporting stake

Cleft grafting can have a good success rate (60 % minimum), with 2/3 of normal harvest expected the following year.

Bud grafting

This is now more common, as it has a higher success rate. Both methods require scion cuttings to be collected in the winter and stored at 1 – 4ºC, 90% humidity.
The two methods most commonly used are chip-budding and T-budding. These two methods can be used in succession in order to ensure success. Note that aftercare of plants is very important:

• Protect from drought stress and weed competition
• Remove all suckers
• Support rapidly-growing (tender) new shoots effectively

Bud grafting works well in warm climates, but is difficult to achieve success with in the UK.