The use of grafting rootstocks onto varieties for extra vigour in the summer or disease resistance is becoming more common.
When to graft
- When the diameter of the rootstock and the variety is more than 1.4 mm.
- For the variety or scion this means 15 - 19 days depending on variety and time of the year.
- For the rootstock this will be almost always be 2 - 3 days longer.
- The rootstock should never be thinner than the tops.
- Grafting is very stressful for young plants and asks a lot of the root system.
- It is important to have good water and oxygen levels in the plug.
Climate
- In the grafting area - humidity close to 100% and a temperature of 20 °C minimum.
- The grafting area can be in the glasshouse area or in a plastic tunnel in the greenhouse. It is important that the conditions are as constant as possible.
- The humidity is brought down gradually after grafting to activate the graft in the glasshouse.
- There should be a large day night temperature difference as they are strong vegetative plants to give a generative pulse (around 6 °C difference).
Watering and nutrition
Watering and nutrition before the top of the plant is using the root system or before the graft has taken.
- The roots are not being used by the top of the plant at this time so good drainage in the plug is important.
- The graft should take after 6 to 8 days and then the plants are ready to be transplanted into the cube.
Single headed plants - timing
| Grafted single headed plant |
| Operation |
Amount of days from sowing variety |
| Day of sowing |
day 1 |
|
| Grafting |
day 15 |
(+14) |
| Transplanting |
day 23 |
(+8) |
| Spacing |
day 28 |
(+5) |
| Delivery |
day 48 |
(+20) |
Pinched plants - timing (at second true leaf)
- Plant need to be grown more vegetative than a single headed plant.
- In the glasshouse they can grow with a small or no night time drop to get this vegetative pulse.
| Grafted pinched plant (on second true leaf) |
| Operation |
Amount of days from sowing variety |
| Day of sowing |
day 1 |
|
| Grafting |
day 16 |
(+15) |
| Transplanting |
day 24 |
(+8) |
| Pinching |
day 31 |
(+7) |
| Spacing |
day 34 |
(+3) |
| Delivery |
day 54 |
(+20) |
Pinched plants - timing (at the cotyledons)
- Pinched plants at the cotyledons are more vegetative than plants pinched on the second true leaf but less vegetative than single headed plants.
- Care must be taken when pinching on the cotyledons in low light conditions as development of even shoots can be quite difficult.
| Grafted pinched plant (on cotyledons) |
| Operation |
Amount of days from sowing variety |
| Day of sowing |
day 1 |
|
| Grafting |
day 15 |
(+14) |
| Pinching |
day 23 |
(+8) |
| Transplanting |
day 31 |
(+8) |
| Spacing |
day 38 |
(+7) |
| Delivery |
day 58 |
(+20) |