Prepare your soil to get the biggest growth increase.
The GroGuard is provides ideal conditions for shoot growth.
To allow the vine to take advantage of these conditions, the grower must ensure that conditions below ground are as close to ideal as practicable.
Have your soil assessed by a qualified soil scientist. This will require several to over a hundred backhoe pits depending on the size of the site and its complexity. The report must advise on potential vine root restrictions, how to overcome them and how much gypsum (to improve soil structure) and lime (to raise pH) to apply.
Add correct amounts of gypsum and lime. These two chemicals have completely different roles in the soil do not confuse them. There is no substitute for either chemical. Adding these chemicals later is ineffective they must be applied when the vineyard is ripped. Gypsum cannot be added via irrigation water unless only very small quantities are required. Do not be tempted by shortcuts.
Add as much organic matter as you can. The amount to add is several tens of tons per hectare. Organic matter must be fully rotted. If not, there is a large danger of an outbreak of root rots.
Rip correctly. For detailed information about gypsum and ripping see gypsum and ripping. Do not rip faster than 5 km/h. Soil moisture content at ripping must be dry enough to fracture but not so dry as to make dust. It should fracture into pea sized aggregates. After ripping, the penetration resistance should be below 1 MPa, and preferably around 0.5 MPa.
DO NOT RECOMPACT YOUR SOIL. No wheel traffic should travel the undervine area after planting. Do not work the soil after it is ripped, especially if the soil is moist or wet. Knock posts from well off to the the side. If in doubt, try what you are about to do and see the effect on penetration resistance.
Recheck the penetration resistance prior to planting. It should be less than 1 MPa, and preferably around 0.5 MPa, to a depth of at least 800mm, and at least as wide as 800 mm.