The grapevines are growing well and looking beautiful. Everything that you see above ground on the vines is considered part of the canopy. As you can tell in the photo, it is getting quite large! That means that it is time to think about managing it. For us, canopy management in the vineyard and raising wires go hand in hand. A large healthy canopy is always a good sign of a healthy vineyard. With the projected crop loss from the hail damage, the vines have certainly surprised us this year. God has been merciful in allowing the vines to bounce back. After that hailstorm, the vineyard looked prrreeety sad! While we will not have a full crop, the current estimate is way more that what we thought after the hail!
Why is the canopy so important? The canopy is responsible for photosynthesis, transpiration (water movement through the plant and the evaporation of it through the leaves), and directly affects the grape ripening. So, you can see that canopy management in the vineyard is a very important aspect of vineyard work.
We use a Vertical Shoot Positioning (VSP) trellis system. Ideally, the shoots of the grapevines should grow upward exposing as many leaves as possible to the sunshine. We have a cordon wire at 3 - 4 feet off the ground that runs horizontal to the ground. This wire supports the main arms of the vine and from these arms the shoots grow upward. Two additional wires on both sides of the vine foliage, at 4 ft and 6 ft. from the ground, are used to hold the shoots as vertical as possible, hence, VSP. So, once the shoots are raised with the VSP wires, the shoot's tendrils attach to the wires which gives more support.
We used to raise wires by hand which took most of our time in the summer. But in 2014, we purchased the wire lifter that attaches to our Pellenc 4560 multi-function vineyard machine. In the photo below, vine shoots are being lifted in front of the machine as it lifts the wire to the desired height (seen in the middle right of the picture) and stands up the shoots by the rotating black wheel (bottom half seen in the middle). Plastic clips are periodically snapped on to the two wires (one on each side) to keep it all together using the stapler mechanism of the wire lifter. Below you can see a row of Roussanne before the wire raising. The shoots are sprawling and some are even close to touching the ground. Here is the same row after lifting the wires with the Pellenc 4560. Here is another photo showing the same row with the row next to it which has not yet been raised - what a difference! You can see how the shoots are now going upward, the vine row is opened up allowing more sunlight to hit the growing zone for the grapes. Looking closer, you can now see the grapes that were hidden before by the canopy. Mechanization is a wonderful thing! I am all for working smarter - NOT harder!