|Adam - Wine Maker|
Out here at the vineyard we have been discussing strategies to reduce vine vigor for a few years now, high levels of vegetative growth are often exhibited in grape vines in the mid-Atlantic region and Cabernet Franc in particular has a tendency to grow very long shoots which can affect the balance of the vine and impact the quality of the grapes. While we have been very successful in the past balancing the vineyard through vine/rootstock selection, hand and mechanical labor, there is always room for improvement and increased efficiency! Lucie, our consultant, has been very interested in trying a strategy of early shoot cutting to slow the vines down and allow smaller shoots to catch up with larger/stronger shoots, in effect balancing the shoots and creating balance between leaf area and crop load, all very important for grape quality and consist ripening.
With the cool spring this year we also had more inconsistent shoot growth than we usually see, some shoots took off and reached the top wire (and beyond) while other shoots were only small. This was a great time to test the strategy.
We determined a length we thought wound be a standard height (2/3 or the way up the trellis) and any shoots that were above the top wire of the trellis we cut at the standard height, any shoots that were shorter than the standard height we left alone. Our interns Brycen, and Timothy, my assistant Johnston and myself performed the work. With one man working in each row we could each cut a row rather quickly.
We performed this operation almost a month ago, the photo below was taken yesterday (6/27) after our second tucking (at which time we also did a little trimming, but not a lot was required).
The benefits of this strategy are very good. The weaker shoots are now at the same level as the shoots that we trimmed, all of the grapes are at the same developmental stage (this is the biggest benefit in my opinion since it has a huge impact on quality), the vine growth has definitely slowed considerably resulting in a canopy that has remained more open (this helps improve disease control and fruit quality by promoting air flow through the canopy and light penetration to the grapes) and has required less physical management, the subsequent vineyard tasks were faster and easier for the crew (particularly tucking). We have yet to use our hedging machine this year, we would have normally completed one pass through the vineyard by this time, so we have also saved fuel and reduced soil compaction by employing this strategy.
There were a couple of consequences, none very major. First, it requires labor at a time when we have so much going on in the vineyard, all of which requires hand labor but the practice went pretty quickly and actually saved time later (now)! Second, a natural response of the vines is to shift growth to laterals and suckers. We performed a second suckering right after the trimming and the laterals are taken care of during our normal de-leafing and green harvest that we perform every year anyway.
Overall this new strategy for Cabernet Franc is a winner and we may try it next year in Cabernet Sauvignon and/or Merlot.
We are also conducting a small trial on west side leafing in Cabernet Sauvignon, but won't know the results of the trial until we can taste the grapes and make the wine.