You might recall recent letters detailing a romp in the mustard fields with granddaughters,
pre-Womer Memphis trip tidbits, and post-Womer Memphis trip sentiments.
You might be tempted to ponder, “don’t those folks at Gundlach Bundschu ever think about winemaking?” We are in fact well into the 2007 vintage growing season, and as an estate winery, we are extremely busy in the vineyard. The beginning of harvest is approximately 55 days away.
It is the end of June and the grape vine flowering is completed. Up to this point, a great deal of work has been done to manage the growth of the vine’s shoots and leaves. In all 60 blocks we have moved the trellis wires as many as three times in order help the growing shoots maintain their vertical position; we have head and trunk suckered each vine (ie removed extra shoots that could throw the vine off balance); and we are in the process of pulling excess leaves from each shoot in order to expose each young grape cluster to just the right amount of air and sunlight while avoiding sunburn.
We trapped 143 gophers out of the three year old block of Gewürztraminer along the lane, much to the relief of the delicate juvenile vines, and we are preparing three additional blocks to be replanted next spring with new Gewürztraminer and Cabernet Sauvignon.
Each of these (and many more) vineyard practices have been repeated vintage after vintage here on Rhinefarm, but every year they need to be tweaked to accommodate various growing conditions and new grape growing technology. Winemaker Linda Trotta and her vineyard management crew meet weekly to discuss each practice in great detail.
Here is an example of one week’s agenda from a meeting just last week. Even if many of the terms are new to you, the detail will give you a sense of the intense process required to stay on the cutting edge of producing world-class estate wines.
A. Petiole analysis (leaf stems are tested for vine nutrition status)
1. It is normal to see low irons in spring, even a dry one like this year; iron will reverse through season; no action needed.
2. High Zinc in various blocks -- should continue to be observed, likely normal.
3. A1 and A2 (Pinot Noir blocks) could use a boost of Phosphorous and Potassium, but Nitrogen levels are good.
B. Mildew Control: Our mildew control efforts have been successful so far this season. We’ve been applying sulfur dust or stylet oil (both registered organic compounds) to individual blocks, depending upon the unique need of the block. The next round for “oil blocks” starts June 22nd and 25th. The next round of “sulfur dust blocks” starts June 20th.
C. Irrigation: Because of a dry spring, be certain our controlled deficit program is very accurate. There is not the usual reservoir of soil moisture available this vintage. Heather and Nicole continue to take weekly leaf water potential readings of each block. (Leaf water potentials are measured using an instrument called a Pressure Baume, which is an instrument that measures water content in the leaves. This is one of the tools we use in strategizing our water applications).
D. How does the data on shoot elongation compare to vine water status? (ie are the vines slowing their vegetative growth at a time that supports optimal fruit ripening). This data is helpful in determining irrigation needs. Be certain it is plotted accurately.
F. All to review the website for Dr. Mark Mathew’s UCD lab where he has posted research on the differences between bunch stem necrosis (BSN) and berry shrivel (BS), to aid in identifying and dealing with these potential late season issues.
Through these frequent meetings at each stage of the growing season, where we strategically and meticulously address each wine growing practice, we are able to stay on the cutting edge of producing balanced, evenly ripened grapes, which is essential to producing great wines.
Salud Amigos
Jim
