Faith-Based Viticulture | March 2007
In this stage of my winegrowing career, I have come to focus on certain viticultural ideas and practices that I am comfortable with. I have never had an original idea when it comes to viticulture. After a 2,000 + year collective effort of winegrowing, that would be quite a feat. I had intended to title this article “Vine management and wine quality” but “Faith-Based Viticulture” is being more honest.
I admit that I am a man of scant science background. I avoided the sciences during my academic career. According to my colleagues, a degree in Political Science does not qualify as the right kind of science. This, I suppose, has made me a bit of a skeptic.
I am, however, a trade journal junkie. I subscribe to dozens of regional, national and international winegrowing publications. Friends also graciously forward me an amazing amount of information from the web. Wine grapes are the most scrutinized (legal) crop in the world. I read research results, scientific papers, and anecdotal stories.
I have a library of books on tasting, evaluating, and even scoring wines. I have also tasted with hundreds, if not thousands, of wine professionals and enthusiasts. I have judged in a number of wine competitions. I always find the frequent opposing opinions on a particular wine both comforting and alarming.
While all this is extremely interesting and often very useful, I have also come to the conclusion that it is impossible to definitively correlate any single viticultural technique to improved wine quality. Wine quality is subjective. Science is objective. Seasonal weather variations are dynamic.
Experiential intuition is ultimately what drives my decision-making. Faith is what keeps me focused. On my site, appropriately called “Hardscrabble,” this is what I currently believe makes viticultural sense in my quest to achieve a great wine:
Balancing the vine
Recently I queried two colleagues, one with experience in Bordeaux and another with experience in Burgundy. I asked if they could see a difference in the vines coming from the Grand Cru vineyards versus the simple village vineyards. Both answered the same. The highest regarded vineyards had the smallest vines.
I define a balanced vine as:
- requiring only one light hedging per year
- shoot tips cease growing at veraison
- small, inconsequential lateral shoots
- little or no secondary crop
- hardening off of canes beginning at veraison
In order to achieve this level of balanced vine in my vineyard, I have had to be very manipulative and interventionist. I am now comfortable with this kind of ‘extreme viticulture’, as I have found that in doing so, I can be very laissez-faire with the resulting wines in the cellar.
After 20 years of trying to adapt my training and trellising (Lyre and Geneva Double Curtain) to accommodate my most vigorous sites, I have now adopted another strategy of manipulating the vine roots to conform to a tighter spacing on VSP. In both situations the goal is the same: achieving a balanced vine.
Instead of “beating back” overly vigorous vines using canopy management techniques such as canopy division, hedging, aggressive leaf pulling and lateral removal, I am addressing the imbalance underground, primarily using a combination of competitive cover crops and intentional nutritional deficiencies.
For three years now I have witnessed the good the bad and the ugly of using cover crops to compete with vines in order to achieve balance in densely planted vineyards. Often the cover crops have worked too well resulting in stunted vines with severe nutritional deficiencies. I am learning to manage the cover crops by mowing and herbiciding in order to reduce or increase its competitiveness according to the soil/vine/water/vigor relationship as the season unfolds. This can be a daunting task, but the results have been extremely encouraging.
I have found that a moderate amount of competition before bloom seems to help with fruit set and keep shoot internode length short. However, the post bloom/berry development period is when my vineyard has experienced significant nutritional deficiency symptoms, as was confirmed by petiole analysis. Nitrogen and phosphorous levels were dangerously low. I began to feed my vines small, maintenance doses of diammonium phosphate (DAP) during this period: enough to keep the leaves productive, but not too much so as to over stimulate vigor.
There are three areas of canopy management where I have been changing my approach: pruning, shoot thinning, and leaf pulling.
1. Pruning. I am in the process of converting most of my vineyard from cordon pruned to cane pruned. This is a very involved procedure. I cringe every time I pull out my saw to make another big cut. The reasons for my conversion are:
a. Disease prevention. I am losing cordons to wood rot organisms (I think from the many large pruning wounds around the spurs) and the rot is spreading down into the trunks. I also have a big problem with phomopsis that over-winters in old wood (spurs).
b. Mites. I have also found cane pruning can decrease early (just post bud break) mite pressure. It seems that the mite eggs over winter around old spurs. Dormant oil sprays have not been effective as many of the eggs are protected under bark. I noticed several years ago that when renewing old cordons with new canes, I could have heavy mite infestations on newly emerging shoots coming from cordons, but the shoots coming from canes were mite free.
c. More open canopy in the fruiting zone. Once cordons get large they can start to take up a lot of space in the cluster zone. In some cases I felt that they were interfering with air flow and perhaps providing greater innocculum for some bunch diseases (again, phomopsis).
d. Less labor shoot thinning. With some varieties (Petit Verdot, Cabernet Franc, Sauvignon Blanc and Seyval), we often had to make 3 suckering/shoot thinning passes as the continually send out new water sprouts from -blind buds” in the spur and cordon areas. Cane pruning avoids this problem and shoot thinning only requires one quick pass.
2. Reducing the number of shoots per foot of canopy. Once I was able to get more of a handle on my vigor problem I was able to reduce the average shoot density in my canopy. I average from 2 to 3 shoots per foot. This opens up the canopy to light. It also reduces the amount labor required to shoot position, tie and cluster thin.
3. Leaf pulling. In our relatively hot climate, I am trying to preserve acidity in white grapes by retaining leaves on the south and west sides of the fruit zone. We do pull leaves on the east and north sides a few weeks after flowering for disease prevention. With the reds, we do a light pulling on both sides of the canopy early in the season to get dappled sunlight on the clusters. We then go back once the sun gets lower in the sky (September) and pull very heavily to try to get more ‘cool’ sun on the clusters. I feel that this helps reduce vegetal flavors, improves tannins and color and helps the ripening process (our reds push the envelope on ripening as we harvest them in October and occasionally November).
What kind of wine do I want to make? I have found that yields have a huge impact on wine style. Within my 20-acre vineyard I have a wide variety of soils. I am convinced that certain soils (heavier, deeper and more water retentive) will never produce great wines. The wines coming from these soils are always designated into what I call “starter” wines: simple, straightforward and relatively inexpensive. I now crop these vineyards at a higher level than my better sites. I have found that a lower yield on the high vigor sites will not give me significantly better wine, but the opposite is true on my root restrictive, well-drained soils.
These “Grand Cru” sites only show their stuff at yields below 3.5 tons per acre. In most cases this requires cluster thinning. I now have good historical data on average cluster weights for all my blocks. I do admit to doing “eye ball” estimation in mid-summer when I comes to determining whether that season’s cluster size is typical.
There are some years when it becomes evident right after fruit set that we will be dealing with an excessive crop. If this is the case we will drop clusters when we are leaf pulling. More typically we get to cluster thinning for the white-fruited varieties at pre-veraison. I do feel that a large crop between flowering and veraison will slow vine vigor. I use this as a tool to help control vine balance, thinning early on lower vigor vines and later on my more vigorous sites.
With the reds we always do a green harvest thinning at about 70% veraison. It is our final crop adjustment and the only time we can visually determine uniformity of ripeness. One down side of cane pruning is that cluster size has increased. In many cases we will retain the smallest cluster and even remove part of that cluster, usually the shoulder.
I am always asking myself what else could be done in the vineyard to improve wine quality. A friend has been pushing the idea of tarping the vineyard after veraison in order to shed late season rainwater. It sounds extreme and expensive, but it is done with crops less valuable than wine grapes. A few mavericks (garagists) have been experimenting with it in Bordeaux. I am a traditionalist and purist in the cellar and eschew techniques such as reverse osmosis and additives, yet I don’t have the same attitude in the vineyard. Is this hypocrisy or is this simply having faith in which path will make the best wine?
Wine East, March 2007