Messy looking vineyards

While travelling around vineyards in the Niagara Peninsula and also Upstate New York, one of the things that could strike a person used to New Zealand vineyards is that the vineyards are all pretty untidy.

The contrast is that in New Zealand, virtually all the vineyards are two or four-cane vines on vertical shoot positioned (VSP) trellises. the fruit is concentrated near the bottom of the canopy on the vine, and the shoots are all supposed to be trained up. Aside from this, the sides and tops of the canopy are trimmed mechanically to give the vines a nice, neat hedge-like appearance.


Where we are now, the majority of the vineyards are VSP, but there are still lots of shoots going everywhere, up, sideways, down, over etc.

I maintain that one of the reasons that VSP is such a popular trellising system is that it can result in a very neat looking vineyard, which appeals to people's eyes. After all, most of us would take the time to make sure the plants in our gardens look tidy, trimmed and well looked after. What will people think about the state of a vineyard if it isn't in the same kind of shape? (I will have to write later about the pros and cons of a tidy-looking vineyard versus an unkept one! :-)

So what reasons can I come up with for the difference in vineyard appearance between NZ and here?

Well, one reason is the amount of rain that's fallen here this season. By all accounts, it has been a wet year, with much more rain than usual. This means the vines have access to a lot of water, which encourages vegetative growth. So at this time of season, when the grapes are starting to colour up and get into the ripening phase, we would normally expect that the grass between the rows has browned off, and the vine shoots to have stopped growing due to the lack of water.

So because the vines are growing a lot more, it means that to maintain the neat and tidy appearance of all the rows requires more work, for the same end result (this being the quality of the grapes being harvested). If there aren't enough resources (and with the economic downturn, this is a hard reality for a lot of businesses!) to go through and do all the necessary shoot positioning, lateral removal, leaf pulling and trimming, the vines start to look a bit hairy.

So this is one possible reason for the vines not looking like they do in all the coffee-table wine books laying around!

So would NZ vineyards look like this if there was above-average rainfall? Yes, they would. However, this is less likely, as most of the vineyards in New Zealand do not get enough rainfall to support vines through the year, so they have irrigation systems put in, to deliver supplemental water. So even if we have above average rainfall, it may not mean that the vines have luxury amounts of water available to them, and therefore the vegetative response is not the same as it is around here.

Wind Machines

Since I'm here in Ontario for a while, one does get to touring around vineyards (and wineries!) a bit.

In NZ, wind machines are popping up all over the viticultural landscape, as the most common type of frost occurring in the spring are radiation frosts. Something that moves the air can be very effective in avoiding freeze damage to the vines, because in such a frost cold air develops near the ground, but warmer air accumulates on top of that cold air. This is called an inversion layer, with the warm air stacked on top of the cold.

A wind machine sticks up far enough above the ground (say, 10m) to draw this warmer air down and mix it with the colder air. In most cases, there is a significant reservoir of heat in the inversion layer, meaning that the mixed air is warm enough to prevent freezing of the vine tissues for many hours.

Helicopters are also used to mix the cold and warm layers, but if a vineyard is in a location that is hit consistently with frosts, it can be worth the capital cost to buy, install, and maintain the fans.

So in NZ there are a lot of wind machines being put in to help manage spring freeze events, but here in the Niagara region, they are also putting them in. However, spring frosts are not so much of a concern here (due to the general climate and also the location of the vineyards). So why are people investing in these expensive machines?

Here the main problem is freezing temperatures during the dormant season. Grapes can be very hardy plants, surviving very low temperatures (for certain species, this can be down to less than -40 degrees C!), but vinifera vines tend to be more tender, with a critical temperature of around -18C. So if the temperature in a region tends to get lower than this on a regular basis, you had better have some methods to manage the vines to prevent damage!

One method relies on the presence of the inversion layer, which can appear in the middle of winter as well as in the early spring (or autumn). By mixing the air, freezing temperatures low enough to damage dormant vine tissues can be avoided, leading to productive vines the next season. Without some form of protection, crop losses can be 100 percent, with the added burden of having to re-train the vines (if you're lucky) or re-plant them (if you're not lucky!).

I will write on other strategies to avoid winter freeze damage in another post...

Good fruitset can equal bad news

Whilst working with some grapevines the other day I was reminded about the problems of having excessively tight clusters. Pinot noir is well known for this, but can be the case for many varieties if you have good conditions at fruit set. It can cause clusters to become so tightly packed as the berries grow and approach harvest, that berries can be popped off the cluster, causing fresh wounds where disease can get established.

As well, tight clusters are undesirable as the interior of the cluster then becomes a very good place for disease organisms to get started, as any pesticide sprays, which are a necessity to producing quality wines in some growing regions, cannot reach inside the cluster.

So while high yields are thought to be a good thing, if this is due to very good fruit set, you can run into problems, usually disease related, later on.

What are some answers to this problem?

As always, when talking about disease control, spray coverage is the most important aspect of fungicide effectiveness. Even if you have the best fungicide in the universe, it isn't any good unless it is delivered to the target. So making sure the sprayer is set up correctly, the nozzles are delivering the appropriate volume of spray and in the correct pattern, the ground speed of the tractor isn't too fast (or slow!) and the canopy is open enough to receive the spray are all important to disease control.

Aside from this, if you have good fruit set, applying a fungicide before the cluster closes up (that is, before the berries swell so much that there is no longer any airflow into and through the cluster) is your best bet to minimising disease later in the season.

If you are in an area known to have high disease pressure in the grapes themselves, choosing a variety or clone that has a more open cluster can be another effective tool.

If you must, absolutely, grow a tight clustered Pinot noir clone in this sort of area and the price you will get for the wine warrants it, then you could consider gibberellin application (if this is an approved chemical for your crop) prior to flowernig - this will cause the rachis to elongate, and thus make the cluster looser.

Another option is to do flower thinning, where flowers are removed prior to flowering. This can be done with comb-like devices, which remove some, but not all the flowers on the cluster.

In some cases, you could also trim the bottom of the flower cluster off, which allows a bit more freedom for berries to poisition themselves.

Early leaf removal has also been experimented with, where the reduced photosynthesis caused by this results in less fruit set.

These last few, though, have traditionally been done before flowering, developed for the table grape industry, where a tight cluster is one that is difficult to remove grapes from and also to pack into shipping containers.

For wine grapes, berry thinning and cluster trimming could be done after fruit set, when you have some idea of whether it was too good or not. This helps since you never really know if a season is going to provide good fruit set or not!

For ultra-premium production, where yields are often kept to very low levels, a reduction in crop is a normal occurrence, and the loss of crop through these methods can result in higher grape quality than through cluster thinning.

Minimal stock sandwich makers

While travelling with my father in law we stopped for a late lunch at a pizza place in western New York. We both ordered a sub sandwich with different meats, but lettuce, tomato etc. Shortly afterwards, one of the people in the shop went out the door and, as we later discovered, down the mall to the Tops supermarket. Minutes later, she returned with a Tops shopping bag that had lettuce, tomato and onion in it, which was then used to make our sandwiches!

Admittedly, the sandwiches were tasty and the bread was nicely toasted in the pizza oven, but we thought it odd that they had to go out once the order was placed to get some of the sandwich fixings!!