I feel I've been focusing pretty heavily on winemaking, and not so much on the viticulture, or grape growing portion of my knowledge lately. So, lest I forget those grapes... here's a post on how humans manipulate the vines to give us what we want from their fruit!
Grapevines are pretty fascinating little plants. If you've ever been to a vineyard, you've noticed, I'm sure that they grow in neat rows, and most often the vines have been trained to grow up along trellis wires (there are lots of different ways to train vines. Sometimes they're allowed to sprawl down on the ground, sometimes they are trained up onto an overhead trellis and they then hang from above... lots of ways. Lots of reasons for doing it each way...) Have you ever wondered why we grow them this way? What else goes into getting them to grow the way we want them to?
Well, in nature, grapes can grow like weeds. They'll find a tall tree, climb it, and just go to town. This isn't great for people- we aren't really made for climbing tall trees. So, to make things easier for ourselves, we have trained them to grow on wires, trained at just the right height for picking!
However, a lot more than just ease of harvest goes into our care of grapevines. We discovered that if we whack and feed and coddle the vines, we can get them to give us better, more flavorful fruit! Ideally, vines have a perfect balance between their foliage (called canopy) and fruit to make sure the fruit is flavorful and sugar rich. If the vines spend too many nutrients growing new shoots, the fruit will suffer. Contrastingly, if the vine grows way too much fruit, each berry will have less sugar and flavor compounds.
Only so much the vine can do- so we've taken it upon ourselves to manipulate it to give us the best crop possible.
How do we do this?
A) Nutrients. Depending on the soil, the grapes may not have enough of what they need to grow and produce good fruit. Nitrogen, in particular, is vital for wine grapes because the yeast needs it for fermentation. So, we test the soil, we test the vine's tissues, and we see what it needs more or less of. Some nutrients are applied topically, and some to the soil/water.
B) Watering. Ideally, you water the vines early in the season, get them to grow, and start fruit, and then late in the season, once the grapes have changed color, you shut them off. This forces the grapes to taper off growth and use their energy and life processes to concentrate all their sugars. (The bigger the berry, the more water, the more diluted the sugars and flavors.)
C) Pruning. People have different preferences and styles for pruning, just like they do training systems. But the basic idea is the same. Keep just the right amount of canopy to keep the fruit from getting sunburned, keep enough airflow that molds and other diseases don't take root (depending on where you are located) but don't let it go so crazy that the vine sends nutrients to canopy growth instead of to the berries.
You have to prune at the right time in the season too. If you do it at the wrong point, you can actually stimulate more growth, channeling those sugars to the wrong place again... Or contrastingly, you can chop off developing fruit and really get yourself into trouble.
Most small scale producers would rather have a little bit less tonnage harvested in favor of really high quality fruit. Smaller is often better. However, a lot of large wineries that produce wines in tanks the size of a building (no joke) would rather maximize the amount of fruit harvested and are willing to sacrifice a little bit of quality (one of the reasons your grocery store wines are cheaper than the small-scale boutique wines you buy in tasting rooms. )
Some growers, however, believe that we meddle too much with the vines' fruit/canopy balance. They argue that in nature, the vines actually manage to balance themselves just fine and we should back off.
It is becoming popular in many circles to train the vines onto wires early in their lives, to perform necessary winter pruning, but to otherwise pretty much leave them alone during the growing season. Don't mess with pruning or chopping. They still pay attention to watering and nutrients (and in many climates have to still worry about pests and diseases) but will try to be as hands-off as possible.
There are conflicting studies, but some show that the fruit quality is just as high and yield is just as ideal in these vineyards as in those that do more canopy management...
I have mixed feelings and can see the pros and cons in each situation. However, I think I'm inclined to mess with the canopy. I'm too much of a control freak, and there's too much risk involved with having a crummy crop to step back that much. I'm all for meddling and getting them to give us what we want. We know how, so why not?
This is a very, very bare-bones explanation as to what goes into growing a healthy vine. But there you go. Any questions? Was this confusing? Those who know more than me- did I omit any major points? Talk amongst yourselves in the comments.
Did you know?
In some regions of Portugal, until pretty recently, farmers would grow grapes for winemaking on giant poles and under them, they'd plant their gardens and food crops for their families. Talk about maximizing your horizonal space!