Monitoring your vineyard's mesoclimate

My last post of the year is another vineyard tip courtesy of Michael over at Amigoni Family Vineyards. He plants thermometers variously throughout his vineyard blocs to record variance in temperature of the mesoclimate. Because of slope, air flow, elevation, location of forested areas and water, etc., the temperature can vary greatly. Having a thermometer posted in each bloc, or even several for a larger bloc, can allow you to see that variance in action during a simple stroll through the vineyard.

Michael uses basic thermometers that also record the high and low temperature for a season by marking the extremes. This is especially useful here in Missouri where winter freezes can mean mortality for vinifera varietals. If you notice a temperature variance of several degrees in a winter low, say -10 degrees Fahrenheit at the top of the hill versus -13 in the middle of a slope, then you might want to plant your Chardonnay higher up and save your Cab Franc for the middle and maybe hybrids at the bottom, or avoid planting the bottom altogether. High temperatures are also an issue. Ours is a continental climate, which means we have strong extremes in the summer, too. We have hot growing conditions, and cultivars like Pinot Noir and Riesling are going to prefer the cooler mesoclimates within a vineyard as long as the winter lows won't wipe them out. You may find that the spots with the lowest lows don't necessarily have the lowest highs, and vice versa.

One note on the term mesoclimate. Most people incorrectly use the term microclimate when they mean mesoclimate. It makes sense, everyone knows what "micro" means, not so for "meso." But there are three climates that affect a vineyard. First, theres the regional climate, or macroclimate. That's the thing that we can't change. It's specific to an entire growing region, and it's what makes the Rhone the Rhone, Burgundy Burgundy, the true Sonoma Coast, Russian River Valley, etc. Then there's the mesoclimate, which is your variance in climate from bloc to bloc and row to row. We can affect that through careful planting of varietals, the direction of the row in relation to the sun and also in the winery by blending grapes from one mesoclimate within a vineyard with those from another. That's the term most connoisseurs use when they're talking about a specific vineyard's growing conditions and the style of the wine it makes. Finally, there's the microclimate, which, according to every viticulturist's good friend Dr. Richard Smart, is "the climate within and immediately surrounding a plant canopy." The temperature and humidity can be vastly different inside a dense canopy as compared to a few inches away on the outside. This is what we have the most control over through canopy management practices such as leaf removal, trellising, shoot positioning and thinning.

That's it for this year. It's been a productive year for me. We've purchased a property and vines are on order. What's more, it's a varietal with proven success in our area and one that area winemakers are excited about. See you next year.

-D

Article and blog links

_ Pinot Noir grape genome sequenced. I'm an English major and not so great with the sciencey stuff, so what does that mean in translation? Well there's talk about creating disease resistant Pinot Noir with the same flavor profile as the real stuff. If that happens I'll put a row or two in the ground as soon as I can get my hands on them.

_ Here's a nifty blog called Wine Rendezvous; it features some brief, witty videos that also have some actual information in them. The blog is a promotional vehicle for O-Chateau, a Paris wine tasting company. Cool stuff.

Review: Wine & War

Here’s a good read for when you’re iced in and your sprayer has been winterized, and before you start pruning. Despite its focus on the weighty subjects of the title, it’s easy reading, following anecdotes from winegrowers and winemakers from most of the great regions of France as they suffered under German occupation. It’s often amusing as when defiant vignerons build false walls in their cellars and re-label their plonk for shipment to Berlin. Other vignettes find winemakers facing execution for supporting the Resistance or helping to hide a Jewish family from the Gestapo. Growers also face shortages of labor for harvest or lack of copper for fungicide as the Germans commandeered all metals for their war effort. It will make you grateful that your greatest obstacle to growing good fruit is the weather, as nasty as it can sometimes be.

Jeffersonian viticulture

Wine is now being made in all 50 US states, as NPR notes in this story. The piece marks the second time I've heard discussion of Thomas Jefferson related to viticulture in the past few days. The Grape Radio guys recently posted a video from Virginia where the grower mentioned the early colonists' obsession with planting vineyards and Jefforson's own experiments with vitis vinifera in the east. "He failed miserably," notes Fletcher Henderson of The Winery at La Grange.

But the NPR story mentions that this Jeffersonian vision of a nation of backyard vineyards is finally coming to fruition more than two centuries later. It also cites that the number of wineries in this country has doubled in the past ten years. There is a renaissance happening. There are vineyards going up all over the place, a fact to which I can attest.

What's contributing to this change? Why are people planting vines on their farms or in their back yards in places like Minnesota? Is it Thomas Jefferson's prescience about the American spirit? Is it evolving conditions due to global climate change? Information sharing enabled by the "so-called Internets?" New cultivars? New techniques?

A certain amount of this can be attributed to the pioneering American spirit, Jeffersonian innovation if you will. But then China is also planting new vineyards at an incredible rate.

What seems to be happening here, though, isn't industrial viticulture. It is something done not necessarily for money, but because people are driven to do it. I'd love to make money off of our vines, but if I were to never break even I'd just be satisfied with producing good fruit. There is a sort of neo-pastoralism at work here, and I can't quite put my finger on it. I remember seeing dooryards in Beaune and Tuscany where every house featured its own vineyard, and it seems we are recapturing that sort of of pastoral Old World sensibility. Whether we do it as a natural pursuit of some rural aesthetic, or if is happening in artificially planned vineyard communities for the well-heeled, a broad cross-section of our society is getting into viticulture. Grapes are going in the ground. Wine is being made. And it's a beautiful thing.

I just called to add 50 more vines, another row, to next spring's planting of Cab Franc.

Happy holidays!

-D

Easter Freeze wrap-up

I've already written at length about what is now called the Easter Massacre that affected the vineyards in our region. I was fortunate to be able to cover a workshop held on the event for my day job. Most interesting was the use of oils to delay budbreak, which I'll try to elaborate on in a post soon.

Hilling vines

Growing vinifera in cool climates requires extra care. One additional step is hilling up of the soil around the base of the vine trunk. The goal is to cover the base of the vine up above the graft union where the rootstock is joined to the scion. If there is a hard freeze, there is a better chance of the vine surviving. The trunk will likely die, but enough wood might be insulated and preserved beneath the soil to grow a new trunk from the scion. This first photo shows two recently hilled vine rows.

There are several ways to hill up vines. Here, Michael Amigoni (aka the GoMV) at Amigoni Vineyards uses a small tractor with a side-mount grape hoe to push the mounds of soil up against the base of the vines. There are custom-designed rear-disc systems as well. The wider the mound, the greater it's insulating factor. Hilling up is essential, as a hard freeze can be devastating. In the Finger Lakes region, 25 percent of the vinifera were killed a freeze in 2004.

Planting your graft unions an inch or two off of the ground is essential for ease of hilling and to get the maximum amount of soil over the graft union, increasing the insulation factor. Here is a close-up of the hoe blade. Care must be taken to avoid damage to the vines, and one key is to ensure that the trunks are as straight as possible from proper planting and training. On a side note, multiple trunks help fend off cold damage. If one trunk is split or killed during a hard freeze, there's a chance that the second trunk might survive, ensuring that you don't lose an entire crop to that freeze event. Snow can also help insulate vines, but we don't get permanent snow cover here in central Missouri. Mounding can also be accomplished with mulch or straw, but soil has a greater insulation factor. It can be done by hand, as in this backyard vineyard.

Hilling vines is just one technique in reducing winter damage in cool climates. Trunk renewal is another technique; this involves training a new cane every few years to replace an older trunk so that you don't have all trunks of the same age. That way a freeze that kills the older trunks might spare the younger wood that has undergone fewer freezing winters and less mechanical (tractor) damage. Here's a great summary of some cold weather practices in Canada, where they're growing Chardonnay, Sauvignon Blanc, Merlot and both Cabernets where it is not uncommon for winters to dip below -18 degrees. As rare as it is to find vinifera in our region, it is also as easy to forget that these European grape varietals has been growing in colder regions for many years and with much success. It's a challenge, but few things that are easy are worth doing.

* Update - 1/12/08 Here's an article on hilling in the OSU Wine-Grape newsletter