Why Grapes Grow Here
The wine grower, out standing in his field, is asked by the curious wine drinker, “Why do grapes grow here,” pointing to the grapevines surrounding them, “and not there?”, pointing to a nearby field without vines.
“A very good question,” the wine grower replies. “Refresh your flute with a bit more of this sparkling wine – it’s Talisman, which comes from this vineyard, by the way – and I’ll try to answer.
“Here, where these vines are, is, as you can see, on the slope of this hill. The vines are planted from the top of the hill, that ridge line over there, and extend down the south and south west facing slopes. But they don’t go all the way to the bottom of the slope. That field you pointed out, there in the valley, lies below any vines. Lower elevation. The vines are planted on the slopes, not in the valley.
“In the late spring, when we have a cold, frosty morning, the cold air, being heavier than warm air, flows down the slopes into the valley. On those mornings, the slopes are warmer than the valley, and the tender grape buds are spared the cold. If the vines were planted in the valley, the buds would freeze, and the crop would be lost.
“In the fall, too, the same thing happens. Then, the leaves are spared, and they can continue to work to ripen the grapes.
“Here, on the hill, the number of days between the last frost in the spring and the first frost in the fall, is greater by two weeks or more. This longer growing season allows the grape vines to grow longer, and ripen their grapes better, and the wine that comes from those grapes is much better.
“That’s one reason we grow grapes here, on this slope, and not there, in the valley.”
“I see,” said the wine drinker, sipping from his glass of sparkling wine. “One reason, you say. There are other reasons?”
“Yes,” the wine grower replied. “Though that’s the most important reason. It’s also true that these slopes facing south, or south east or south west, are angled to receive the sunlight better than land that is flat or north-facing. That’s important here, as we have a short growing season, and need to take advantage of everything we can to increase the ability of the vine to capture sunlight for heat and photosynthesis . Grape leaves don’t do much photosynthesis at temperatures below 55 degrees Fahrenheit, and are most efficient between 60 and 80 degrees. So it’s important to grow vines on slopes that warm up early in the day, and stay warm later in the evening. Here, we have many early morning hours in late spring or fall that are sunny and cool. Those slopes facing south warm quicker, getting above 55 degrees and allowing the grape leaves to begin their work of growing shoots and ripening fruit.
“Of course, in some parts of the world where the climate is much warmer, grape growers must plant with the opposite in mind. They may try to keep the vines from getting too warm in the day, so they may plant on north facing slopes, or do other things to keep the vines cool during the heat of the day.”
The wine drinker smiled, “Well, that all makes sense, but I see that the grass growing here between the vine rows is sparse, yet that growing here in the open space in the valley is lush. Doesn’t that indicate that the soil here is not so good as that in the valley, and wouldn’t the vines grow better in the better soil?”
“Yes!’ exclaimed the wine grower, “Exactly right! Another good reason not to grow grapes in the valley.”
“What? Don’t grow them where they’d grow well? Why not?”
“Well, if we want to grow grapes to make the very best wine, we don’t want grapevines that are too lush, too luxuriantly growing. We want vines that are balanced, that grow leaves and shoots and grape clusters in proper proportion to each other. There in the valley, the topsoil is richer than here on this slope, and the extra nutrients in that soil would tend to make for grapevines that are larger, with more leaves, more prone to grow a lot during the summer. And because of the shorter growing season there, remember, the vines would not have as long to ripen their grapes. They would, more often than not, yield a large crop of not so ripe grapes, and from that we could only make indifferent wine. We want to make different wine.” The wine grower said, smiling.
“So you grow grapes here because the soil is worse, the cold air falls down off the slope, and the slope heats up earlier in the day. Is that it?” asked the wine drinker, sipping from his glass.
“Yes, basically that’s why we grow grapes here and not there,” the wine grower replied, pointing first to the vines and then to the valley.
“OK,” said the wine drinker. “But I live near Ann Arbor, and we have hills there, too, slopes like this. Yet I see vineyards only here, around Traverse City, and in the southwest part of the state, Paw Paw, Fennville, that area. Why don’t people grow grapes near Ann Arbor, or Cadillac, or Calumet? There are hills there, too.”
“Lake Michigan,” replied the wine grower, seriously. “Look at the photograph on the cover of this issue of the Wine Country. What do you see? Land and water, water and land, mingling, adjacent.”
The wine drinker, startled, looked at the cover of the latest issue of Wine Country, which had appeared in his hand, somehow. Indeed, there was Leelanau County and Lake Michigan and Grand Traverse Bay. [He couldn’t see himself and the wine grower, but knew they were there on one of the hills between Suttons Bay and Traverse City, too small in the picture to be seen. Odd.]
“Ann Arbor and Cadillac don’t have the proximity to Lake Michigan required for making a success of wine grape growing,” the wine grower continued. “A narrow band along the east shore of Lake Michigan, wider in southwest Michigan, narrowing to ten miles or less as far north as Traverse City, is influenced by the lake, making the climate in that narrow zone favorable for growing tender fruit plants like wine grapes. We call it the lake effect, and without it, there would be no grape growing here.”
“How does it work?” asked the wine drinker, “this lake effect, what is it?”
“Well,” said the wine grower, “the answer to that question will have to wait until the next issue. I see that you’ve run out of wine, and my space here is full. Let’s go back to the cellar, get another bottle of sparkling wine, and continue this discussion in the fall.”
-Copyright © 1999 L. Mawby