For winemakers, spring marks the shift from winter dormancy to reawakening. In the vineyard, the groundwork for harvest is laid and important transitions occur, from de-acclimation, bud break and flowering, to cover crop, vine replanting and more.
Spring isn’t without its hazards, nor immune to the changing climate. Nevertheless, “spring is made of solid, 14-karat gratitude, the reward for the long wait,” as author Barbara Kingsolver wrote in Animal, Vegetable, Miracle: A Year of Food Life.
Life of the Vine
As soil temperatures warm, sap begins coursing through vines. This triggers a sequence of events that eventually results in the appearance of fruit on the vines.
Bud break is the first stage of the vine’s annual cycle. New green growths appear, fed by water and stored nutrients. Small, fuzzy (or, as the pros say, woolly) nubs sprout. As temperatures increase, tiny leaves, tendrils and miniature flower clusters burst through the bud.
“Every day is a step towards the next vintage,” says Lawrence Cronin, winemaker for Tenuta di Arceno in Tuscany.
Grape flowers arrive typically in late spring, roughly from 40 to 80 days after bud break. Vines are self-fruitful, which means that they self-pollinate without bees or wind. Each flower bears a single grape that protects the plant’s evolutionary insurance policy, its seeds.
“This is a very delicate time that is easily impacted by the weather,” says Cronin. In Castelnuovo Berardenga in Chianti Classico, the ideal conditions are from 59°F to 68°F, he says, without rain and little or no breeze.
“For the weather to stay like this consistently for two weeks would be a dream,” he says. “Any rain or wind during this time can hamper flowering, disrupt pollination and lower the potential yield.”
“Every day is a step towards the next vintage.” —Lawrence Cronin, Tenuta di Arceno
Shatter, or coulure, occurs when the grape cluster doesn’t fully develop. Reasons include strong winds knocking flowers off or disrupting pollination, or the small berries falling off before developing.
Shatter isn’t always bad. A “sparse cluster” can help a grape like Sangiovese, Cronin says, because it has tight bunches that can impede airflow and lead to botrytis. Still, “everything in moderation,” he says.
Viticulturalists and winemakers rejoice when the weather turns warm.
“Spring is my favorite time of year,” says Emily Faulconer, agricultural engineer and chief winemaker for Viña Carmen in Chile. “Sunny days, the Andes covered in snow, the start of new life. Pleasant weather, the cover crops growing, butterflies. I simply love it.”
Come spring, Faulconer and her team tackle planning and maintenance projects in the vineyard like planting cover crops, removing extraneous shoots and lifting new vine growth.
“At our Alto Jahuel estate, we plant cover crops between rows and apply hummus and mulch directly on the vines,” she says. She plants native flora as cover crops because it’s familiar to the local fauna. They have evolved into a symbiotic, living ecosystem. “It is impossible to achieve the expression of the terroir if there is no life in the vineyard,” she says.
Ntsiki Biyela, the owner/winemaker of Aslina Wines in South Africa, also ramps up vineyard management the spring. Since Ntsiki’s vineyards are certified by the Integrated Production of Wine (IPW), a voluntary environmental sustainability scheme, she takes extra care to set up corridors of local fynbos and succulents between vineyards. This creates natural habitats that attract beneficial insects.
The laborious task of desuckering also begins in earnest. To remove unwanted shoots that pull water, energy and nutrients from developing fruit may sound familiar to tomato gardeners who pluck small suckers between plant stems and branches.
“Spring is my favorite time of year. Sunny days, the Andes covered in snow, the start of new life… I simply love it.” —Emily Faulconer, Viña Carmen
Toward the end of spring, shoot growth becomes unwieldy. Vines meant for trellises are lifted off the ground with moveable wire and set into an upright position. Trellis systems have multiple benefits. They lift heavy fruit off the ground, maximize sun exposure and airflow, and make maintenance passes and harvesting easier.
If vines need to be replanted, whether from disease, old age or changing varieties, growers do so in the spring.
Spring may be a season of regrowth, but it also presents hazards for tender plants. Late-season frosts are particularly threatening.
Over the last decade, Burgundy drinkers, especially devotees of Chablis, have witnessed frost’s devastation. Vines are sensitive to injury, or even death, from freezing temperatures once growth restarts. Lethal temperatures range from 26°F for swollen buds to 30°F during the leaf stage.
Aside from site selection and delayed winter pruning, active spring measures to fight frost come down to modifying temperatures in the vineyard. Wind machines and fans can stop colder air from settling around vine trunks.
Another tool is smudge pots, which are oil-burning heaters with chimneys once common in Europe. Smudge pots generate air currents that disrupt cold air from settling around vines. Modern versions include candles that burn biofuels.
Aspersion, or sprinkling water on vines before a temperature dip, protects the plant. Though it seems counterintuitive, this layer of ice shields it from colder temperatures.
Frost events have gotten more intense and erratic, which some experts attribute to climate change. Places that seldom or never saw late spring or fall frosts, like Lebanon, have suffered unexpected and damaging events.
Faulconer says climate scientists predict an increase in snow and frost events in the Andes Mountains near the Maipo Valley.
“While it is positive to have more snow, as it secures our water supply, the frosts are a negative,” she says. “We are improving our frost alert system to be able to react faster. We have also planted with taller trellis systems.”
For every three or so feet that buds are lifted off the ground, the temperature increases almost 1°F. The benefit “is quite considerable,” says Faulconer, given the small temperature margins in which frost can injure vines.
Nevertheless, for all winemakers, spring remains a season of hope.
“Spring is a beautiful time of growth for the vines, and for humanity and life, too,” says Biyela.