🌿 Frost

Frost means cold nights with temperatures below zero. In spring it kills young buds and shoots of the vine. For vineyards it is one of the main threats.

When the vine wakes and starts to grow, buds swell and open. At that time they are very tender. Frost of just a few degrees below zero can damage them, and then the harvest is smaller or lost entirely. The most dangerous frosts come after budburst. They occur in areas with a continental climate, where spring can be cold and unpredictable, and in low-lying places where cold air collects.

Growers have ways to protect vines. They can light frost candles, which warm the air a little. They can use wind machines that mix cold and warm air, or sprinkle the vines with water so that a protective layer of ice forms around the buds. Sites are chosen too: on slopes cold air drains downhill, so the top of a slope is safer. Frost is part of a vineyard's climate, and the risk of it influences where and which grapes are planted.