Chill Hours for Grapevines and Fruit Trees Explained Cold hours, also known as chill hours, are crucial for the health and productivity of many types of grapevines and fruit trees. These hours refer to the amount of time a plant is exposed to temperatures between 0°C and 7°C (32°F to 45°F) during dormancy, typically in winter. Understanding the role of cold hours, the challenges that arise when they are insufficient, and the ways to mitigate these issues can ensure the vitality and productivity of your plants. What Are Chill Hours and Why Are They Important? Many grapevines and fruit trees, including apples, cherries, peaches, and certain grape varieties, require a period