kylmäkestoisuusvyöhykkeitä

Kylmäkestoisuusvyöhykkeitä, commonly known as plant hardiness zones, are geographic areas that have specific minimum winter temperatures. These zones are used to determine which plants are most likely to survive the winter in a particular location. The system was originally developed by the United States Department of Agriculture (USDA) and has been adapted by other countries and organizations.

The zones are based on the average annual extreme minimum temperature during a winter. The lower the zone number, the colder the average minimum temperature. For example, Zone 1 has the coldest minimum temperatures, while higher numbered zones have milder winters. Each zone is typically a 10-degree Fahrenheit (about 5.6-degree Celsius) difference from the next.

When selecting plants, it is important to consider their hardiness zone rating. A plant rated for a warmer zone than where it is being planted is unlikely to survive the winter. Conversely, a plant rated for a colder zone than its planting location will likely thrive. Many plant tags and seed packets include a hardiness zone recommendation to help gardeners make informed choices. Understanding these zones is a fundamental aspect of successful gardening and horticulture in regions with cold winters.