säilytysvyöhykkeet

Säilytysvyöhykkeet, often translated as "storage zones" or "hardiness zones" in English, are a system used to categorize geographical areas based on their minimum winter temperatures. This classification helps gardeners and farmers understand which perennial plants are likely to survive the winter in a particular location. The most widely used system in Europe is based on the USDA Plant Hardiness Zone Map, although some countries have developed their own adaptations.

The zones are typically numbered from 1 to 13, with zone 1 representing the coldest areas and zone 13 the warmest. Each zone is further divided into 'a' and 'b' sub-zones, indicating a 5-degree Fahrenheit (approximately 2.8-degree Celsius) difference within the zone. For example, zone 6a is colder than zone 6b. When a plant's hardiness is listed, it indicates the coldest zone in which the plant is expected to thrive.

When choosing plants, it is crucial to consider the zone rating. A plant rated for zone 7 will likely not survive a winter in zone 5. Conversely, a plant rated for zone 4 might be able to grow in zone 7, but it may not flower or fruit as prolifically due to warmer temperatures. Local microclimates, such as proximity to water bodies or urban heat islands, can also influence plant survival, meaning actual success might vary slightly even within the same zone. Understanding these zones is a fundamental aspect of successful perennial gardening and agriculture.