hardighetssoner

Hardighetssoner, also known as hardiness zones or plant hardiness zones, are geographical areas defined by a specific range of average annual minimum temperatures. These zones are primarily used in horticulture and gardening to determine which plants are most likely to survive the winter in a particular location. The most widely recognized system is the USDA Plant Hardiness Zone Map, developed by the United States Department of Agriculture.

The zones are numbered, with lower numbers indicating colder winter temperatures and higher numbers indicating warmer winter temperatures. For example, Zone 1 represents the coldest regions with average annual minimum temperatures below -45.6 °C (-50 °F), while Zone 13 represents the warmest with average annual minimum temperatures above 10 °C (50 °F). Each zone is further divided into sub-zones, denoted by 'a' and 'b', representing a 5 °F (2.8 °C) difference within the zone.

When selecting plants, gardeners refer to the hardiness zone rating provided by the plant's tag or description. A plant rated for Zone 5, for instance, is expected to survive winters in Zone 5 and any zones with higher numbers (warmer climates). However, it may not survive in zones with lower numbers (colder climates). It is important to note that hardiness zones are a general guideline and other factors like soil type, moisture, sunlight, and microclimates can influence plant survival. Other countries and regions have developed their own hardiness zone systems based on local climate data.