What does the USDA Plant Hardiness Zone Map indicate?

The USDA Plant Hardiness Zone Map is an essential tool for gardeners and farmers, as it categorizes different regions based on their climate, specifically the average annual minimum winter temperature. This information is crucial for determining which plants are likely to thrive in a given location, as these temperature extremes directly influence plant survival and growth. Each zone is assigned a number, which corresponds to a range of temperatures, allowing for an easy reference to the suitability of various plants under specific environmental conditions. By consulting this map, growers can make informed decisions about which species or varieties to plant, ensuring better performance and resilience in their local climatic conditions.

The other choices do not accurately describe the purpose of the USDA Plant Hardiness Zone Map. Soil nutrient levels, water availability, and plant disease resistance are important factors in agriculture, but they are not represented by this map. Rather, the focus of the USDA Plant Hardiness Zone Map is strictly on temperature extremes, making it a valuable resource for understanding winter hardiness and plant compatibility with regional climates.