Here’s everything you need to know about plant hardiness zones and how to determine which one you’re in.

The Plant Hardiness Zone Map is based on the average annual extreme minimum winter temperature, displayed as 10-degree F zones ranging from zone 1 (coldest) to zone 13 (warmest), the USDA notes.

This map also allows you to plug in your zip code to find out your exact planting Zone. My zip code in Linn County places me in Zone 5a, but I have lost Zone 5 hardy plants in my garden.

Starting a successful garden begins with knowing your planting zone. These maps can help.

The map and its zone system are designed to help gardeners and farmers understand a plant’s ability to survive the winter and thrive where they live.

The 26 zones are based on 5-degree increments, but gardeners can get more precise data by plugging a ZIP code into the map (www.planthardiness.ars.usda. gov).

Compared to the 1990 version, zone boundaries in this edition of the map have shifted in many areas. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map ...