Because the state is so large, it is actually further broken down into Northern and Southern planting zones. A northern half of a California planting zone can be anywhere from 5a to 10b. The southern region has zones 5a to 11a. Planting zones help determine when and what to plant throughout the year.
How to understand USDA hardiness zones?
About hardiness zones. The USDA’s Agricultural Research Service and Oregon State University’s PRISM Climate Group developed the current map,introduced in 2012.
What determines plant hardiness zones?
The USDA determines hardiness zones by addressing the average annual extreme minimum temperature of an area over a period of 30 years. Zones should be interpreted as guides, rather than absolutes; be sure to always consider light, soil moisture, temperature, humidity, and duration of cold-weather when selecting plants.
What exactly is a plant hardiness zone or frost zone?
A hardiness zone is a geographic area defined to encompass a certain range of climatic conditions relevant to plant growth and survival . The original and most widely used system, developed by the United States Department of Agriculture (USDA) as a rough guide for landscaping and gardening, defines 13 zones by annual extreme minimum temperature.
What do plant hardiness zone numbers mean?
Most hardy plants have a zone rating to indicate where they will survive the winters from year to year. Maybe the plant you have your eye on is hardy in Zones 5-9, and you live in Zone 4. That could be iffy, but you could try it if you don’t mind a little risk for the thrill of growing something that normally wouldn’t survive in your region.
