The USDA Plant Hardiness Zone Map Just Changed

Heat domes, atmospheric rivers, bomb cyclones, and polar vortex—you’re not crazy, the weather is. And last week, the USDA confirmed it by releasing an updated climate zone map for 2023. And for many gardeners, that means a change in growing zones.

What are hardiness zones?

The map of the US is divided into zones, separated by ten degrees. It starts with 1a (Alaska) and goes all the way up to 13b (Puerto Rico), and the mainland U.S. tends to live between zones 5 and 10.  In between, every single part of the U.S. uses this zone classification system, which tells you roughly how long your growing season is: when it’s likely to start and finish, what kinds of conditions to expect, what your last frost date is, and more. When you shop for plants, you’ll see zones labeled on the plant tag. Knowing your zone helps you shop for seeds. To change your zone means everything you know has shifted a little bit (by ten degrees). 

Zones don’t change often—the map was last updated in 201—but when it does change, as it just did, it can upend what you know about your garden. 

How do I find my new hardiness zone?

It used to be easier to find your hardiness zone: You’d just drop your zip code into Google, and it would spit out the information. But Google hasn’t caught up with the new data yet, so for now, you'll need to visit the USDA map and input your zip code there. 

Of course, if you’ve been paying attention, you already knew the weather was changing, and your plants have been responding the way plants do: They become more resilient, or they die. So you move in new plants that are better acclimated to the current climate. 

But knowing the new hardiness zone will help you when shopping for new plants by telling you if a labeled plant will thrive in your area. It should also remind you that artificial measures to keep plants alive and thriving when they’re really not meant for one particular zone aren’t sustainable. The citrus you were trying to baby through the winters in 8b are even less likely to survive in 9a. As you shop for seeds this winter and begin growing your starts, consider seeds cultivated for your new zone.