Weather and Climate

Winter Hardiness

It’s Everywhere!

“Hardy to zone…” It’s on many seed packets and plant tags. It seems to be important.

What does it mean, though?

What is “hardiness”, and how does it affect our gardening ideas and plans?

Let’s learn about this concept, and how we can use hardiness and our own hardiness zone to plan some of our gardening endeavors!


Hardiness Zones

The United States Department of Agriculture (USDA) has sorted specific temperature ranges into a system called the “USDA Hardiness Zone”. These temperatures are based on the coldest winter temperature that a specific area reaches.


Look around outside

If you look around where you live, you will see certain plants and trees that are “hardy” to your local hardiness zone– these are the trees that continue to live and grow, and the plants that come up every spring.

Think about other parts of the country, far away from you, either north or south. If you live in the American Southwest, you will notice that grass can be difficult to keep alive and thriving. If you live in the New England states, you will not see many cacti growing around you.




USDA Hardiness Zone Map

Where do you fall on the map below?

What's Your Planting Zone? | USDA Plant Hardiness Zone Map | The Old Farmer's Almanac


A simplified, easier-to-read map from the USDA


USDA Hardiness Zone map with detailed sub-sections

USDA Zone Map - Cleveland Seed Co.

These maps from the USDA show each of the zones, and also indicate the temperature ranges for each. Notice the areas that generally do not get colder than 40 degrees Fahrenheit. And there are also areas that get as cold as 40 degrees below!

Climate Survival

The ability for plants to survive in their native environment, or a location that has a similar climate, is based on many factors.

Many plants surviving in very hot and dry climates have the ability to store moisture in their leaves; these are the succulent plants.

Plants that survive cold winter conditions may retreat into their root systems during winter months, or may store chemicals in their leaves that act as anti-freeze, so that the water inside their cells does not freeze and destroy the cells.