USDA Planting Zones Explained: Find Your Growing Zone
Learn how to find your USDA planting zone on the hardiness map and use it to choose the right plants and plan your garden with confidence.
Knowing your planting zone is crucial to choosing plants that are well suited to your garden. In the US, this is known as your USDA hardiness zone: a numbered area based on the coldest winter temperatures where you live. It helps you work out which perennial plants are likely to survive winter and return year after year, and which tender plants may need to be treated as annuals or protected from the cold.
The advice in this article is primarily aimed at gardeners in the US. However, if you garden in Canada, the UK, Australia, or elsewhere in the world, it is worth finding the closest equivalent of your USDA zone. This will help you apply the growing advice on this site more accurately to your own garden.
Below, we explain how to find your USDA zone by state and read the map, so you’ll be better able to select plants for your garden.
What Are USDA Hardiness Zones?
The US Department of Agriculture (USDA) created the plant hardiness zone system to help gardeners identify which plants are likely to survive winter in their area. The first USDA hardiness zone map was published in 1960 and was subsequently updated in 1965, 1990, 2012, and most recently in 2023.
Each USDA hardiness zone represents a 10°F range based on an area’s average annual extreme minimum winter temperature. For the 2023 map, this was calculated using weather data collected between 1991 and 2020.
Zone 1 is the coldest, with average annual minimum temperatures of -60 to -50°F (-51.1 to -45.6°C), while zone 13 is the warmest, at 60 to 70°F (15.6 to 21.1°C). Each zone is further divided into two 5°F subzones, labelled “a” and “b.”
The map should be used as a general guide rather than a guarantee. It reflects average conditions, so an unusually severe cold snap can still damage a plant that is normally hardy in your zone.
Hardiness zones are only one way of describing a region’s growing conditions. Temperature, rainfall, humidity and seasonal weather patterns also help determine its broader climate zone, which can provide additional guidance when choosing and caring for plants.
What Planting Zone Am I In?
You can use this high-resolution USDA map to pinpoint your gardening zone. If several zones appear close to your location, find your state map for a more accurate picture.
In most areas, the correct zone is easy to identify. However, local and regional variations can mean that two or more zones occur close together. The USDA’s ZIP code tool is handy for these areas.
If your garden lies close to a zone boundary, an outdoor minimum-maximum thermometer can help you understand its particular microclimate and track how cold it becomes over successive winters. This Brannan digital thermometer from Amazon does the job. Position it near the planting area rather than against the house, where readings may be warmer.
Planting Zones by State
To find your zone, select your state or region in the list below to view a detailed hardiness zone map of your location.
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Why Has My USDA Zone Changed?
If your USDA hardiness zone has changed since you last checked it, this does not necessarily mean that your local climate has suddenly become dramatically warmer or colder. The 2023 map uses more recent temperature data, collected from 1991 to 2020, while the previous map was based on data from 1976 to 2005.
Around half of the US moved into the next warmer 5°F half-zone on the 2023 map, while the other half remained in the same half-zone. Some boundaries also changed because the new map draws on more weather stations and improved mapping methods that account more accurately for factors such as elevation, terrain and proximity to large bodies of water. In some places, these improvements resulted in a cooler rather than warmer zone.
Remember that the map remains a general guide rather than a guarantee of plant survival. A change of half a zone does not necessarily mean you need to replace established plants or immediately start growing less hardy varieties.
Gardening for Your USDA Zone
Identifying your USDA zone is just the first step. To use the guidance successfully, you need to understand plant labels, only choosing varieties suited to your climate – as well as other factors like soil type, sunlight, and maintenance required.
Choose Plants That Match Your Zone
When selecting a perennial, check its recommended hardiness range. Hardiness refers to a plant’s ability to survive winter temperatures, so a perennial rated for your zone should usually survive in the ground and return the following year. A plant labelled for zones 5–9, for example, should be capable of surviving winter anywhere within that range.
If your zone is colder than the lowest number listed, the plant is unlikely to survive winter outdoors, although it may sometimes be grown as an annual or overwintered indoors. A plant can also struggle when conditions are warmer than its recommended range.
USDA hardiness zones measure only winter cold, so they do not reveal how much summer heat a plant can tolerate. A plant suited to zones 3–4, for example, may struggle in zone 8 because conditions are too warm. For a fuller picture, check the American Horticultural Society’s heat zone map, which groups areas according to the number of very hot days they experience each year.
Many online nurseries allow you to filter plants by USDA zone, making it easier to avoid costly mistakes. For example:
- Perennials filtered by growing zone at Plant Addicts
- Evergreen trees suitable for your zone at Fast Growing Trees
- Compatible shrubs and hedges at Perfect Plants
- Seed collections tailored to individual growing zones from Lush & Dew at Amazon
What USDA Zones Don't Tell You
A USDA zone does not determine:
- Exact sowing or planting dates
- First and last frost dates
- The length of the growing season
- Summer heat or humidity
- Rainfall and soil moisture
- Soil type, drainage or sunlight
- The effects of individual garden microclimates
USDA itself stresses that wind, moisture, humidity, soil, light, exposure and the duration of cold can all affect whether a plant survives.
When to Plant in Your Zone
Hardiness is not the same as planting time. Your hardiness zone tells you which plants are likely to survive winter, but it does not tell you exactly when to sow seeds or set out young plants. For that, local frost dates and soil temperature are more useful.
An inexpensive soil thermometer takes the guesswork out of deciding when the ground is warm enough to plant. This Yamron 4-in-1 thermometer also measures soil pH, moisture levels, and sunlight intensity. All essential information for gardeners.
What Hardiness Zones Mean for Container Plants
Keep in mind that the USDA zones are defined for planting in the ground, not containers. Soil in the ground stays warmer than soil in containers in the winter, so the zones are less reliable for plants left outdoors in containers, where the roots are more exposed to freezing temperatures. As a general rule, choose plants that are hardy to at least two zones colder than your own if you plan to leave them in containers outdoors all winter.
Tender perennials can also be grown in containers and moved into a garage, greenhouse, or other protected space before severe cold arrives. For large, heavy pots, a wheeled plant caddy makes this considerably easier. A good cost-effective pick is this two-pack of Bamworld rolling plant caddies from Amazon.
Can You Grow a Plant Outside Its Recommended Zone?
There can be a little wiggle room at the edges of hardiness zones. If you live in zone 5 and a plant is rated for zones 6 and above, your winters are officially colder than it is expected to tolerate. However, local microclimates can make a difference. A sheltered bed against a south-facing wall, for example, may stay slightly warmer than the surrounding garden and give a borderline plant a better chance of surviving.
Breathable frost cloth, like this Agfabric Floating Row Cover, can also protect tender growth during an unexpected cold snap, but it only offers short-term protection. It will not make a plant reliably winter-hardy in a climate that is substantially colder than its recommended range.
Plant Outside Your Zone with Season Extenders
Row covers trap heat and protect your plants against frost and wind, making them perfect for growing in cooler zones.
Portable mini greenhouses are great for starting seedlings indoors or protecting plants in cold zones.
Cold frames are a stylish way to protect your raised beds from frost and rain while trapping in heat.
Gardening Guides for Your USDA Zone
The USDA zone map is an invaluable starting point when choosing perennial plants. Used alongside information about summer heat, frost dates, soil, sunlight and your garden’s individual microclimates, it can help you select plants with a much better chance of success.
