Which garden zone am I in? Find your USDA plant hardiness zone.

When you go to buy plants, you may see labels that say “Zones 3-7” or similar numbers. These references indicate the plant hardiness zones where specific greenery will thrive.

Understanding your garden area is key to selecting plants suitable for your region’s climate so that your garden blooms year-round. Knowing your zone can help you make informed decisions that promote the health and longevity of your outdoor plants.

What is a garden zone?

A garden zone, also called a plant hardiness zone, is a geographically defined area that helps gardeners determine which plants are most likely to thrive in the region’s climate. The USDA categorizes these zones based on the area’s average minimum temperatures. The USDA Plant Hardiness Zone Map divides North America into 13 zones based on average annual minimum winter temperature.

In 2023, the USDA released a updated hardiness zone map in response to the effects of climate change. The updated map indicated a northward shift in the zones, reflecting the changing conditions.

Why are garden zones important?

Garden zones provide essential information about the climate in your area, especially the coldest temperatures. By selecting plants suitable for your area, you minimize the risk of winter damage, ensure better survival rates and reduce replacement costs.

Knowing your zone also helps plan your planting schedule, including optimal times for sowing and transplanting. Many garden supplies and nurseries offer tailored advice and products based on these zones, making it easier to find the right guidance and supplies.

What does heat zone mean?

Some plant labels also indicate a heat zone. A heat zone refers to a geographic area defined by the American Horticultural Society (AHS) based on the average number of days per year that a region experiences temperatures above 30°C. These zones are specifically designed as a high temperature counterpart to the USDA Plant Hardiness Zones, which are based on minimum cold temperatures.

The AHS installation heat zone map identifies 12 zones, which indicate regions where plants are exposed to high temperatures that can affect their growth, survival and flowering times. Understanding heat zones is critical for gardeners to select plants that can tolerate local heat conditions, preventing problems like wilt or sunscald, especially during the warmer parts of the year. Using this information, along with the hardiness zone, will help you choose the right plants that will do well in your region.

Step-by-step guide to finding your garden zone

Visit the USDA plant hardiness zone map:

This card is the most widely used source for determining garden zones in the United States. The garden zone map provides detailed information about the extreme temperatures in each zone.

Enter your zip code:

Enter your zip code to find out your exact zone. This method is simple and eliminates the need to interpret the color-coded map yourself. The difference between each hardiness zone is 10 degrees Fahrenheit and is usually divided into two subzones, “a” and “b”, which have a difference of 5 degrees Fahrenheit.

Find out what the zones mean:

Each zone corresponds to a range of minimum winter temperatures. For example, Zone 3 may have temperatures ranging from -40 to -30°F, while Zone 9 may only drop to 20-30°F. Understanding these ranges will help you select plants suitable for your region’s climate.

Use the zone information when purchasing plants:

Nursery tags and seed packets often contain zone information. To improve the survival and growth rate of the plants you purchase, make sure they are suitable for your zone. When selecting plants, also consider the heat zone of your region.

Adjusting for microclimates:

Keep in mind that microclimates in your garden, such as shady areas or windy areas, can affect the viability of certain plants, even within your zone.

How to select plants based on your garden zones

When selecting plants for your garden, it is essential to consider both the USDA Plant Hardiness Zone and the AHS Heat Zone listed on the plant label. Most plant tags and plant information on plant websites list hardiness zones, and many will also list heat zone. Matching these zones to your local climate can help you determine whether a plant is likely to thrive in your garden. For example, if you live in USDA Zone 8 and AHS Heat Zone 7, look for plants tagged in those zones to ensure they are well suited to the winter cold and summer heat of your region.