The success of your garden relies heavily on selecting the right plants for your planting zone. And since no one wants to waste their time and effort in the garden, understanding what your gardening zone is and selecting the plants that will thrive in that zone is essential for success.
For example, you won’t find tropical plants, such as a hibiscus or orange trees, growing in Alaska. Plants have adapted to grow in certain zones that provide them with the temperature, sunlight, moisture, soil and just the right ratio of cold and hot to meet their growing needs.
This is the number one question you need to answer before planting anything. Look on the hardiness map and locate your state. The color-coding will tell you what hardiness zone your state is in and that will enable you to select plants that will thrive, instead of die, in your garden.
Planting Zone Numbers
The zone numbers are the way various climates are delineated for the benefit of the gardener. Hardiness zone numbers start in Alaska at 1a and increase going across the map as the climate become warmer.
The hardiness zone map ends in Puerto Rico, warmest climate with the highest zone number, at 13b. The map is based on the average annual minimum winter temperature, divided into 10-degree Fahrenheit zones. Flowers, trees and shrubs that thrive in the hot humidity of Puerto Rice would not survive one growing season in Alaska, and vise verse.
One Number Difference
Look at the map carefully before making plant choices. Your state may have more than one planting zone and have numbers than range from 7a to 8b, like the state of Georgia. That difference of one number can mean failure in the garden even though it’s one state.
Click to open full Plant Hardiness map of Georgia
The hardiness zone number of 7a is in the mountainous region of upper Georgia, while the 8b zone is in lower Georgia along the coastline line. The mountains are cooler year around, with freezing temperatures and snow in the winter.
The coastline would enjoy plenty of heat and sun most of the year with temperatures rarely going below freezing, so it’s easy to see why plants would thrive in one part of Georgia and not in the other.
Soil and Rain Fall
There are other differences, beside climate, that the zone hardiness map will alert you too, and that is soil and rain fall differences. The same state doesn’t always have the same soil throughout.
Let’s go back to the example of Georgia, the coastal land would contain a lot of sand, the mountains would have fertile, well-draining, rocky soil and in-between the two state lines is red clay soil that is compacted, non-fertile and drains poorly, plus there is swamp land in the lower portion of the state. Plants must be carefully selected for the particular soil in your growing zone.
The same state will also receive different amounts of rain fall. To make garden maintenance easier and to protect natural resources, select plants that are drought tolerant for dry regions that receive little annual rain fall and plants that thrive in moist soil for growing zones that have a higher-than-average rain fall.
Seed Packets and Plant Labels
Once you have determined the gardening zone you live in, it’s time to read the instructions on seed packets and plant labels. Both will provide valuable information regarding the plant’s needs and include the hardiness zone in which it will grow best.
Some things can be modified in your garden to enable certain plants to grow in your garden even if it is slightly out-of-zone. Soil is easy to amend to meet plant needs and a greenhouse or cold frame are other methods that will allow a gardener to grow a wider variety of plants and/or extend the growing season.
When in doubt about which plants or trees will grow best in your growing zone, visit your local garden supply center for plants and advice. Seed companies that sell their products via catalog will ship their plants and seeds across the country, but that does not mean the plants or seeds are adapted to be grown in your gardening zone.
Use the popular seed catalogs as ‘wish books’ to help decide what you would like to grow in your home garden and to discover plants that are adapted for growth in your area, but when it’s time to purchase plants or trees, it’s best to buy from a local source.
The USDA Planting Zone Hardiness Map
The USDA planting zone hardiness map provides us with guidelines as to what will, or will not, grow in the area in which we live.
The hardiness map has been modified recently with a 5-degree Fahrenheit change for both cold and warm climates. Be sure you’re viewing an updated version of the planting zones and select plants accordingly for garden success.
For your convenience we’ve added an easily accessible interactive map below. Simply click on any state to open its printable USDA Planting Zone map.