Planting Zones
By Sherril Steele-Carlin
Do you know your zone, or are you zone challenged? Every area of the country has different growing conditions, so horticultural experts have established planting zones that break the nation (and the world) into planting zones. If you know your local zone, you can find the plants that are the best suited for your growing conditions, while avoiding those that will not do well in your area.
For example, if you live in the arid desert Southwest, plants that need a lot of water and cool days may not thrive in your garden, but chile peppers and many types of squashes will. Most plants and seeds sold today will tell you what zones they will grow best in, and there are many zone maps available to show you what zone you live in, and what plants will do best in your particular area.
Ten Zones
There are 10 zones in the United States, which vary in winter temperatures from 30 to 40 degrees F. above zero, (Zone 10, the most temperate), to 50 degrees F. below zero (Zone 1). There are many sources online to find your particular zone. Some are listed by state, some by city or zip code, and some by plants that will grow in your zones. Before you plant a garden or landscape, especially if you've just relocated to a new area, you should check out the planting zone, and the plants that are recommended for it.
"Micro" Zones
Some climates may have "micro" zones, or areas that differ slightly from the surrounding areas because of geographic or climate conditions. For example, homes and gardens in the same neighborhood can receive differing amounts of shade, and can be more sheltered from chilling winds, and so their gardens may be "micro" climates, and support different plants than even neighbors down the street. Thus, even though you know your overall zone, your yard may be different from your neighbors, so experimenting with some plants on the edge of your zone can sometimes produce great results.
Origins of the Zones
The zone maps were created in 1960 to help gardeners recognize their climate zones, and which plants will grow the best in each zone. Henry T. Skinner, the second director of the U.S. National Arboretum, created the original map. He worked with horticultural experts around the country to develop the zones that include climate information, winter chill factors, and rainfall, among other factors that influence a plant's hardiness.
The map was revised in the 1990s because of better weather information available, and continued new species of plants showing up. Today, the zone map is the gardener's best friend. Always consult your local zone map if you are unsure just what plants will thrive in your area. Most local garden shops can help you with zones in your area, and there are several online sources below. So, know your zone, and you'll never plant the wrong plants in your garden!