Hardiness Zone for St. Petersburg, Florida

About USDA Hardiness Zones

• The United States Department of Agriculture Agricultural Research Service offers the USDA Plant Hardiness Zone map as a resource for gardeners. The map is separated into 26 zones: Zones 1 through 13 each have an "a" and "b" zone. The zones are separated by 10 degrees Fahrenheit. The temperatures are the average annual extreme minimum temperature of a particular area. The map has become the standard in the industry.

USDA Zone

• St. Petersburg, Fla., falls in USDA zone 10a. This zone experiences annual extreme cold temperatures of between 30 and 35 degrees during the winter. The only areas in the contiguous United States warmer than zone 10a include southern California, parts of Arizona and southern Florida. Choosing plants that have a maximum USDA zone lower than 10 can pose problems for plants that can't take the heat.

Other Factors

• While the USDA plant hardiness zones are the standard, other factors can influence whether or not a specific plant will grow well in your area. St. Petersburg's climate consists mostly of hot days and warm nights; mild daytime temperatures in the high-60s to mid-70s is standard even during the months of December and January. Other factors include the proximity to the ocean, sandy soils and rain throughout the year.

Gardening in St. Pete

• The mild, year-round temperatures allow you to plant during the year with a growing season that lasts from approximately February through early December. Hot fall days and warm nights can help your fall veggies escape the heat, while tropical plants thrive in the humidity -- many can be left outside year-round. The climate can be detrimental for some plants, however, as many need a cold period to go dormant.