Gardening in North Carolina

Hardiness zones in North Carolina

North Carolina covers USDA hardiness zones 6b through 9a. That is a wide span for one state, from the cool mountains in the west to the warm coast in the east. Each zone number reflects the average annual minimum winter temperature for that area. Zone 6b areas see colder winter lows than zone 9a areas near the coast. The zone number does not tell you about summer heat, rainfall, or soil type. Use it only to judge which plants can survive winter in your spot. North Carolina's zone and frost data come from readings at 185 weather stations across the state. If you garden in the mountains, plan for the colder end near 6b. If you garden near the coast, you can often push toward the warmer end near 9a. Check your exact zone before you choose perennials or shrubs meant to survive winter outdoors.

• Zone 6b
• Zone 7a
• Zone 7b
• Zone 8a
• Zone 8b
• Zone 9a

Frost dates

Frost dates in North Carolina vary widely by region and elevation. The last spring frost has come as early as March 1 in some areas. In other parts of the state, it has arrived as late as May 16. That six-week spread means a coastal gardener can often plant weeks before a mountain gardener. In fall, the first frost has arrived as early as October 4 in cooler spots. In milder coastal areas, it has held off until as late as December 22. These are the earliest and latest dates recorded across the state's weather stations, not one date for every garden. Your own last and first frost dates fall somewhere inside these ranges, depending on where you live. Wait until after your local last frost date to set out tender seedlings and warm-season crops. Protect or harvest frost-sensitive plants before your local first frost date arrives in fall. Local extension offices and long-term weather records for your county give a closer estimate than a statewide range.

Climate

Winters across North Carolina swing from cold mountain lows to mild coastal lows. The state's hardiness zones run from 6b in the coldest spots to 9a in the warmest. That range reflects differences in average winter low temperatures, not differences in rainfall or humidity. The length of the growing season also shifts sharply across the state. Some areas get as few as 140 frost-free days in a typical year. Other areas get as many as 293 frost-free days, more than double the shortest season. A grower with only 140 days has far less time to mature a long-season crop. A grower with 293 days has much more room to work with. These figures come from readings at 185 weather stations spread across North Carolina. They describe how long frost stays away and how cold winter gets. They do not describe how hot or how wet summer will be. Use your local zone and season length together to judge which plants will work in your yard. A short growing season calls for fast-maturing varieties or an early start indoors. A long growing season gives you room for slow-ripening crops and a second planting late in the year.

Season length

Growing season length varies by more than double across North Carolina. The shortest typical season runs about 140 frost-free days, found in the coldest zones. The longest typical season runs about 293 frost-free days, found in the mildest zones near the coast. That gap of over 150 days changes which crops have time to ripen before fall frost. If your season sits near the short end, choose varieties bred to mature quickly. If your season sits near the long end, you have room to start crops later. You can also plant a second round after an early harvest. Check your local frost dates to see where your own season falls inside this range.