Gardening in Georgia: zones, frost dates and when to plant

Mountains, Piedmont and Coastal Plain

NOAA’s state climate summary describes Georgia as having long, hot, humid summers and short, usually mild winters. Elevation runs from sea level on the coast to over 4,700 feet in the Blue Ridge of the northeast, and summer heat varies across the state accordingly. Inland cities such as Macon and Columbus average around 20 days a year above 95°F. Atlanta averages about 7, and the mountains less than one. Very warm nights are rare in the mountains and common on the southeast coast around Brunswick.

UGA Extension’s Vegetable Garden Calendar (Circular 943) uses middle Georgia as its baseline, a belt across the state from Columbus through Macon to Augusta. From there:

• South Georgia: in the extreme south, spring planting can begin up to 2 to 3 weeks earlier and fall planting can run up to 2 weeks later.
• North Georgia: spring planting runs 1 to 3 weeks later as you move north through the mountain counties, and fall planting comes about 2 weeks earlier.

Match these shifts to the frost dates for your city above, and adjust for the weather each year. UGA notes that no season follows the average exactly.

What limits Georgia gardens

Two very different soils. UGA horticulturists describe north Georgia’s red Piedmont clay as holding too much water in a rainy winter, which can suffocate roots, and baking hard in summer if it isn’t amended. The sandy soils of the Coastal Plain in the south are easier to work in winter. In summer, though, they need more irrigation and about twice the fertilizer that gardens farther north need. UGA’s planting chart adds that in heavy clay, seeds should be planted shallowly when there’s enough moisture.

Organic matter burns off fast. UGA advises mixing 4 to 6 inches of organic matter into ground that has never been gardened. Plan to add more every year, because Georgia’s heat and humidity break it down quickly.

Humidity and disease. With more than 50 inches of rain a year and high humidity, Georgia gardens face heavy insect and fungal disease pressure. UGA’s advice is to water early in the morning so leaves dry quickly, use soaker hoses or drip tape to keep foliage dry, and mulch with straw, leaves, compost or pine straw to a settled depth of 2 to 4 inches.

Nematodes and tough weeds. UGA warns that nematodes must be dealt with before planting, not after. It also advises avoiding sites with a history of nutsedge or bermudagrass.

What UGA Extension recommends

UGA Extension’s Vegetable Gardening in Georgia (Circular 963) is the state’s core home-garden reference. Its Vegetable Planting Chart gives spring and fall planting windows, spacing and recommended varieties for each crop. Circular 943 describes the two main planting seasons. Spring planting runs from March through May for a June and July harvest. Fall planting runs from mid-July through September, with harvest from October into December.

Varieties named in the chart include:

• Tomatoes: ‘Celebrity’, ‘BHN 444’, ‘Amelia’ and ‘Mountain Pride’, with a fall planting window as well as a spring one
• Collards: ‘Georgia Southern’, ‘Blue Max’ and ‘Hevi-Crop’
• Okra: ‘Clemson Spineless’ and ‘Annie Oakley II’
• Southern peas: ‘Zipper Cream’ and ‘Mississippi Silver’
• Sweet potatoes: ‘Georgia Red’ and ‘Centennial’
• Bulb onions: ‘Savannah Sweet’ and ‘Grano’

UGA calls these a few proven choices among many. It suggests trying new varieties on a small scale first.

Circular 963’s site advice is strict about sun: 8 to 10 hours a day. Put tall crops on the north or west side so they don’t shade shorter ones, and keep a garden map so you can rotate crops each year. In dry weather, a thorough soaking once a week is usually enough on heavier soils, while sandy soils need water more often.

Soil testing

Run a soil test through your county Extension office several months before planting. UGA recommends pH 6.0 to 6.5 for most vegetables and 5.0 to 6.0 for Irish potatoes. If the soil is acidic, mix the recommended lime in during soil preparation. Then fertilize according to the test results, with a second feeding or side-dressing once crops start to mature.