Georgia sits at 33.63 degrees north, measured at Atlanta, and the longest day of the year there brings 14 hours and 14 minutes of daylight. That number rules out long-day onions entirely and points growers toward two groups instead: short-day and intermediate-day varieties, the only ones built to bulb before that day length maxes out.
The short answer for Georgia
An onion doesn’t care how hot your July is. What flips the switch from leaf-growth to bulb-growth is the number of daylight hours it’s getting, and at Atlanta’s latitude, that ceiling is 14 hours and 14 minutes on the summer solstice. Short-day varieties start bulbing once the day reaches roughly 12 hours, so they trigger early and finish well within what Georgia offers. Intermediate-day types wait for something closer to 12 to 14 hours, and Georgia’s summer daylight just about covers that range too. That’s why both groups work here, while the long-day types built for 14 to 16 hours are asking for a day length Georgia’s sun never delivers.
Twelve documented varieties on this site have a published latitude range that covers 33.63N, which means Georgia sits inside their working zone rather than at the edge of it. Among the short-day types: Texas Grano 1015Y, Vidora, and Red Sensation are the ones with pages of their own here; Gabriella, Madalyn, Red Rock, and White Castle also cover this latitude but don’t have dedicated pages on this site yet. Among the intermediate-day types, Candy, Elsye, Expression, Scout, and Sierra Blanca all list 33.63N comfortably within their range.
That’s a real spread to choose from, sweet short-day storage onions on one end, firmer intermediate-day types on the other. Whichever direction a gardener leans, the deciding factor stays the same: does the variety’s published range include this latitude, or is it asking for a day length that never arrives here.
What will not work here
The mistake isn’t planting the wrong variety and getting a smaller onion. It’s planting the wrong variety and getting no onion at all. Long-day types are bred for northern summers where the day stretches to 14, 15, even 16 hours. Georgia’s ceiling stops at 14 hours and 14 minutes, and most long-day varieties need more than that to ever start swelling a bulb. Plant one anyway and the result follows a predictable pattern: the plant puts up leaves all spring, keeps putting up leaves all summer because it’s still waiting for a day length that’s never coming, and then rots in the ground once the season turns. No small onion. No onion.
Thirteen varieties documented on this site fall into that category for Georgia, each one published for latitudes north of where the state’s daylight tops out:
- Ailsa Craig (38-60N): needs day lengths well beyond Georgia’s summer maximum
- Barolo (38-55N): bred for northern latitudes, will only make leaves here
- Blush (38-55N): same ceiling problem, no bulb trigger reached
- Frontier (40-50N): far north of Georgia’s daylight range
- New York Early (38-50N): despite the name, too far north for this state
- Patterson (38-55N): a storage classic, but not one for Georgia gardens
- Powell (43-47N): a narrow northern band, well outside Georgia’s reach
- Red Carpet (40-45N): requires day length Georgia never provides
- Red Long of Florence (38-50N): an intermediate-day type still too far north
- Redwing (43-65N): built for far-northern and Canadian summers
- Rossa di Milano (38-50N): same story, wrong hemisphere of the day-length scale
- Safrane (42-50N): needs a longer summer day than Georgia offers
- Talon (42-50N): another northern long-day type, skip it here
None of these are marginal choices that might struggle. They’re varieties calibrated for a day length Georgia’s summer solstice doesn’t reach, and the plant has no way around that.
What changes across Georgia
Georgia isn’t a single point on the map. The state runs from around 30.3 degrees north near the Florida line to close to 35 degrees north at the Tennessee border, a spread of nearly five degrees of latitude. The figures in this article come from Atlanta, at 33.63N, which sits closer to the northern half of the state than the southern half. A gardener in Savannah or Valdosta is working with slightly less summer daylight than Atlanta gets; a gardener up near Dalton or Blue Ridge is working with slightly more.
| Location | Approx. latitude | Day length vs. Atlanta | What it changes |
|---|---|---|---|
| North Georgia (near TN border) | ~35.0N | Slightly longer summer day | Edges toward the upper bound for some intermediate-day varieties; blurred-zone types like Cabernet or Calibra (both 35-45N) become worth testing |
| Atlanta (reference city) | 33.63N | 14 h 14 (baseline) | Squarely inside both short-day and intermediate-day ranges |
| South Georgia (near FL border) | ~30.3N | Slightly shorter summer day | Firmly short-day territory; short-day types bulb even earlier here |
For most of the state, that difference doesn’t change the recommendation. Short-day and intermediate-day varieties both work from the coastal plain to the Piedmont. But a reader gardening near the Tennessee line should treat the 12 varieties listed above as the safe core, and view the blurred-zone types (Bridger, Cabernet, Calibra, Monastrell, Red Long of Tropea, Walla Walla Sweet) as worth a trial rather than a guarantee, since their published ranges only start where north Georgia’s daylight approaches.
Sweet now, or onions that last
Georgia’s day length pushes gardeners toward short-day and intermediate-day onions, and that choice comes with a trade-off that has nothing to do with luck. The compounds that make an onion sharp, the volatile sulfur molecules responsible for the bite and the tears, are the same compounds that protect the bulb once it’s out of the ground. University of Missouri Extension puts it plainly: sweet onions do not store as well as the more pungent types, because pungency and shelf life come from the same chemistry.
Short-day varieties, the ones best suited to Georgia’s lower latitude, tend to run sweeter and milder. That’s a direct result of lower sulfur content, the same trait that makes them better fresh off the counter and worse in a root cellar come February. Georgia’s own Vidalia onions, grown under this exact short-day framework, are the textbook example: prized for eating within a few months of harvest, not for lasting through winter.
What that means for a Georgia pantry is straightforward. A short-day crop harvested in late spring or early summer is best used, given away, or frozen within a few months. By March, most of it is gone or going soft, because the chemistry that would have preserved it simply isn’t there in the same concentration as in a northern long-day onion. A gardener who wants both, something to eat now and something to store through winter, gets more mileage from intermediate-day varieties like Candy or Scout, which trade a little sweetness for a longer shelf life without needing a day length Georgia can’t provide.
Checking this against your own garden
Every figure in this article comes from Atlanta’s exact coordinates, and Georgia is wide enough that a garden 150 miles away can sit on meaningfully different daylight and frost timing. Before ordering seed or sets, it’s worth confirming a few things locally rather than assuming Atlanta’s numbers apply everywhere in the state.
- Look up your own latitude if you’re gardening well north or south of Atlanta, since even a degree or two shifts where you fall relative to the variety ranges listed above
- Check your area’s average first and last frost dates, which determine planting windows independent of the day-length question
- Contact your county’s UGA Cooperative Extension office, which tracks local planting calendars and can confirm which onion groups perform well in your specific county
- Ask about local trial results for blurred-zone varieties if you’re near the Tennessee border, since published latitude ranges are a starting point, not a guarantee for your exact spot
- Note your garden’s microclimate, since a low-lying frost pocket or an unusually sheltered spot can shift effective timing by a week or two even within the same county