Florida · zones 8b–11a
When to plant onions in Florida.
Sow or transplant between Nov 26 to Jan 9 in a typical year, keyed to Florida's median last frost around Feb 3. A second, fall sowing fits Oct 20 to Dec 1. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Onions dates for a typical Florida season.
1 · Start indoors
Oct 15 to Nov 28
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Nov 26 to Jan 9
Keyed to the ~Feb 3 last frost. Sow 0.5" deep, 4" apart.
Fall round
Oct 20 to Dec 1
Counted back from the ~Dec 15 first frost.
Harvest
~95 days later
~0.5 lb per plant over ~1 weeks.
Florida spans more than one climate: Zone 9 is the most common zone, but the state runs 8b to 11a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
Florida growing notes
Every county in Florida grows the same day-length onion.
No latitude split here, unlike states further north
Onion bulbing triggers off day length rather than temperature, and Florida sits entirely within the short-day band from the panhandle down to the Keys, without the kind of latitude split that changes variety choice for a gardener in a longer, narrower state. Short-day types, bred to bulb once the day reaches roughly ten to twelve hours of light, are the only sound choice statewide; an intermediate or long-day type planted here bulbs too early, before the plant has built enough leaf to size up a decent bulb.
Miss that timing story and the type choice barely matters: what counts is the leaf count banked before the switch flips, since each leaf alive on the plant at that moment becomes exactly one ring inside the mature bulb. Florida's uniform short-day rule removes the guesswork on variety, but it puts all the pressure on getting transplants into the ground early enough to bank those leaves before winter ends, not on choosing among types the way a gardener further north has to.
Building leaf growth before the trigger, not after
Florida's growing window opens early enough that transplants set in fall have the entire mild winter to build leaf mass before the day-length trigger arrives, and that head start is the main advantage this state's calendar gives an onion crop over a shorter-season garden. Feed nitrogen through this leafy stage specifically, since once bulbing starts the plant shifts from building new leaves to converting what it already grew, and any nitrogen applied after that point does less for final bulb size.
A plant that goes into the ground late, after too much of that mild window has already passed, ends up bulbing on a smaller frame regardless of how well it is fed afterward. Getting transplants in as early as the season allows matters more here than almost any other single onion decision, since Florida gives more leaf-building time than most states but only if a gardener actually uses it.
Curing fights humidity on a compressed schedule
Once tops fall over, move the crop out of direct sun into somewhere shaded with air moving through it; a bulb left exposed on a bright Florida afternoon can bake hotter on the inside than the forecast high would ever imply, and that hidden heat turns the outer layers to mush before curing has a chance to work. Florida's humidity also means the standard two to three week curing estimate can run longer in a wet year, so check the neck rather than trusting a fixed number of days.
A spongy neck means more drying time is needed; once the neck snaps dry and papery under light pressure, the bulb is ready to trim and box up for storage. Florida's onion harvest also lands earlier in the calendar than a northern garden's does, thanks to that head start on leaf growth, so plan curing space accordingly rather than assuming it falls at the same time of year gardening guides written for other states describe.
In Florida: watch for
The pests that find onions here.
With about 315 frost-free days, onion, bulb spends longer in the ground here than in most of the country, which widens the window in which onion thrips can find it. Scout weekly from midseason and act on the first signs.
Silvery streaks and curled leaf tips in hot spells.
Organic fix: Insecticidal soap or neem; hang sticky traps.
Seedlings wilt; white maggots in the bulb base.
Organic fix: Float a row cover over the row; rotate beds each year.
Pale patches with fuzzy gray growth in damp weather.
Organic fix: Space for airflow, water early in the day, spray neem.
White rot
Yellowing and dieback, then wilt; fluffy white mold at the bulb base and roots so rotted the plant lifts straight out.
Organic fix: No cure once it is in the soil. Plant clean stock, never follow onions with onions, and keep infested soil off tools and boots.
Your season math: Florida gives onions about 315 frost-free days, and it needs roughly 95 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting onions in Florida: questions
When should I plant onions in Florida?+
In a typical Florida year, sow onions or set out transplants between Nov 26 to Jan 9, keyed to the state's median last frost around Feb 3. There's also a fall window: Oct 20 to Dec 1. Your exact dates shift with your ZIP code and microclimate.
When do I start onions seeds indoors in Florida?+
Start seeds inside about 6 weeks before set-out: roughly Oct 15 to Nov 28 for a typical Florida season.
What USDA zone is Florida?+
Florida spans zones 8b–11a, mostly zone 9. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many onions plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.