Florida planting calendar

When to plant onions in Florida — sow, transplant & harvest dates

Florida is mostly USDA zone 9b (range 8a-11b). Dates below are derived from onions's frost tolerance and Florida's frost window — not generic national averages.

Onions planting timetable for Florida

Stage	When in Florida	Anchor
Direct-sow / set out (main)	October — February	Grown through the cool season, not summer
Shoulder sowing	September and again late February	Avoid germinating into summer heat
First harvest	~110 days after sowing (late autumn through spring)	110-day crop

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Florida's climate shifts the onions dates

Florida flips the calendar: its winter is the productive onions season while northern states are frozen, and its summer is the off-season. Florida is the warmest state in the contiguous US, with subtropical to tropical conditions. The growing constraint is summer heat, humidity, and rain — not cold.

Onions are day-length sensitive: long-day varieties (zones 1–6) begin bulbing when days exceed 14 hours, short-day types (zones 7–10) bulb at 10–12 hours, and intermediate-day varieties span zones 5–6. Start seeds indoors 10–12 weeks before the last spring frost and transplant out 4–6 weeks before it — young onion seedlings tolerate frost down to about -6 °C once hardened off. In zones 8–10 a second planting from sets in autumn is common, overwintering for an early-summer harvest.

Frost-risk note

Light frost in the western Panhandle near Tallahassee (zone 8a) only nips the outer leaves — heat, not cold, ends the crop.

Regional variation within Florida

the Florida Keys (zone 11b) can sow earliest in autumn and latest into late winter; the western Panhandle near Tallahassee (zone 8a) has a slightly shorter, frost-bracketed window.

Miami — USDA zone 11a
Orlando — USDA zone 10a
Tampa — USDA zone 10a
Jacksonville — USDA zone 9a
Tallahassee — USDA zone 8b

What else to plant in Florida around then

The same cool window suits other greens, brassicas, peas, carrots, and radishes — fill beds October through February.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 10-35 °C (50-95 °F).
Spacing: 4-6 inches (10-15 cm) between plants.
Days to harvest: ~110 days from planting out.

Frequently asked questions

When is the best time to plant onions in Florida?

In Florida (mostly USDA zone 9b), grow onions as a cool-season crop: direct-sow from October through February, harvest ~110 days later, and skip summer entirely — heat above 24 °C bolts it. Onions are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is Florida?

Most of Florida sits in USDA hardiness zone 9b, with the state spanning roughly 8a-11b from the western Panhandle near Tallahassee (zone 8a) to the Florida Keys (zone 11b). The last spring frost averages late February (north) to no frost (south) and the first fall frost mid-December (north) to no frost (south).

Can you grow onions in Florida?

Yes. Florida's dominant zone 9b supports onions — the key is timing. Onions are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across Florida?

the Florida Keys (zone 11b) can sow earliest in autumn and latest into late winter; the western Panhandle near Tallahassee (zone 8a) has a slightly shorter, frost-bracketed window.

What else can I plant in Florida around the same time?

The same cool window suits other greens, brassicas, peas, carrots, and radishes — fill beds October through February.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.