🧅 Can I Plant Onion in Jacksonville, FL?

2026 planting guide for Zone 9a · Last frost ~February 20 · Growing season ~278 days

✅ YES — Good temps, but watch for heat — highs near 94°F

Temperature conditions are suitable for Onion. Highs near 94°F are on the warm side — make sure plants have plenty of water.

Planting window: May 18 – Jun 1
Good to go — plant now while conditions are right.
Live result based on current forecast for Jacksonville, FL · Updates every 6 hours
USDA Zone
9a
Last Spring Frost
~February 20
First Fall Frost
November 24
Growing Season
~278 days
Ideal Temp for Onion
45–75°F
Frost Risk
✅ Tolerant

Growing Onion in Jacksonville

Jacksonville's Zone 9a climate means gardening is a year-round pursuit. Winters are mild enough for cool-season crops while summers support tropical vegetables. Humidity is high June through September, which requires vigilance against fungal diseases, but the extended season easily allows two or three successions of most crops.

In Jacksonville (last frost around February 20), onion can go out around January — approximately 6 weeks before the last expected frost, making it an early-season opportunity. Starting seeds indoors 10 weeks before the last frost date gives you a significant head start.

Onion thrives between 45°F and 75°F. It tolerates temperatures as low as 28°F, making it a candidate for early spring planting before the last frost date. Expect 100–120 days from transplant to first harvest. Long season. Start early indoors or use sets.

Frequently Asked Questions

When can I plant onion in Jacksonville, FL?

In Jacksonville (last frost around February 20), onion can go out around January — approximately 6 weeks before the last expected frost, making it an early-season opportunity. For best results, start seeds indoors 10 weeks before that — giving you strong transplants ready to go out at the right time.

What is the USDA hardiness zone for Jacksonville?

Jacksonville, FL is in USDA Plant Hardiness Zone 9a. The last expected spring frost is around February 20, and the first fall frost arrives around November 24. This zone classification helps you understand which perennials survive winter and when annual vegetables can safely go outdoors.

Is it safe to plant onion outside in Jacksonville right now?

That depends on the current weather forecast. Onion needs temperatures above 28°F (ideally 45–75°F) to thrive. CanIPlant checks your real 7-day forecast and any active frost alerts to give you a live YES, NO, or WAIT answer — just enter your ZIP code.

Can I grow onion in Jacksonville 2026?

Yes — Onion grows well in Jacksonville, FL. With a Zone 9a climate and a growing season of ~278 days, Jacksonville is well-suited for cool-season crops like onion. As a frost-tolerant crop, onion can even go out a few weeks before the last frost date.

Grow Onion in Other Cities

New York, NYLos Angeles, CAChicago, ILHouston, TXPhoenix, AZPhiladelphia, PASan Antonio, TXSan Diego, CA

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