When to plant Onion in Union County, FL
Aim to plant Onion in Union County on or after February 8; the window stays open through March 1. Union County's 271-day frost-free season gives you plenty of room for a spring and fall cycle. A second sowing from October 2 to October 16 extends the harvest into fall.
When to Plant Onion in Union County, FL
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
Union County, Florida is in USDA Zone 9a. The average last spring frost is March 1 and the first fall frost is November 27, giving you a growing season of approximately 271 days.
At an elevation of 360 feet, Union County receives approximately 60.6 inches of rainfall annually with predominantly sand soil. Summer highs average 96°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.
Union County Soil Profile
Soil Type
Sand
Soil pH
5.2-6
Drainage
Well Drained
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.1" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Apr | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| May | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 8.1" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 10" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 9" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 7.2" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Dec | — | 2.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — Union County, FL
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 1 | Feb 1 – Feb 15 |
| Transplant Outdoors | March 1 | Mar 1 – Mar 15 |
| Direct Sow | February 8 | Feb 8 – Mar 1 |
| Harvest | May 31 | May 31 – Jul 19 |
| Fall Sowing | October 2 | Oct 2 – Oct 16 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 9a
📆 Growing Season
271 days in Union County
Growing Tips for Union County
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Union County, FL?
Union County is in Zone 9a with an average last frost of March 1. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, FL?
Union County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 1 and first fall frost is November 27.
When should I plant Onion in Union County, FL?
In Union County, FL, plant Onion after the last frost (around March 1) and before the first frost (around November 27). Best results when soil holds above 50°F.
What growing zone is Union County, FL for Onion?
Union County sits in USDA Zone 9a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Union County's climate?
Yes — Onion grows well in Union County's temperate climate. Union County averages a 271-day frost-free season, with last frost around March 1 and first frost around November 27.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.