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When to Plant Onion in Liberty County, FL

Liberty County, Florida Zone 9a May

Your May planting checklist for Liberty County, Florida

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 4
Avg. first frost November 26
Soil temp (4") 73°F
Watering Moderate
Pest pressure High
Daylight 13.5 hrs
Looking ahead to June
  • First harvests: onion

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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.

Liberty County, Florida is in USDA Zone 9a. The average last spring frost is March 4 and the first fall frost is November 26, giving you a growing season of approximately 267 days.

At an elevation of 152 feet, Liberty County receives approximately 54.8 inches of rainfall annually with predominantly sand soil. Summer highs average 94°F, providing good warmth for Onion during the growing season. 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.

Liberty County, FL (Zone 9a) Long season
267 days
Last Spring Frost March 4
267 growing days
First Fall Frost November 26
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Liberty County Soil Profile

Soil Type

Sand

Soil pH

4.9-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (133 days to spare)
Start indoors: Jan 22 Transplant: Feb 19 🍅 Harvest: May 21 – Jul 9
Recommended (50%) ✓ Fits season (127 days to spare)
Start indoors: Feb 4 Transplant: Mar 4 🍅 Harvest: Jun 3 – Jul 22
Safe Start (90%) ✓ Fits season (127 days to spare)
Start indoors: Feb 26 Transplant: Mar 26 🍅 Harvest: Jun 25 – Aug 13

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Liberty County

How your county's soil matches Onion's growing requirements.

Soil pH

Your soil pH (4.9–6.1) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Liberty County warms quickly in spring but drains fast. Onion will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Onion.

Organic Matter

Organic matter is low (1.7%). Add 2-3 inches of compost before planting Onion.

How to Plant Onion

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,041 gal / 100 sq ft

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 2.3" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 8" 0" ✅ Rainfall sufficient
Jul 4.3" 8" 0" ✅ Rainfall sufficient
Aug 4.3" 7.6" 0" ✅ Rainfall sufficient
Sep 4.3" 7.9" 0" ✅ Rainfall sufficient
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Liberty County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Onion Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Onion needs ~2,152 GDD — county provides 5,473 GDD Excellent fit

Onion Planting Timeline — Liberty County, FL

Onion Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors March 4 Mar 4 – Mar 18
Direct Sow February 11 Feb 11 – Mar 4
Harvest June 3 Jun 3 – Jul 22
Fall Sowing October 1 Oct 1 – Oct 15

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow
April
May
June Harvest
July Harvest
August
September
October Fall Sowing
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

267 days in Liberty County

Growing Tips for Onion in Liberty County

Direct sow Onion outdoors after March 04 in Liberty County when soil has warmed and frost danger has passed.

Sandy soil in Liberty County dries quickly — mulch Onion with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

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

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Liberty County, FL?

Liberty County is in Zone 9a with an average last frost of March 4. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Liberty County, FL?

Liberty County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 4 and first fall frost is November 26.

🌱

Your Liberty County Garden Planner — Free

A 24-page printable planner built for Liberty 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Liberty County, FL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.