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When to Plant Onion in Gilchrist 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.

Gilchrist County, Florida is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 27, giving you a growing season of approximately 269 days.

At an elevation of 236 feet, Gilchrist County receives approximately 53.5 inches of rainfall annually with predominantly sand soil. Summer highs average 102ยฐF, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” 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.

Gilchrist County, FL (Zone 9a) Long season
269 days
Last Spring Frost March 3
269 growing days
First Fall Frost November 27

Gilchrist County Soil Profile

Soil Type

Sand

Soil pH

5.2-5.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (137 days to spare)
Start indoors: Jan 17 Transplant: Feb 14 🍅 Harvest: May 16 – Jul 4
Recommended (50%) ✓ Fits season (129 days to spare)
Start indoors: Feb 3 Transplant: Mar 3 🍅 Harvest: Jun 2 – Jul 21
Safe Start (90%) ✓ Fits season (133 days to spare)
Start indoors: Feb 22 Transplant: Mar 22 🍅 Harvest: Jun 21 – Aug 9

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 Gilchrist County

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

Soil pH

Your soil pH (5.2โ€“5.8) is more acidic than Onion prefers (6.0โ€“7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Gilchrist 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 (1.4%). 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
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,335 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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 โ€” 2.8" 0" โ„๏ธ Dormant
Feb โ€” 2.6" 0" โ„๏ธ Dormant
Mar 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Apr 4.3" 2.3" 2" ๐Ÿ’ง Light watering
May 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Jun 4.3" 8" 0" โœ… Rainfall sufficient
Jul 4.3" 8.8" 0" โœ… Rainfall sufficient
Aug 4.3" 7.2" 0" โœ… Rainfall sufficient
Sep 4.3" 6.5" 0" โœ… Rainfall sufficient
Oct 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Nov 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Dec โ€” 2.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Gilchrist County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~2,782 GDD — county provides 7,128 GDD Excellent fit

Onion Planting Timeline โ€” Gilchrist County, FL

Onion Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 โ€“ Feb 17
Transplant Outdoors March 3 Mar 3 โ€“ Mar 17
Direct Sow February 10 Feb 10 โ€“ Mar 3
Harvest June 2 Jun 2 โ€“ Jul 21
Fall Sowing October 2 Oct 2 โ€“ Oct 16

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

269 days in Gilchrist County

Growing Tips for Onion in Gilchrist County

Direct sow Onion outdoors after March 03 in Gilchrist County when soil has warmed and frost danger has passed.

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

With summer highs reaching 102ยฐF in Gilchrist County, provide afternoon shade for Onion and water deeply in the morning.

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 Gilchrist County, FL?

Gilchrist County is in Zone 9a with an average last frost of March 3. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Gilchrist County, FL?

Gilchrist County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Gilchrist County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

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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 Gilchrist County, FL. Local conditions may vary. Last updated: April 2026.