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When to Plant Onion in Geneva County, AL

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.

Geneva County, Alabama is in USDA Zone 8a. The average last spring frost is March 15 and the first fall frost is November 13, giving you a growing season of approximately 243 days.

At an elevation of 224 feet, Geneva County receives approximately 52.6 inches of rainfall annually with predominantly clay loam soil. Summer highs average 97ยฐF, so Onion may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Onion, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Geneva County, AL (Zone 8a) Long season
243 days
Last Spring Frost March 15
243 growing days
First Fall Frost November 13

Geneva County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (104 days to spare)
Start indoors: Jan 30 Transplant: Mar 6 🍅 Harvest: Jun 5 – Jul 24
Recommended (50%) ✓ Fits season (103 days to spare)
Start indoors: Feb 8 Transplant: Mar 15 🍅 Harvest: Jun 14 – Aug 2
Safe Start (90%) ✓ Fits season (94 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jul 11 – Aug 29

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 Geneva County

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

Soil pH

Your soil pH (5.7โ€“6.7) overlaps with Onion's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The clay loam soil in Geneva County is excellent for Onion โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Onion.

How to Plant Onion

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

Fall planting: Sow 10 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
0.1″/week
Watering frequency Only during dry spells
Season total 197 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 โ€” 4.5" 0" โ„๏ธ Dormant
Feb โ€” 4" 0" โ„๏ธ Dormant
Mar 4.3" 5.3" 0" โœ… Rainfall sufficient
Apr 4.3" 4" 0.3" ๐Ÿ’ง Light watering
May 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Jun 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Jul 4.3" 5.7" 0" โœ… Rainfall sufficient
Aug 4.3" 5.3" 0" โœ… Rainfall sufficient
Sep 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Oct 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Nov 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Dec โ€” 4.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Geneva 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 ~2,389 GDD — county provides 5,528 GDD Excellent fit

Onion Planting Timeline โ€” Geneva County, AL

Onion Planting Calendar

Activity When Date Range
Start Indoors February 8 Feb 8 โ€“ Feb 22
Transplant Outdoors March 15 Mar 15 โ€“ Mar 29
Direct Sow March 1 Mar 1 โ€“ Mar 22
Harvest June 14 Jun 14 โ€“ Aug 2
Fall Sowing September 4 Sep 4 โ€“ Sep 18

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

243 days in Geneva County

Growing Tips for Onion in Geneva County

Direct sow Onion outdoors after March 15 in Geneva County when soil has warmed and frost danger has passed.

With Geneva County's clay soil (30% clay), work in 3-4 inches of compost before planting Onion. Avoid tilling when soil is wet to prevent compaction.

With summer highs reaching 97ยฐF in Geneva 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 Geneva County, AL?

Geneva County is in Zone 8a with an average last frost of March 15. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Geneva County, AL?

Geneva County, Alabama is in USDA Hardiness Zone 8a. The average last spring frost is March 15 and first fall frost is November 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Geneva County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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