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When to Plant Onion in Lenoir County, NC

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.

Lenoir County, North Carolina is in USDA Zone 7b. The average last spring frost is March 28 and the first fall frost is November 7, giving you a growing season of approximately 224 days.

At an elevation of 480 feet, Lenoir County receives approximately 49.8 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92ยฐF, providing good warmth for Onion during the growing season. Clay soil retains moisture well for Onion, but amend with compost to improve drainage and prevent root rot.

Lenoir County, NC (Zone 7b) Long season
224 days
Last Spring Frost March 28
224 growing days
First Fall Frost November 7

Lenoir County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: Jun 20 – Aug 8
Recommended (50%) ✓ Fits season (84 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: Jun 27 – Aug 15
Safe Start (90%) ✓ Fits season (83 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 13 – Aug 31

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 Lenoir County

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

Soil pH

Your soil pH (5.7โ€“6.3) overlaps with Onion's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 132 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€” 3.5" 0" โ„๏ธ Dormant
Mar 4.3" 4.5" 0" โœ… Rainfall sufficient
Apr 4.3" 4" 0.3" ๐Ÿ’ง Light watering
May 4.3" 4.6" 0" โœ… Rainfall sufficient
Jun 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
Jul 4.3" 4.7" 0" โœ… Rainfall sufficient
Aug 4.3" 4.7" 0" โœ… Rainfall sufficient
Sep 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Oct 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Nov 4.3" 4.3" 0" โœ… Rainfall sufficient
Dec โ€” 4.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Lenoir 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 ~1,995 GDD — county provides 4,256 GDD Excellent fit

Onion Planting Timeline โ€” Lenoir County, NC

Onion Planting Calendar

Activity When Date Range
Start Indoors February 21 Feb 21 โ€“ Mar 7
Transplant Outdoors March 28 Mar 28 โ€“ Apr 11
Direct Sow March 14 Mar 14 โ€“ Apr 4
Harvest June 27 Jun 27 โ€“ Aug 15
Fall Sowing August 29 Aug 29 โ€“ Sep 12

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August Fall Sowing 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 7b

๐Ÿ“† Growing Season

224 days in Lenoir County

Growing Tips for Onion in Lenoir County

Direct sow Onion outdoors after March 28 in Lenoir County when soil has warmed and frost danger has passed.

With Lenoir County's clay soil (27% clay), work in 3-4 inches of compost before planting Onion. Avoid tilling when soil is wet to prevent compaction.

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 Lenoir County, NC?

Lenoir County is in Zone 7b with an average last frost of March 28. Plan your Onion planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lenoir County, NC?

Lenoir County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is March 28 and first fall frost is November 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lenoir County gardeners in Zone 7b 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 Lenoir County, NC. Local conditions may vary. Last updated: April 2026.