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When to Plant Onion in Nash County, NC

Nash County, North Carolina Zone 8a May

Your May game plan for Nash County, North Carolina

Your Nash County, North Carolina garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 28
Avg. first frost November 6
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 13.9 hrs
  1. Indoor seed-starting week for onion

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

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.

Nash County, North Carolina is in USDA Zone 8a. The average last spring frost is March 28 and the first fall frost is November 6, giving you a growing season of approximately 223 days.

At an elevation of 657 feet, Nash County receives approximately 45.3 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°F, 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.

Nash County, NC (Zone 8a) Long season
223 days
Last Spring Frost March 28
223 growing days
First Fall Frost November 6

Nash 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 (86 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: Jun 20 – Aug 8
Recommended (50%) ✓ Fits season (83 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: Jun 27 – Aug 15
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 15 – Sep 2

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 Nash County

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

Soil pH

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

Soil Texture

The clay loam soil in Nash County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). 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
0.2″/week
Watering frequency Only during dry spells
Season total 291 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 4.2" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 4.3" 4.1" 0.2" 💧 Light watering
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 4.3" 3.8" 0.5" 💧 Light watering
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Nash 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 ~2,074 GDD — county provides 4,404 GDD Excellent fit

Onion Planting Timeline — Nash County, NC

Onion Planting Calendar

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

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

223 days in Nash County

Growing Tips for Onion in Nash County

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

With Nash County's clay soil (31% 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 Nash County, NC?

Nash County is in Zone 8a with an average last frost of March 28. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Nash County, NC?

Nash County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 28 and first fall frost is November 6.

🌱

Your Nash County Garden Planner — Free

A 24-page printable planner built for Nash County (Zone 8a). 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 Nash County, NC. 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.