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When to Plant Cilantro in Onslow County, NC

Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

Onslow County, North Carolina is in USDA Zone 8a. The average last spring frost is March 21 and the first fall frost is November 18, giving you a growing season of approximately 242 days.

At an elevation of 541 feet, Onslow County receives approximately 46.8 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90ยฐF, providing good warmth for Cilantro during the growing season. Clay soil retains moisture well for Cilantro, but amend with compost to improve drainage and prevent root rot.

Onslow County, NC (Zone 8a) Long season
242 days
Last Spring Frost March 21
242 growing days
First Fall Frost November 18

Onslow County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (147 days to spare)
Start indoors: Feb 4 Transplant: Mar 4 🍅 Harvest: Apr 15 – Jun 17
Recommended (50%) ✓ Fits season (144 days to spare)
Start indoors: Feb 14 Transplant: Mar 14 🍅 Harvest: Apr 25 – Jun 27
Safe Start (90%) ✓ Fits season (140 days to spare)
Start indoors: Mar 4 Transplant: Apr 1 🍅 Harvest: May 13 – Jul 15

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 404 gal / 100 sq ft
Cilantro needs ~875 GDD — county provides 4,235 GDD Excellent fit

Cilantro Planting Timeline โ€” Onslow County, NC

Cilantro Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 โ€“ Feb 28
Transplant Outdoors March 14 Mar 14 โ€“ Mar 28
Direct Sow March 7 Mar 7 โ€“ Mar 28
Fall Sowing September 9 Sep 9 โ€“ Sep 23
Harvest April 25 Apr 25 โ€“ Jun 27

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

40โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

242 days

Growing Tips for Onslow County

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Level Up Your Garden

Frequently Asked Questions

When should I plant Cilantro in Onslow County, NC?

Onslow County is in Zone 8a with an average last frost of March 21. Plan your Cilantro planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Onslow County, NC?

Onslow County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 21 and first fall frost is November 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Onslow County gardeners in Zone 8a 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 Onslow County, NC. Local conditions may vary. Last updated: April 2026.