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When to Plant Shiso in Onslow County, NC

Shiso (perilla) is a fragrant Japanese herb with large, ruffled leaves in green or purple varieties. It has a unique flavor combining mint, basil, and anise.

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 Shiso during the growing season. Clay soil retains moisture well for Shiso, 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 (119 days to spare)
Start indoors: Jan 21 Transplant: Mar 25 🍅 Harvest: May 20 – Jul 15
Recommended (50%) ✓ Fits season (116 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: May 30 – Jul 25
Safe Start (90%) ✓ Fits season (112 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jun 17 – Aug 12

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
Shiso needs ~1,050 GDD — county provides 4,235 GDD Excellent fit

Shiso Planting Timeline โ€” Onslow County, NC

Shiso Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 โ€“ Feb 14
Transplant Outdoors April 4 Apr 4 โ€“ Apr 18
Direct Sow March 28 Mar 28 โ€“ Apr 18
Harvest May 30 May 30 โ€“ Jul 25

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“70 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 8a

Growing Season

242 days

Growing Tips for Onslow County

Direct sow after last frost or start indoors. Both green and red varieties are available. Pinch tips to encourage bushiness. Self-sows prolifically; deadhead to control.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Shiso in Onslow County, NC?

Onslow County is in Zone 8a with an average last frost of March 21. Plan your Shiso 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.

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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.