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When to Plant Shiso in Union County, GA

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.

Union County, Georgia is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 23, giving you a growing season of approximately 195 days.

At an elevation of 175 feet, Union County receives approximately 61.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93ยฐF, 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. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shiso root diseases.

Union County, GA (Zone 7a) Moderate season
195 days
Last Spring Frost April 11
195 growing days
First Fall Frost October 23

Union County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🍅 Harvest: Jun 9 – Aug 4
Recommended (50%) ✓ Fits season (69 days to spare)
Start indoors: Feb 21 Transplant: Apr 25 🍅 Harvest: Jun 20 – Aug 15
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Mar 15 Transplant: May 17 🍅 Harvest: Jul 12 – Sep 6

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
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Shiso needs ~1,185 GDD — county provides 3,851 GDD Excellent fit

Shiso Planting Timeline โ€” Union County, GA

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 21 Feb 21 โ€“ Mar 7
Transplant Outdoors April 25 Apr 25 โ€“ May 9
Direct Sow April 18 Apr 18 โ€“ May 9
Harvest June 20 Jun 20 โ€“ Aug 15

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

Month-by-Month Timeline

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

Growing Season

195 days

Growing Tips for Union 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 Union County, GA?

Union County is in Zone 7a with an average last frost of April 11. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, GA?

Union County, Georgia is in USDA Hardiness Zone 7a. The average last spring frost is April 11 and first fall frost is October 23.

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Plan Your Garden with Confidence

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