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When to Plant Shiso in Monroe County, IN

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.

Monroe County, Indiana is in USDA Zone 6a. The average last spring frost is April 12 and the first fall frost is October 20, giving you a growing season of approximately 191 days.

At an elevation of 670 feet, Monroe County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Shiso during the growing season.

Monroe County, IN (Zone 6a) Moderate season
191 days
Last Spring Frost April 12
191 growing days
First Fall Frost October 20

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jun 17 – Aug 12
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Aug 16
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Mar 13 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 4

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 343 gal / 100 sq ft
Shiso needs ~915 GDD — county provides 2,912 GDD Excellent fit

Shiso Planting Timeline โ€” Monroe County, IN

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 โ€“ Mar 8
Transplant Outdoors April 26 Apr 26 โ€“ May 10
Direct Sow April 19 Apr 19 โ€“ May 10
Harvest June 21 Jun 21 โ€“ Aug 16

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 6a

Growing Season

191 days

Growing Tips for Monroe 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 Monroe County, IN?

Monroe County is in Zone 6a with an average last frost of April 12. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Monroe County, IN?

Monroe County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 12 and first fall frost is October 20.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Monroe County gardeners in Zone 6a 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 Monroe County, IN. Local conditions may vary. Last updated: April 2026.