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When to Plant Shiso in Huron County, MI

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.

Huron County, Michigan is in USDA Zone 5b. The average last spring frost is May 9 and the first fall frost is October 10, giving you a growing season of approximately 154 days.

At an elevation of 1,170 feet, Huron County receives approximately 41.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Shiso to ensure they mature before fall.

Huron County, MI (Zone 5b) Moderate season
154 days
Last Spring Frost May 9
154 growing days
First Fall Frost October 10

Huron County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Mar 13 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 4
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 21 Transplant: May 23 🍅 Harvest: Jul 18 – Sep 12
Safe Start (90%) ✓ Fits season (35 days to spare)
Start indoors: Apr 3 Transplant: Jun 5 🍅 Harvest: Jul 31 – Sep 25

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Shiso needs ~735 GDD — county provides 1,886 GDD Excellent fit

Shiso Planting Timeline โ€” Huron County, MI

Shiso Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 โ€“ Apr 4
Transplant Outdoors May 23 May 23 โ€“ Jun 6
Direct Sow May 16 May 16 โ€“ Jun 6
Harvest July 18 Jul 18 โ€“ Sep 12

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
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 5b

Growing Season

154 days

Growing Tips for Huron 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 Huron County, MI?

Huron County is in Zone 5b with an average last frost of May 9. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Huron County, MI?

Huron County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 9 and first fall frost is October 10.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Huron County gardeners in Zone 5b 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 Huron County, MI. Local conditions may vary. Last updated: April 2026.