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When to Plant Shiso in Ogemaw County, MI

Ogemaw County, Michigan Zone 5a May

May to-do list for Ogemaw County, Michigan

May is a pivotal month for Ogemaw County, Michigan gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 17
Avg. first frost October 3
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Transplant shiso outside

    Frost risk is low now in Ogemaw County, Michigan. If you've been covering beds overnight, you can stop.

  2. Scatter shiso into prepared beds

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

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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.

Ogemaw County, Michigan is in USDA Zone 5a. The average last spring frost is May 17 and the first fall frost is October 3, giving you a growing season of approximately 139 days.

At an elevation of 987 feet, Ogemaw County receives approximately 36.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Shiso to ensure they mature before fall.

Ogemaw County, MI (Zone 5a) Short season
139 days
Last Spring Frost May 17
139 growing days
First Fall Frost October 3

Ogemaw County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 22 Transplant: May 24 🍅 Harvest: Jul 19 – Sep 13
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Jul 26 – Sep 20
Safe Start (90%) ✓ Fits season (14 days to spare)
Start indoors: Apr 12 Transplant: Jun 14 🍅 Harvest: Aug 9 – Oct 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.

Soil Compatibility in Ogemaw County

How your county's soil matches Shiso's growing requirements.

Soil pH

Your soil pH (6.3–7.0) is within Shiso's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Ogemaw County is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Shiso.

How to Plant Shiso

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Shiso

3
successive plantings in your 139-day season

Sow every 5.7 weeks. Last sowing by Jul 25 to harvest before frost.

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
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Shiso

Shiso needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Shiso Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Ogemaw County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Shiso Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Shiso needs ~780 GDD — county provides 1,807 GDD Excellent fit

Shiso Planting Timeline — Ogemaw County, MI

Shiso Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 24 May 24 – Jun 14
Harvest July 26 Jul 26 – Sep 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

139 days in Ogemaw County

Growing Tips for Shiso in Ogemaw County

Direct sow Shiso outdoors after May 17 in Ogemaw County when soil has warmed and frost danger has passed.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Shiso in Ogemaw County, MI?

Ogemaw County is in Zone 5a with an average last frost of May 17. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ogemaw County, MI?

Ogemaw County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 17 and first fall frost is October 3.

🌱

Your Ogemaw County Garden Planner — Free

A 24-page printable planner built for Ogemaw County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Ogemaw County, MI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.