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When to Plant Shiso in Stevens County, MN

Stevens County, Minnesota Zone 4b May

Your May planting checklist for Stevens County, Minnesota

We've pulled the most time-sensitive tasks for Stevens County, Minnesota this May and put them front and centre. Tackle them in order.

Avg. last frost May 2
Avg. first frost October 6
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Move shiso into the garden

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

  2. Plant shiso from seed, right in the garden

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

Looking ahead to June
  • Starting indoors: shiso

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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.

Stevens County, Minnesota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 6, giving you a growing season of approximately 157 days.

At an elevation of 1,259 feet, Stevens County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Shiso to ensure they mature before fall.

Stevens County, MN (Zone 4b) Moderate season
157 days
Last Spring Frost May 2
157 growing days
First Fall Frost October 6
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Stevens County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 1 Transplant: May 17 🍅 Harvest: Jul 12 – Sep 6
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Mar 7 Transplant: May 23 🍅 Harvest: Jul 18 – Sep 12
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Mar 20 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.

Soil Compatibility in Stevens County

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

Soil pH

Your soil pH (6.1–7.0) is within Shiso's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Shiso will thrive.

How to Plant Shiso

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

Succession Planting Shiso

3
successive plantings in your 157-day season

Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Only during dry spells
Season total 4 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 1.6" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.1" 0" ❄️ Dormant
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Stevens 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 ~645 GDD — county provides 1,687 GDD Excellent fit

Shiso Planting Timeline — Stevens County, MN

Shiso Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 9 May 9 – May 30
Harvest July 18 Jul 18 – Sep 12

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

157 days in Stevens County

Growing Tips for Shiso in Stevens County

Direct sow Shiso outdoors after May 02 in Stevens 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 Stevens County, MN?

Stevens County is in Zone 4b with an average last frost of May 2. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stevens County, MN?

Stevens County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 6.

🌱

Your Stevens County Garden Planner — Free

A 24-page printable planner built for Stevens County (Zone 4b). 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 Stevens County, MN. 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.