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When to Plant Shiso in Chisago County, MN

Chisago County, Minnesota Zone 4b May

What to do in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 3
Avg. first frost October 1
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Time to transplant shiso

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Put shiso seeds straight in the ground

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Before June arrives, get these ready
  • 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.

Chisago County, Minnesota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 1, giving you a growing season of approximately 151 days.

At an elevation of 1,324 feet, Chisago County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Shiso to ensure they mature before fall.

Chisago County, MN (Zone 4b) Moderate season
151 days
Last Spring Frost May 3
151 growing days
First Fall Frost October 1
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Chisago County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 3 Transplant: May 19 🍅 Harvest: Jul 14 – Sep 8
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Mar 8 Transplant: May 24 🍅 Harvest: Jul 19 – Sep 13
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Mar 24 Transplant: Jun 9 🍅 Harvest: Aug 4 – Sep 29

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 Chisago County

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

Soil pH

Your soil pH (6.0–6.8) is within Shiso's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 151-day season

Sow every 5.7 weeks. Last sowing by Jul 23 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Chisago 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 ~690 GDD — county provides 1,736 GDD Excellent fit

Shiso Planting Timeline — Chisago County, MN

Shiso Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 10 May 10 – May 31
Harvest July 19 Jul 19 – Sep 13

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 · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

151 days in Chisago County

Growing Tips for Shiso in Chisago County

Direct sow Shiso outdoors after May 03 in Chisago 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 Chisago County, MN?

Chisago County is in Zone 4b with an average last frost of May 3. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chisago County, MN?

Chisago County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 1.

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Your Chisago County Garden Planner — Free

A 24-page printable planner built for Chisago 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 Chisago 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.