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When to Plant Shiso in Campbell County, SD

Campbell County, South Dakota Zone 4b May

May in the garden — Campbell County, South Dakota

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

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 49°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Outdoor sowing time: shiso

    Your soil is 49°F — warm enough for these to germinate without babying.

June will be here before you know it — start on
  • Transplants going out: 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.

Campbell County, South Dakota is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 830 feet, Campbell County receives approximately 27.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Shiso to ensure they mature before fall.

Campbell County, SD (Zone 4b) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30
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Campbell County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Mar 7 Transplant: May 23 🍅 Harvest: Jul 18 – Sep 12
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Mar 16 Transplant: Jun 1 🍅 Harvest: Jul 27 – Sep 21
Safe Start (90%) ✓ Fits season (11 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 Campbell County

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

Soil pH

Your soil pH (6.5–7.5) overlaps with Shiso's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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 142-day season

Sow every 5.7 weeks. Last sowing by Jul 22 to harvest before frost.

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 251 gal / 100 sq ft

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 1.9" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 2.1" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Campbell 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 ~600 GDD — county provides 1,420 GDD Excellent fit

Shiso Planting Timeline — Campbell County, SD

Shiso Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors June 1 Jun 1 – Jun 15
Direct Sow May 18 May 18 – Jun 8
Harvest July 27 Jul 27 – Sep 21

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Direct Sow
June Transplant Outdoors Direct Sow
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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

142 days in Campbell County

Growing Tips for Shiso in Campbell County

Direct sow Shiso outdoors after May 11 in Campbell 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 Campbell County, SD?

Campbell County is in Zone 4b with an average last frost of May 11. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Campbell County, SD?

Campbell County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is September 30.

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Your Campbell County Garden Planner — Free

A 24-page printable planner built for Campbell 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 Campbell County, SD. 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.