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When to Plant Shiso in Johnston County, OK

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.

Johnston County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 25 and the first fall frost is November 11, giving you a growing season of approximately 231 days.

At an elevation of 700 feet, Johnston County receives approximately 32.9 inches of rainfall annually with predominantly loam soil. Summer highs average 92ยฐF, providing good warmth for Shiso during the growing season.

Johnston County, OK (Zone 7b) Long season
231 days
Last Spring Frost March 25
231 growing days
First Fall Frost November 11

Johnston County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Start indoors: Jan 23 Transplant: Mar 27 🍅 Harvest: May 22 – Jul 17
Recommended (50%) ✓ Fits season (105 days to spare)
Start indoors: Feb 4 Transplant: Apr 8 🍅 Harvest: Jun 3 – Jul 29
Safe Start (90%) ✓ Fits season (102 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 19

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 Johnston County

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

Soil pH

Your soil pH (6.3โ€“7.3) overlaps with Shiso's range (5.5โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Johnston County is excellent for Shiso โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.2%) โ€” Shiso will thrive.

How to Plant Shiso

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

Succession Planting Shiso

5
successive plantings in your 231-day season

Sow every 5.7 weeks. Last sowing by Sep 02 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 826 gal / 100 sq ft
Shiso needs ~1,140 GDD — county provides 4,389 GDD Excellent fit

Shiso Planting Timeline โ€” Johnston County, OK

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 โ€“ Feb 18
Transplant Outdoors April 8 Apr 8 โ€“ Apr 22
Direct Sow April 1 Apr 1 โ€“ Apr 22
Harvest June 3 Jun 3 โ€“ Jul 29

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

231 days in Johnston County

Growing Tips for Shiso in Johnston County

Direct sow Shiso outdoors after March 25 in Johnston 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Shiso in Johnston County, OK?

Johnston County is in Zone 7b with an average last frost of March 25. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Johnston County, OK?

Johnston County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 25 and first fall frost is November 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Johnston County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Johnston County, OK. Local conditions may vary. Last updated: April 2026.