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When to Plant Shiso in Bullitt County, KY

Bullitt County, Kentucky Zone 7a May

Bullitt County, Kentucky gardeners: here's your May plan

A quick May briefing for Bullitt County, Kentucky gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 7
Avg. first frost October 30
Soil temp (4") 58°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Fire up the seed-starting tray: shiso

    Label every cell. You will absolutely forget which is which otherwise.

A few tasks this May that'll pay off in June
  • First harvests: 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.

Bullitt County, Kentucky is in USDA Zone 7a. The average last spring frost is April 7 and the first fall frost is October 30, giving you a growing season of approximately 206 days.

At an elevation of 2,437 feet, Bullitt County receives approximately 46.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Shiso during the growing season.

Bullitt County, KY (Zone 7a) Long season
206 days
Last Spring Frost April 7
206 growing days
First Fall Frost October 30
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Bullitt County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (82 days to spare)
Start indoors: Feb 8 Transplant: Apr 12 🍅 Harvest: Jun 7 – Aug 2
Recommended (50%) ✓ Fits season (80 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 16 – Aug 11
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Mar 6 Transplant: May 8 🍅 Harvest: Jul 3 – Aug 28

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 Bullitt County

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

Soil pH

Your soil pH (5.8–6.7) is within Shiso's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Shiso.

How to Plant Shiso

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

Succession Planting Shiso

4
successive plantings in your 206-day season

Sow every 5.7 weeks. Last sowing by Aug 21 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 84 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 4.4" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 3.5" 0" ❄️ Dormant
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Bullitt 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 ~960 GDD — county provides 3,296 GDD Excellent fit

Shiso Planting Timeline — Bullitt County, KY

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 14 Apr 14 – May 5
Harvest June 16 Jun 16 – Aug 11

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September
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 7a

📆 Growing Season

206 days in Bullitt County

Growing Tips for Shiso in Bullitt County

Direct sow Shiso outdoors after April 07 in Bullitt 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 Bullitt County, KY?

Bullitt County is in Zone 7a with an average last frost of April 7. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bullitt County, KY?

Bullitt County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is April 7 and first fall frost is October 30.

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Your Bullitt County Garden Planner — Free

A 24-page printable planner built for Bullitt County (Zone 7a). 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 Bullitt County, KY. 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.