Blog

When to Plant Shiso in Webster Parish, LA

Webster Parish, Louisiana Zone 8b May

What to do in May

Each item below is timed to Webster Parish, Louisiana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 21
Avg. first frost November 10
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Get shiso seeds going inside

    You're about 26 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Collect shiso at their peak

    If you can't use it all right away, check the food-preservation section of your planner.

Before June arrives, get these ready
  • First harvests: shiso

Instant PDF download. No spam, unsubscribe any time.

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.

Webster Parish, Louisiana is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 10, giving you a growing season of approximately 234 days.

At an elevation of 138 feet, Webster Parish receives approximately 57 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Shiso during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shiso root diseases.

Webster Parish, LA (Zone 8b) Long season
234 days
Last Spring Frost March 21
234 growing days
First Fall Frost November 10
Share this guide:

Webster Parish Soil Profile

Soil Type

Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Start indoors: Jan 21 Transplant: Mar 25 🍅 Harvest: May 20 – Jul 15
Recommended (50%) ✓ Fits season (108 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: May 30 – Jul 25
Safe Start (90%) ✓ Fits season (102 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Aug 16

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 Webster Parish

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 loam soil in Webster Parish is excellent for Shiso — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Shiso.

How to Plant Shiso

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

Succession Planting Shiso

5
successive plantings in your 234-day season

Sow every 5.7 weeks. Last sowing by Sep 01 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

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 4.5" 0" ❄️ Dormant
Feb 5.1" 0" ❄️ Dormant
Mar 4.3" 5.5" 0" ✅ Rainfall sufficient
Apr 4.3" 4.6" 0" ✅ Rainfall sufficient
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 5.8" 0" ✅ Rainfall sufficient
Jul 4.3" 5.9" 0" ✅ Rainfall sufficient
Aug 4.3" 5" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 4.3" 4.4" 0" ✅ Rainfall sufficient
Dec 4.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Webster Parish). 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 ~1,230 GDD — county provides 4,797 GDD Excellent fit

Shiso Planting Timeline — Webster Parish, LA

Shiso Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 4 Apr 4 – Apr 18
Direct Sow March 28 Mar 28 – Apr 18
Harvest May 30 May 30 – Jul 25

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August
September
October
November
December
Share this guide:

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 8b

📆 Growing Season

234 days in Webster Parish

Growing Tips for Shiso in Webster Parish

Direct sow Shiso outdoors after March 21 in Webster Parish 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 Webster Parish, LA?

Webster Parish is in Zone 8b with an average last frost of March 21. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Webster Parish, LA?

Webster Parish, Louisiana is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 10.

🌱

Your Webster Parish Garden Planner — Free

A 24-page printable planner built for Webster Parish (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Webster Parish, LA. 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.