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When to Plant Shiso in Pearl River County, MS

Pearl River County, Mississippi Zone 9a May

May to-do list for Pearl River County, Mississippi

Here's what deserves your attention in Pearl River County, Mississippi this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost March 3
Avg. first frost November 24
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: shiso

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

Looking ahead to 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.

Pearl River County, Mississippi is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 24, giving you a growing season of approximately 266 days.

At an elevation of 243 feet, Pearl River County receives approximately 56.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Shiso may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Shiso will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Shiso root diseases.

Pearl River County, MS (Zone 9a) Long season
266 days
Last Spring Frost March 3
266 growing days
First Fall Frost November 24
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Pearl River County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (153 days to spare)
Start indoors: Jan 6 Transplant: Feb 24 🍅 Harvest: Apr 21 – Jun 16
Recommended (50%) ✓ Fits season (147 days to spare)
Start indoors: Jan 20 Transplant: Mar 10 🍅 Harvest: May 5 – Jun 30
Safe Start (90%) ✓ Fits season (145 days to spare)
Start indoors: Feb 12 Transplant: Apr 2 🍅 Harvest: May 28 – Jul 23

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 Pearl River County

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

Soil pH

Your soil pH (4.8–6.0) is more acidic than Shiso prefers (5.5–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Pearl River County warms quickly in spring but drains fast. Shiso will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Shiso.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Shiso.

How to Plant Shiso

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

Succession Planting Shiso

6
successive plantings in your 266-day season

Sow every 5.7 weeks. Last sowing by Sep 15 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/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 4.2" 0" ❄️ Dormant
Feb 4.8" 0" ❄️ Dormant
Mar 4.3" 5.1" 0" ✅ Rainfall sufficient
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.6" 0" ✅ Rainfall sufficient
Jul 4.3" 5.5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 4.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 4.6" 0" ✅ Rainfall sufficient
Dec 4.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Pearl River 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 ~1,365 GDD — county provides 6,051 GDD Excellent fit

Shiso Planting Timeline — Pearl River County, MS

Shiso Planting Calendar

Activity When Date Range
Start Indoors January 20 Jan 20 – Feb 3
Transplant Outdoors March 10 Mar 10 – Mar 24
Direct Sow March 10 Mar 10 – Mar 31
Harvest May 5 May 5 – Jun 30

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9a

📆 Growing Season

266 days in Pearl River County

Growing Tips for Shiso in Pearl River County

Direct sow Shiso outdoors after March 03 in Pearl River County when soil has warmed and frost danger has passed.

Sandy soil in Pearl River County dries quickly — mulch Shiso with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Pearl River County, provide afternoon shade for Shiso and water deeply in the morning.

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 Pearl River County, MS?

Pearl River County is in Zone 9a with an average last frost of March 3. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pearl River County, MS?

Pearl River County, Mississippi is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 24.

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Your Pearl River County Garden Planner — Free

A 24-page printable planner built for Pearl River County (Zone 9a). 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 Pearl River County, MS. 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.