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When to Plant Shiso in Gregg County, TX

Gregg County, Texas Zone 8b May

Your May gardening checklist

Your Gregg County, Texas garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 9
Avg. first frost November 17
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Start harvesting shiso

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

June prep starts now
  • 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.

Gregg County, Texas is in USDA Zone 8b. The average last spring frost is March 9 and the first fall frost is November 17, giving you a growing season of approximately 253 days.

At an elevation of 337 feet, Gregg County receives approximately 74.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°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.

Gregg County, TX (Zone 8b) Long season
253 days
Last Spring Frost March 9
253 growing days
First Fall Frost November 17

Gregg County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Jan 10 Transplant: Mar 14 🍅 Harvest: May 9 – Jul 4
Recommended (50%) ✓ Fits season (127 days to spare)
Start indoors: Jan 19 Transplant: Mar 23 🍅 Harvest: May 18 – Jul 13
Safe Start (90%) ✓ Fits season (121 days to spare)
Start indoors: Feb 8 Transplant: Apr 12 🍅 Harvest: Jun 7 – Aug 2

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 Gregg County

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

Soil pH

Your soil pH (5.5–6.3) is within Shiso's preferred range (5.5–7.0).

Soil Texture

Sandy soil in Gregg 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 (2.2%). 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 253-day season

Sow every 5.7 weeks. Last sowing by Sep 08 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 150 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 2.8" 0" ❄️ Dormant
Mar 4.3" 4.8" 0" ✅ Rainfall sufficient
Apr 4.3" 6.7" 0" ✅ Rainfall sufficient
May 4.3" 11.1" 0" ✅ Rainfall sufficient
Jun 4.3" 13" 0" ✅ Rainfall sufficient
Jul 4.3" 9.4" 0" ✅ Rainfall sufficient
Aug 4.3" 8.8" 0" ✅ Rainfall sufficient
Sep 4.3" 6.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.6" 0" ✅ Rainfall sufficient
Nov 4.3" 2.8" 1.5" 💧 Light watering
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Gregg 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 ~1,320 GDD — county provides 5,566 GDD Excellent fit

Shiso Planting Timeline — Gregg County, TX

Shiso Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 – Feb 2
Transplant Outdoors March 23 Mar 23 – Apr 6
Direct Sow March 16 Mar 16 – Apr 6
Harvest May 18 May 18 – Jul 13

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 Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August
September
October
November
December

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 8b

📆 Growing Season

253 days in Gregg County

Growing Tips for Shiso in Gregg County

Direct sow Shiso outdoors after March 09 in Gregg County when soil has warmed and frost danger has passed.

Sandy soil in Gregg 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 96°F in Gregg 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 Gregg County, TX?

Gregg County is in Zone 8b with an average last frost of March 9. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gregg County, TX?

Gregg County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 9 and first fall frost is November 17.

🌱

Your Gregg County Garden Planner — Free

A 24-page printable planner built for Gregg County (Zone 8b). 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 Gregg County, TX. 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.