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When to Plant Shiso in Orange County, TX

Orange County, Texas Zone 9b May

Your May planting checklist for Orange County, Texas

Your Orange 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 February 12
Avg. first frost December 11
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Bring in the shiso

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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.

Orange County, Texas is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 11, giving you a growing season of approximately 302 days.

At an elevation of 231 feet, Orange County receives approximately 63.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°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.

Orange County, TX (Zone 9b) Year-round
302 days
Last Spring Frost February 12
302 growing days
First Fall Frost December 11

Orange County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.8-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (196 days to spare)
Start indoors: Dec 10 Transplant: Jan 28 🍅 Harvest: Mar 25 – May 20
Recommended (50%) ✓ Fits season (183 days to spare)
Start indoors: Jan 1 Transplant: Feb 19 🍅 Harvest: Apr 16 – Jun 11
Safe Start (90%) ✓ Fits season (176 days to spare)
Start indoors: Jan 22 Transplant: Mar 12 🍅 Harvest: May 7 – Jul 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 Orange County

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

Soil pH

Your soil pH (5.8–6.5) is within Shiso's preferred range (5.5–7.0).

Soil Texture

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

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

7
successive plantings in your 302-day season

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 392 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.8" 0" ❄️ Dormant
Feb 4.3" 2.1" 2.2" 🚿 Regular watering
Mar 4.3" 4.2" 0.1" 💧 Light watering
Apr 4.3" 6.3" 0" ✅ Rainfall sufficient
May 4.3" 8.3" 0" ✅ Rainfall sufficient
Jun 4.3" 11.1" 0" ✅ Rainfall sufficient
Jul 4.3" 7.6" 0" ✅ Rainfall sufficient
Aug 4.3" 7.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.4" 0" ✅ Rainfall sufficient
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 4.3" 2.1" 2.2" 🚿 Regular watering
Dec 4.3" 1.6" 2.7" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Orange 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 ~1,410 GDD — county provides 7,120 GDD Excellent fit

Shiso Planting Timeline — Orange County, TX

Shiso Planting Calendar

Activity When Date Range
Start Indoors January 1 Jan 1 – Jan 15
Transplant Outdoors February 19 Feb 19 – Mar 5
Direct Sow February 19 Feb 19 – Mar 12
Harvest April 16 Apr 16 – Jun 11

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April Harvest
May Harvest
June Harvest
July
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 9b

📆 Growing Season

302 days in Orange County

Growing Tips for Shiso in Orange County

Direct sow Shiso outdoors after February 12 in Orange County when soil has warmed and frost danger has passed.

Sandy soil in Orange 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 98°F in Orange 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 Orange County, TX?

Orange County is in Zone 9b with an average last frost of February 12. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Orange County, TX?

Orange County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 12 and first fall frost is December 11.

🌱

Your Orange County Garden Planner — Free

A 24-page printable planner built for Orange County (Zone 9b). 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 Orange 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.