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When to Plant Shiso in Throckmorton County, TX

Throckmorton County, Texas Zone 8a May

May to-do list for Throckmorton County, Texas

May is a pivotal month for Throckmorton County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 31
Avg. first frost November 9
Soil temp (4") 54°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
  1. Indoor seed-starting week for shiso

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

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.

Throckmorton County, Texas is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is November 9, giving you a growing season of approximately 223 days.

At an elevation of 4,952 feet, Throckmorton County receives approximately 60.7 inches of rainfall annually with predominantly loam soil. Summer highs average 89°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.

Throckmorton County, TX (Zone 8a) Long season
223 days
Last Spring Frost March 31
223 growing days
First Fall Frost November 9
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Throckmorton County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: May 30 – Jul 25
Recommended (50%) ✓ Fits season (97 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🍅 Harvest: Jun 9 – Aug 4
Safe Start (90%) ✓ Fits season (95 days to spare)
Start indoors: Feb 26 Transplant: Apr 30 🍅 Harvest: Jun 25 – Aug 20

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 Throckmorton County

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

Soil pH

Your soil pH (6.5–7.2) overlaps with Shiso's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Shiso.

How to Plant Shiso

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

Succession Planting Shiso

5
successive plantings in your 223-day season

Sow every 5.7 weeks. Last sowing by Aug 31 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/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 1.6" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 5.9" 0" ✅ Rainfall sufficient
May 4.3" 8.5" 0" ✅ Rainfall sufficient
Jun 4.3" 11.2" 0" ✅ Rainfall sufficient
Jul 4.3" 7.3" 0" ✅ Rainfall sufficient
Aug 4.3" 7.9" 0" ✅ Rainfall sufficient
Sep 4.3" 4.9" 0" ✅ Rainfall sufficient
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Throckmorton 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 ~1,005 GDD — county provides 3,735 GDD Excellent fit

Shiso Planting Timeline — Throckmorton County, TX

Shiso Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 7 Apr 7 – Apr 28
Harvest June 9 Jun 9 – Aug 4

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May
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 · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

223 days in Throckmorton County

Growing Tips for Shiso in Throckmorton County

Direct sow Shiso outdoors after March 31 in Throckmorton 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 Throckmorton County, TX?

Throckmorton County is in Zone 8a with an average last frost of March 31. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Throckmorton County, TX?

Throckmorton County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is November 9.

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Your Throckmorton County Garden Planner — Free

A 24-page printable planner built for Throckmorton County (Zone 8a). 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 Throckmorton 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.