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When to Plant Shiso in Tooele County, UT

Tooele County, Utah Zone 6b May

Your May planting checklist for Tooele County, Utah

Each item below is timed to Tooele County, Utah's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 1
Avg. first frost October 17
Soil temp (4") 52°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Move shiso into the garden

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Sow shiso where they'll grow

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

To set up a strong June, finish these tasks
  • Starting indoors: 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.

Tooele County, Utah is in USDA Zone 6b. The average last spring frost is May 1 and the first fall frost is October 17, giving you a growing season of approximately 169 days.

At an elevation of 4,309 feet, Tooele County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Shiso during the growing season. With low rainfall, drip irrigation is essential for growing Shiso successfully. Mulch heavily to conserve soil moisture.

Tooele County, UT (Zone 6b) Moderate season
169 days
Last Spring Frost May 1
169 growing days
First Fall Frost October 17
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Tooele County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Mar 7 Transplant: May 9 🍅 Harvest: Jul 4 – Aug 29
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Mar 13 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 4
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Mar 30 Transplant: Jun 1 🍅 Harvest: Jul 27 – Sep 21

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 Tooele County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Shiso prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Shiso.

How to Plant Shiso

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

Succession Planting Shiso

3
successive plantings in your 169-day season

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,240 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 0.8" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1" 3.3" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Tooele 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 2,830 GDD Excellent fit

Shiso Planting Timeline — Tooele County, UT

Shiso Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest July 10 Jul 10 – Sep 4

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

169 days in Tooele County

Growing Tips for Shiso in Tooele County

Direct sow Shiso outdoors after May 01 in Tooele County when soil has warmed and frost danger has passed.

Tooele County receives only 13" of rain annually. Shiso needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Tooele County, UT?

Tooele County is in Zone 6b with an average last frost of May 1. Plan your Shiso planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tooele County, UT?

Tooele County, Utah is in USDA Hardiness Zone 6b. The average last spring frost is May 1 and first fall frost is October 17.

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Your Tooele County Garden Planner — Free

A 24-page printable planner built for Tooele County (Zone 6b). 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 Tooele County, UT. 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.