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When to Plant Shiso in Morgan County, UT

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.

Morgan County, Utah is in USDA Zone 5b. The average last spring frost is June 17 and the first fall frost is August 31, giving you a growing season of approximately 75 days.

At an elevation of 6,439 feet, Morgan County receives approximately 14.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Shiso to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Shiso successfully. Mulch heavily to conserve soil moisture.

Morgan County, UT (Zone 5b) Very short season
75 days
Last Spring Frost June 17
75 growing days
First Fall Frost August 31

Morgan County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 22 Transplant: Jun 24 🍅 Harvest: Aug 19 – Oct 14
Recommended (50%) ✗ May not fit
Start indoors: Apr 29 Transplant: Jul 1 🍅 Harvest: Aug 26 – Oct 21
Safe Start (90%) ✗ May not fit
Start indoors: May 6 Transplant: Jul 8 🍅 Harvest: Sep 2 – Oct 28

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 Morgan County

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

Soil pH

Your soil pH (6.5โ€“8.1) is more alkaline than Shiso prefers (5.5โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Morgan County is excellent for Shiso โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Shiso.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Shiso.

How to Plant Shiso

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 395 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 1.1" 0" โ„๏ธ Dormant
Feb โ€” 0.8" 0" โ„๏ธ Dormant
Mar โ€” 1.2" 0" โ„๏ธ Dormant
Apr โ€” 1.4" 0" โ„๏ธ Dormant
May โ€” 1.8" 0" โ„๏ธ Dormant
Jun 4.3" 0.9" 3.4" ๐Ÿšฟ Regular watering
Jul 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Aug 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Sep โ€” 1.2" 0" โ„๏ธ Dormant
Oct โ€” 1.1" 0" โ„๏ธ Dormant
Nov โ€” 1" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Aug in Morgan County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~780 GDD — county provides 975 GDD Good fit

Shiso Planting Timeline โ€” Morgan County, UT

Shiso Planting Calendar

Activity When Date Range
Start Indoors April 29 Apr 29 โ€“ May 13
Transplant Outdoors July 1 Jul 1 โ€“ Jul 15
Direct Sow June 24 Jun 24 โ€“ Jul 15
Harvest August 26 Aug 26 โ€“ Oct 21

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

75 days in Morgan County

Growing Tips for Shiso in Morgan County

Direct sow Shiso outdoors after June 17 in Morgan County when soil has warmed and frost danger has passed.

Morgan County receives only 14" of rain annually. Shiso needs consistent moisture โ€” 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 Morgan County, UT?

Morgan County is in Zone 5b with an average last frost of June 17. Plan your Shiso planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Morgan County, UT?

Morgan County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is June 17 and first fall frost is August 31.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Morgan County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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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 Morgan County, UT. Local conditions may vary. Last updated: April 2026.