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When to Plant Komatsuna in Garfield County, UT

Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.

Garfield County, Utah is in USDA Zone 5b. The average last spring frost is May 27 and the first fall frost is September 21, giving you a growing season of approximately 117 days.

At an elevation of 5,058 feet, Garfield County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Komatsuna to ensure they mature before fall.

Garfield County, UT (Zone 5b) Short season
117 days
Last Spring Frost May 27
117 growing days
First Fall Frost September 21

Garfield County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Monthly Watering Guide for Komatsuna

Komatsuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Komatsuna Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.3" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 2.1" 0" โ„๏ธ Dormant
May 4.3" 2.3" 2" ๐Ÿ’ง Light watering
Jun 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Jul 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Aug 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Sep 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Oct โ€” 2" 0" โ„๏ธ Dormant
Nov โ€” 1.5" 0" โ„๏ธ Dormant
Dec โ€” 1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Garfield County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Komatsuna Planting Timeline โ€” Garfield County, UT

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors April 22 Apr 22 โ€“ May 6
Transplant Outdoors May 27 May 27 โ€“ Jun 10
Direct Sow May 13 May 13 โ€“ Jun 3
Harvest July 1 Jul 1 โ€“ Aug 5
Fall Sowing July 13 Jul 13 โ€“ Jul 27

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

Moderate โ€” regular watering

๐Ÿ“… Days to Maturity

35โ€“50 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

117 days in Garfield County

Growing Tips for Garfield County

Direct sow in spring or fall. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Komatsuna in Garfield County, UT?

Garfield County is in Zone 5b with an average last frost of May 27. Plan your Komatsuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Garfield County, UT?

Garfield County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is May 27 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Garfield County, UT. Local conditions may vary. Last updated: April 2026.