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When to Plant Komatsuna in Cache 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.

Cache County, Utah is in USDA Zone 5b. The average last spring frost is June 11 and the first fall frost is September 2, giving you a growing season of approximately 83 days.

At an elevation of 6,265 feet, Cache County receives approximately 15.5 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. With low rainfall, drip irrigation is essential for growing Komatsuna successfully. Mulch heavily to conserve soil moisture.

Cache County, UT (Zone 5b) Very short season
83 days
Last Spring Frost June 11
83 growing days
First Fall Frost September 2

Cache County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jun 19 – Jul 24
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: May 7 Transplant: Jun 11 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (47 days to spare)
Start indoors: May 20 Transplant: Jun 24 🍅 Harvest: Jul 29 – Sep 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 191 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

Komatsuna needs ~552 GDD — county provides 1,079 GDD Excellent fit

Komatsuna Planting Timeline โ€” Cache County, UT

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors May 7 May 7 โ€“ May 21
Transplant Outdoors June 11 Jun 11 โ€“ Jun 25
Direct Sow May 28 May 28 โ€“ Jun 18
Fall Sowing June 24 Jun 24 โ€“ Jul 8
Harvest July 16 Jul 16 โ€“ Aug 20

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

35โ€“50 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

83 days

Growing Tips for Cache 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Komatsuna in Cache County, UT?

Cache County is in Zone 5b with an average last frost of June 11. Plan your Komatsuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cache County, UT?

Cache County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is June 11 and first fall frost is September 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cache 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 Cache County, UT. Local conditions may vary. Last updated: April 2026.