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When to Plant Mitsuba in Box Elder County, UT

Mitsuba (Japanese parsley) is a shade-loving herb with trefoil leaves and a mild celery-parsley flavor. It is essential in Japanese cuisine for soups, salads, and garnishes.

Box Elder County, Utah is in USDA Zone 6a. The average last spring frost is May 22 and the first fall frost is October 3, giving you a growing season of approximately 134 days.

At an elevation of 4,039 feet, Box Elder County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Mitsuba during the growing season.

Box Elder County, UT (Zone 6a) Short season
134 days
Last Spring Frost May 22
134 growing days
First Fall Frost October 3

Box Elder County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Apr 7 Transplant: May 5 🍅 Harvest: Jun 30 – Aug 25
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Apr 17 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 4
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: May 6 Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 23

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 332 gal / 100 sq ft
Drought risk

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

Mitsuba needs ~915 GDD — county provides 2,043 GDD Excellent fit

Mitsuba Planting Timeline โ€” Box Elder County, UT

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 โ€“ May 1
Transplant Outdoors May 15 May 15 โ€“ May 29
Direct Sow May 8 May 8 โ€“ May 29
Fall Sowing July 25 Jul 25 โ€“ Aug 8
Harvest July 10 Jul 10 โ€“ Sep 4

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 Transplant Outdoors Direct Sow
June โ€”
July Fall Sowing Harvest
August Fall Sowing Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“70 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

134 days

Growing Tips for Box Elder County

Direct sow or start indoors in partial shade. Mitsuba prefers cool, moist conditions. Harvest outer stems as needed. Self-sows readily in shaded garden areas.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Mitsuba in Box Elder County, UT?

Box Elder County is in Zone 6a with an average last frost of May 22. Plan your Mitsuba planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Box Elder County, UT?

Box Elder County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 22 and first fall frost is October 3.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Box Elder County gardeners in Zone 6a 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 Box Elder County, UT. Local conditions may vary. Last updated: April 2026.