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When to Plant Mitsuba in Judith Basin County, MT

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.

Judith Basin County, Montana is in USDA Zone 4a. The average last spring frost is May 23 and the first fall frost is September 19, giving you a growing season of approximately 119 days.

At an elevation of 6,308 feet, Judith Basin County receives approximately 17.7 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Mitsuba to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Mitsuba successfully. Mulch heavily to conserve soil moisture.

Judith Basin County, MT (Zone 4a) Short season
119 days
Last Spring Frost May 23
119 growing days
First Fall Frost September 19

Judith Basin County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jul 4 – Aug 29
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Apr 11 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 5
Safe Start (90%) ✓ Fits season (11 days to spare)
Start indoors: Apr 28 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 22

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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 477 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Mitsuba needs ~600 GDD — county provides 1,190 GDD Excellent fit

Mitsuba Planting Timeline โ€” Judith Basin County, MT

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors April 11 Apr 11 โ€“ Apr 25
Transplant Outdoors May 16 May 16 โ€“ May 30
Direct Sow May 16 May 16 โ€“ Jun 6
Fall Sowing June 27 Jun 27 โ€“ Jul 11
Harvest July 11 Jul 11 โ€“ Sep 5

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 Transplant Outdoors Direct Sow
June Direct Sow Fall Sowing
July Fall Sowing Harvest
August 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 4a

Growing Season

119 days

Growing Tips for Judith Basin 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 Judith Basin County, MT?

Judith Basin County is in Zone 4a with an average last frost of May 23. Plan your Mitsuba planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Judith Basin County, MT?

Judith Basin County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 23 and first fall frost is September 19.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Judith Basin County gardeners in Zone 4a 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 Judith Basin County, MT. Local conditions may vary. Last updated: April 2026.