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When to plant Mitsuba in Mahnomen County County,

For Mahnomen County County, gardeners: plant Mitsuba May 6 through May 27 once soil reads 50°F. A second sowing from July 5 to July 19 extends the harvest into fall.

When to Plant Mitsuba in Mahnomen County, MN

Mahnomen County, Minnesota Zone 4a June

What to do in June

Your Mahnomen County, Minnesota garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 13
Avg. first frost September 27
Soil temp (4") 60°F
Watering Low
Pest pressure Moderate
Daylight 15.7 hrs
  1. Start mitsuba indoors

    These need a head start before your last frost (May 13). Sow into cells now so you're ready to transplant in a few weeks.

Before July arrives, get these ready
  • First harvests: mitsuba
  • Fall sowing: mitsuba

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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.

Mahnomen County, Minnesota is in USDA Zone 4a. The average last spring frost is May 13 and the first fall frost is September 27, giving you a growing season of approximately 137 days.

At an elevation of 1,223 feet, Mahnomen County receives approximately 33.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Mitsuba to ensure they mature before fall.

Mahnomen County, MN (Zone 4a) Short season
137 days
Last Spring Frost May 13
137 growing days
First Fall Frost September 27
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Mahnomen County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Mitsuba Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 25 – Aug 20
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jul 1 – Aug 26
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: Apr 11 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 5

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 Mahnomen County

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

Soil pH

Your soil pH (5.9–7.0) overlaps with Mitsuba's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Mahnomen County is excellent for Mitsuba — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Mitsuba.

Organic Matter

Organic matter is excellent (4.0%) — Mitsuba will thrive.

How to Plant Mitsuba

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Mitsuba

3
successive plantings in your 137-day season

Sow every 5.7 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Jul 05.

Mitsuba Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 348 gal / 100 sq ft

Monthly Watering Guide for Mitsuba

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

Month Mitsuba Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 3.8" 0.5" 💧 Light watering
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 2.4" 0" ❄️ Dormant
Nov 2.4" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Mahnomen County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mitsuba 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" — every day above 50°F 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.

Mitsuba needs ~600 GDD — county provides 1,370 GDD Excellent fit

Mitsuba Planting Timeline — Mahnomen County, MN

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors May 6 May 6 – May 20
Direct Sow May 6 May 6 – May 27
Harvest July 1 Jul 1 – Aug 26
Fall Sowing July 5 Jul 5 – Jul 19

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

137 days in Mahnomen County

Growing Tips for Mitsuba in Mahnomen County

Direct sow Mitsuba outdoors after May 13 in Mahnomen County when soil has warmed and frost danger has passed.

Common pests for Mitsuba in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mitsuba in Mahnomen County, MN?

Mahnomen County is in Zone 4a with an average last frost of May 13. Plan your Mitsuba planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mahnomen County, MN?

Mahnomen County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 13 and first fall frost is September 27.

When should I plant Mitsuba in Mahnomen County, ?

In Mahnomen County, , plant Mitsuba after the last frost (around May 13) and before the first frost (around September 27). Best results when soil holds above 50°F.

What growing zone is Mahnomen County, for Mitsuba?

Mahnomen County sits in USDA Zone 4a. Mitsuba grows reliably in zones 4a through 9b, so it's a good fit here.

Can Mitsuba grow in Mahnomen County's climate?

Yes — Mitsuba grows well in Mahnomen County's temperate climate. Mahnomen County averages a 137-day frost-free season, with last frost around May 13 and first frost around September 27.

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Your Mahnomen County Garden Planner — Free

A 22-page printable planner built for Mahnomen County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Mahnomen County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.