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When to Plant Mitsuba in Somerset County, ME

Somerset County, Maine Zone 5a May

Your May planting checklist for Somerset County, Maine

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 22
Avg. first frost September 26
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Move mitsuba from tray to bed

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Direct-sow mitsuba

    Your soil is 54°F — warm enough for these to germinate without babying.

A few tasks this May that'll pay off in June
  • Starting indoors: 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.

Somerset County, Maine is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 26, giving you a growing season of approximately 127 days.

At an elevation of 356 feet, Somerset County receives approximately 48.8 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.

Somerset County, ME (Zone 5a) Short season
127 days
Last Spring Frost May 22
127 growing days
First Fall Frost September 26

Somerset County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Apr 10 Transplant: May 8 🍅 Harvest: Jul 3 – Aug 28
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Apr 17 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 4
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Apr 29 Transplant: May 27 🍅 Harvest: Jul 22 – Sep 16

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 Somerset County

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

Soil pH

Your soil pH (4.8–6.4) is more acidic than Mitsuba prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Mitsuba.

Organic Matter

Organic matter is moderate (3.3%). Annual compost additions will help Mitsuba.

How to Plant Mitsuba

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Mitsuba

2
successive plantings in your 127-day season

Sow every 5.7 weeks. Last sowing by Jul 18 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 2.9" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.6" 0" ❄️ Dormant
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.2" 0" ❄️ Dormant
Nov 3.8" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Somerset 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 1,270 GDD Excellent fit

Mitsuba Planting Timeline — Somerset County, ME

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 – May 1
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest July 10 Jul 10 – Sep 4
Fall Sowing July 18 Jul 18 – Aug 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

127 days in Somerset County

Growing Tips for Mitsuba in Somerset County

Direct sow Mitsuba outdoors after May 22 in Somerset 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 Somerset County, ME?

Somerset County is in Zone 5a with an average last frost of May 22. Plan your Mitsuba planting based on this frost date — see the calendar above for exact timing.

What planting zone is Somerset County, ME?

Somerset County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 26.

🌱

Your Somerset County Garden Planner — Free

A 24-page printable planner built for Somerset County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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