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When to Plant Mitsuba in Jefferson County, OH

Jefferson County, Ohio Zone 6b May

Your May planting checklist for Jefferson County, Ohio

Your garden in Jefferson County, Ohio is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 23
Avg. first frost October 29
Soil temp (4") 62°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Indoor seed-starting week for mitsuba

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Before June arrives, get these ready
  • First harvests: 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.

Jefferson County, Ohio is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 29, giving you a growing season of approximately 189 days.

At an elevation of 1,017 feet, Jefferson County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Mitsuba during the growing season.

Jefferson County, OH (Zone 6b) Moderate season
189 days
Last Spring Frost April 23
189 growing days
First Fall Frost October 29
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Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (83 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🍅 Harvest: Jun 2 – Jul 28
Recommended (50%) ✓ Fits season (84 days to spare)
Start indoors: Mar 19 Transplant: Apr 16 🍅 Harvest: Jun 11 – Aug 6
Safe Start (90%) ✓ Fits season (79 days to spare)
Start indoors: Apr 4 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 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.

Soil Compatibility in Jefferson County

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

Soil pH

Your soil pH (5.9–7.1) overlaps with Mitsuba's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Jefferson 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 (4.9%) — Mitsuba will thrive.

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

4
successive plantings in your 189-day season

Sow every 5.7 weeks. Last sowing by Aug 20 to harvest before frost.

For a dedicated fall crop, sow by Aug 20.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 695 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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jefferson 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 ~870 GDD — county provides 2,740 GDD Excellent fit

Mitsuba Planting Timeline — Jefferson County, OH

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 9 Apr 9 – Apr 30
Harvest June 11 Jun 11 – Aug 6
Fall Sowing August 20 Aug 20 – Sep 3

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

189 days in Jefferson County

Growing Tips for Mitsuba in Jefferson County

Direct sow Mitsuba outdoors after April 23 in Jefferson 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 Jefferson County, OH?

Jefferson County is in Zone 6b with an average last frost of April 23. Plan your Mitsuba planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, OH?

Jefferson County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 29.

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Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 6b). 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 Jefferson County, OH. 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.