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When to plant Mitsuba in Greene County, IA

In Zone 5a (Greene County), direct-sow Mitsuba between April 13 and May 4 for spring, after the April 27 last-frost mark. A second sowing from July 27 to August 10 extends the harvest into fall.

When to Plant Mitsuba in Greene County, IA

Greene County, Iowa Zone 5a August

Greene County, Iowa gardeners: here's your August plan

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

Avg. last frost April 27
Avg. first frost October 5
Soil temp (4") 77°F
Watering Moderate
Pest pressure High
Daylight 13.7 hrs
  1. Collect mitsuba at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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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.

Greene County, Iowa is in USDA Zone 5a. The average last spring frost is April 27 and the first fall frost is October 5, giving you a growing season of approximately 161 days.

At an elevation of 1,292 feet, Greene County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Mitsuba during the growing season.

Greene County, IA (Zone 5a) Moderate season
161 days
Last Spring Frost April 27
161 growing days
First Fall Frost October 5

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Mitsuba Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Mar 18 Transplant: Apr 15 🍅 Harvest: Jun 10 – Aug 5
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Mar 23 Transplant: Apr 20 🍅 Harvest: Jun 15 – Aug 10
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Apr 6 Transplant: May 4 🍅 Harvest: Jun 29 – Aug 24

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 Greene County

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

Soil pH

Your soil pH (5.8–6.9) overlaps with Mitsuba's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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

3
successive plantings in your 161-day season

Sow every 5.7 weeks. Last sowing by Jul 27 to harvest before frost.

For a dedicated fall crop, sow by Jul 27.

Mitsuba Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 173 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 1.4" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 3.3" 1" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Greene 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 2,334 GDD Excellent fit

Mitsuba Planting Timeline — Greene County, IA

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 13 Apr 13 – May 4
Harvest June 15 Jun 15 – Aug 10
Fall Sowing July 27 Jul 27 – Aug 10

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

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 5a

📆 Growing Season

161 days in Greene County

Growing Tips for Mitsuba in Greene County

Direct sow Mitsuba outdoors after April 27 in Greene 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 Greene County, IA?

Greene County is in Zone 5a with an average last frost of April 27. Plan your Mitsuba planting based on this frost date — see the calendar above for exact timing.

What planting zone is Greene County, IA?

Greene County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 27 and first fall frost is October 5.

When should I plant Mitsuba in Greene County, IA?

In Greene County, IA, plant Mitsuba after the last frost (around April 27) and before the first frost (around October 5). Best results when soil holds above 50°F.

What growing zone is Greene County, IA for Mitsuba?

Greene County sits in USDA Zone 5a. Mitsuba grows reliably in zones 4a through 9b, so it's a good fit here.

Can Mitsuba grow in Greene County's climate?

Yes — Mitsuba grows well in Greene County's temperate climate. Greene County averages a 161-day frost-free season, with last frost around April 27 and first frost around October 5.

🌱

Your Greene County Garden Planner — Free

A 22-page printable planner built for Greene 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.

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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 Greene County, IA. Local conditions may vary. Last updated: August 2026.

Sources & credits

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