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When to Plant Mitsuba in Ottawa County, OK

Ottawa County, Oklahoma Zone 7a May

May in the garden — Ottawa County, Oklahoma

May is a pivotal month for Ottawa County, Oklahoma gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 9
Avg. first frost October 26
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 14 hrs
  1. Indoor seed-starting week for mitsuba

    These need a head start before your last frost (April 9). Sow into cells now so you're ready to transplant in a few weeks.

  2. Pick mitsuba

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Coming up in June — start thinking about
  • 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.

Ottawa County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 26, giving you a growing season of approximately 200 days.

At an elevation of 716 feet, Ottawa County receives approximately 29.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Mitsuba during the growing season.

Ottawa County, OK (Zone 7a) Long season
200 days
Last Spring Frost April 9
200 growing days
First Fall Frost October 26
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Ottawa County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (94 days to spare)
Start indoors: Feb 27 Transplant: Mar 27 🍅 Harvest: May 22 – Jul 17
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🍅 Harvest: May 28 – Jul 23
Safe Start (90%) ✓ Fits season (95 days to spare)
Start indoors: Mar 19 Transplant: Apr 16 🍅 Harvest: Jun 11 – Aug 6

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 Ottawa County

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

Soil pH

Your soil pH (6.8–7.8) is more alkaline than Mitsuba prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 200-day season

Sow every 5.7 weeks. Last sowing by Aug 17 to harvest before frost.

For a dedicated fall crop, sow by Aug 17.

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 813 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.8" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ottawa 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 ~1,185 GDD — county provides 3,950 GDD Excellent fit

Mitsuba Planting Timeline — Ottawa County, OK

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 2 Apr 2 – Apr 16
Direct Sow March 26 Mar 26 – Apr 16
Harvest May 28 May 28 – Jul 23
Fall Sowing August 17 Aug 17 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August Fall Sowing
September
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: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

200 days in Ottawa County

Growing Tips for Mitsuba in Ottawa County

Direct sow Mitsuba outdoors after April 09 in Ottawa 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 Ottawa County, OK?

Ottawa County is in Zone 7a with an average last frost of April 9. Plan your Mitsuba planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ottawa County, OK?

Ottawa County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 26.

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Your Ottawa County Garden Planner — Free

A 24-page printable planner built for Ottawa County (Zone 7a). 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 Ottawa County, OK. 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.