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When to Plant Mitsuba in Delaware County, OK

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.

Delaware County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 25, giving you a growing season of approximately 199 days.

At an elevation of 440 feet, Delaware County receives approximately 30.3 inches of rainfall annually with predominantly loam soil. Summer highs average 94ยฐF, providing good warmth for Mitsuba during the growing season.

Delaware County, OK (Zone 7a) Moderate season
199 days
Last Spring Frost April 9
199 growing days
First Fall Frost October 25

Delaware County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Feb 27 Transplant: Mar 27 🍅 Harvest: May 22 – Jul 17
Recommended (50%) ✓ Fits season (94 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🍅 Harvest: May 28 – Jul 23
Safe Start (90%) ✓ Fits season (96 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 Delaware County

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

Soil pH

Your soil pH (6.3โ€“7.6) overlaps with Mitsuba's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Delaware County is excellent for Mitsuba โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). 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

4
successive plantings in your 199-day season

Sow every 5.7 weeks. Last sowing by Aug 16 to harvest before frost.

For a dedicated fall crop, sow by Aug 16.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 766 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 0.7" 0" โ„๏ธ Dormant
Feb โ€” 0.9" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
May 4.3" 4.8" 0" โœ… Rainfall sufficient
Jun 4.3" 4.3" 0" โœ… Rainfall sufficient
Jul 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Aug 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Sep 4.3" 3.1" 1.2" ๐Ÿ’ง Light watering
Oct 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Nov โ€” 0.9" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Delaware County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,230 GDD — county provides 4,079 GDD Excellent fit

Mitsuba Planting Timeline โ€” Delaware County, OK

Mitsuba Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 โ€“ Mar 19
Transplant Outdoors April 2 Apr 2 โ€“ Apr 16
Direct Sow March 26 Mar 26 โ€“ Apr 16
Harvest May 28 May 28 โ€“ Jul 23
Fall Sowing August 16 Aug 16 โ€“ Aug 30

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

199 days in Delaware County

Growing Tips for Mitsuba in Delaware County

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

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

What planting zone is Delaware County, OK?

Delaware County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 25.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Delaware County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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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 Delaware County, OK. Local conditions may vary. Last updated: April 2026.