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When to Plant Komatsuna in Dunn County, ND

Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.

Dunn County, North Dakota is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.

At an elevation of 944 feet, Dunn County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Komatsuna to ensure they mature before fall.

Dunn County, ND (Zone 4a) Short season
132 days
Last Spring Frost May 14
132 growing days
First Fall Frost September 23

Dunn County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (61 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jun 14 – Jul 19
Recommended (50%) ✓ Fits season (62 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jun 18 – Jul 23
Safe Start (90%) ✓ Fits season (62 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Jul 4 – Aug 8

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 Dunn County

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

Soil pH

Your soil pH (6.2โ€“7.5) is within Komatsuna's preferred range (6.0โ€“7.5).

Soil Texture

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

Drainage

Drainage is adequate for Komatsuna.

Organic Matter

Organic matter is excellent (4.2%) โ€” Komatsuna will thrive.

How to Plant Komatsuna

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Komatsuna

4
successive plantings in your 132-day season

Sow every 4 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Jul 01.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 832 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Komatsuna

Komatsuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Komatsuna Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 2.1" 0" โ„๏ธ Dormant
Apr โ€” 2.2" 0" โ„๏ธ Dormant
May 4.3" 2.5" 1.8" ๐Ÿ’ง Light watering
Jun 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Jul 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Aug 4.3" 2.6" 1.7" ๐Ÿ’ง Light watering
Sep 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Oct โ€” 2.1" 0" โ„๏ธ Dormant
Nov โ€” 1.5" 0" โ„๏ธ Dormant
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Dunn County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Komatsuna 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.

Komatsuna needs ~425 GDD — county provides 1,320 GDD Excellent fit

Komatsuna Planting Timeline โ€” Dunn County, ND

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors May 14 May 14 โ€“ May 28
Direct Sow May 7 May 7 โ€“ May 28
Harvest June 18 Jun 18 โ€“ Jul 23
Fall Sowing July 1 Jul 1 โ€“ Jul 15

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

35โ€“50 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

132 days in Dunn County

Growing Tips for Komatsuna in Dunn County

Direct sow Komatsuna outdoors after May 14 in Dunn County when soil has warmed and frost danger has passed.

Your generous 132.0-day season in Dunn County allows multiple plantings of Komatsuna. Sow every 17.0 days for continuous harvest.

Common pests for Komatsuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Dunn County receives only 22" of rain annually. Komatsuna needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow in spring or fall. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Komatsuna in Dunn County, ND?

Dunn County is in Zone 4a with an average last frost of May 14. Plan your Komatsuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Dunn County, ND?

Dunn County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 23.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Dunn County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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 Dunn County, ND. Local conditions may vary. Last updated: April 2026.