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When to Plant Napa Cabbage in Bowman County, ND

Bowman County, North Dakota Zone 4b May

Your May game plan for Bowman County, North Dakota

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 15
Avg. first frost September 24
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Plant out napa cabbage

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Sow napa cabbage where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

To set up a strong June, finish these tasks
  • Starting indoors: napa cabbage

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Napa cabbage forms tall, barrel-shaped heads with tender, crinkled leaves and a mild, slightly sweet flavor. It is the primary cabbage used for kimchi.

Bowman County, North Dakota is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 24, giving you a growing season of approximately 132 days.

At an elevation of 753 feet, Bowman County receives approximately 25.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Bowman County, ND (Zone 4b) Short season
132 days
Last Spring Frost May 15
132 growing days
First Fall Frost September 24

Bowman County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jul 7 – Aug 11
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Jul 10 – Aug 14
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Apr 21 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 1

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 Bowman County

How your county's soil matches Napa Cabbage's growing requirements.

Soil pH

Your soil pH (6.7–7.8) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Bowman County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Napa Cabbage is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (4.2%) — Napa Cabbage will thrive.

How to Plant Napa Cabbage

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Napa Cabbage

2
successive plantings in your 132-day season

Sow every 6.3 weeks. Last sowing by Jul 11 to harvest before frost.

For a dedicated fall crop, sow by Jul 02.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 1,592 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Napa Cabbage

Napa Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Napa Cabbage Needs Rainfall You Supplement Action
Jan 2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 6.5" 3.2" 3.3" 🚿 Regular watering
Jun 6.5" 1.9" 4.6" 🚿 Regular watering
Jul 6.5" 2.3" 4.2" 🚿 Regular watering
Aug 6.5" 2.6" 3.9" 🚿 Regular watering
Sep 6.5" 2.1" 4.4" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 2.1" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Bowman County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Napa Cabbage 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.

Napa Cabbage needs ~699 GDD — county provides 1,419 GDD Excellent fit

Napa Cabbage Planting Timeline — Bowman County, ND

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest July 10 Jul 10 – Aug 14
Fall Sowing July 2 Jul 2 – Jul 16

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

132 days in Bowman County

Growing Tips for Napa Cabbage in Bowman County

Direct sow Napa Cabbage outdoors after May 15 in Bowman County when soil has warmed and frost danger has passed.

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

General growing tips

Best grown as a fall crop. Direct sow in late summer, 60-70 days before first frost. Keep soil evenly moist. Bolt-resistant varieties are available for spring planting.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Napa Cabbage in Bowman County, ND?

Bowman County is in Zone 4b with an average last frost of May 15. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bowman County, ND?

Bowman County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 24.

🌱

Your Bowman County Garden Planner — Free

A 24-page printable planner built for Bowman County (Zone 4b). 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 Bowman County, ND. 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.