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When to Plant Napa Cabbage in Benson County, ND

Benson County, North Dakota Zone 4a May

Benson County, North Dakota gardeners: here's your May plan

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

Avg. last frost May 13
Avg. first frost September 27
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Move napa cabbage into the garden

    Frost risk is low now in Benson County, North Dakota. If you've been covering beds overnight, you can stop.

  2. Seed napa cabbage outdoors

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

Coming up in June — start thinking about
  • 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.

Benson County, North Dakota is in USDA Zone 4a. The average last spring frost is May 13 and the first fall frost is September 27, giving you a growing season of approximately 137 days.

At an elevation of 869 feet, Benson County receives approximately 34 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Benson County, ND (Zone 4a) Short season
137 days
Last Spring Frost May 13
137 growing days
First Fall Frost September 27
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Benson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Mar 26 Transplant: May 7 🍅 Harvest: Jul 2 – Aug 6
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Apr 1 Transplant: May 13 🍅 Harvest: Jul 8 – Aug 12
Safe Start (90%) ✓ Fits season (47 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jul 17 – Aug 21

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 Benson County

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

Soil pH

Your soil pH (6.6–7.6) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). Annual compost additions will help Napa Cabbage.

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 137-day season

Sow every 6.3 weeks. Last sowing by Jul 14 to harvest before frost.

For a dedicated fall crop, sow by Jul 05.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 558 gal / 100 sq ft

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 0.9" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 6.5" 5.4" 1.1" 💧 Light watering
Jun 6.5" 5.2" 1.3" 💧 Light watering
Jul 6.5" 3.9" 2.6" 💧 Light watering
Aug 6.5" 4.1" 2.4" 💧 Light watering
Sep 6.5" 3.1" 3.4" 🚿 Regular watering
Oct 2" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Benson 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 ~601 GDD — county provides 1,267 GDD Excellent fit

Napa Cabbage Planting Timeline — Benson County, ND

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 6 May 6 – May 27
Harvest July 8 Jul 8 – Aug 12
Fall Sowing July 5 Jul 5 – Jul 19

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
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

137 days in Benson County

Growing Tips for Napa Cabbage in Benson County

Direct sow Napa Cabbage outdoors after May 13 in Benson 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 Benson County, ND?

Benson County is in Zone 4a with an average last frost of May 13. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benson County, ND?

Benson County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 13 and first fall frost is September 27.

🌱

Your Benson County Garden Planner — Free

A 24-page printable planner built for Benson County (Zone 4a). 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 Benson 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.