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When to Plant Napa Cabbage in Oconto County, WI

Oconto County, Wisconsin Zone 4b April

This month in Oconto County, Wisconsin

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

Avg. last frost May 9
Avg. first frost October 4
Soil temp (4") 40°F
Watering Moderate
Pest pressure Low
Daylight 13.3 hrs
May prep starts now
  • Transplants going out: napa cabbage
  • Direct-sowing: 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.

Oconto County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 9 and the first fall frost is October 4, giving you a growing season of approximately 148 days.

At an elevation of 794 feet, Oconto County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Oconto County, WI (Zone 4b) Short season
148 days
Last Spring Frost May 9
148 growing days
First Fall Frost October 4

Oconto County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Mar 22 Transplant: May 3 🍅 Harvest: Jun 28 – Aug 2
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Jul 4 – Aug 8
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Apr 14 Transplant: May 26 🍅 Harvest: Jul 21 – Aug 25

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 Oconto County

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

Soil pH

Your soil pH (6.0–7.0) is within Napa Cabbage's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — 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

3
successive plantings in your 148-day season

Sow every 6.3 weeks. Last sowing by Jul 21 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.1″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 684 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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 6.5" 4.1" 2.4" 💧 Light watering
Jun 6.5" 4.7" 1.8" 💧 Light watering
Jul 6.5" 4.6" 1.9" 💧 Light watering
Aug 6.5" 4.1" 2.4" 💧 Light watering
Sep 6.5" 3.3" 3.2" 💧 Light watering
Oct 6.5" 2.7" 3.8" 🚿 Regular watering
Nov 2.8" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Oconto 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 ~650 GDD — county provides 1,480 GDD Excellent fit

Napa Cabbage Planting Timeline — Oconto County, WI

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest July 4 Jul 4 – Aug 8
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
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 · 1-2 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

148 days in Oconto County

Growing Tips for Napa Cabbage in Oconto County

Direct sow Napa Cabbage outdoors after May 09 in Oconto 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 Oconto County, WI?

Oconto County is in Zone 4b with an average last frost of May 9. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Oconto County, WI?

Oconto County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 9 and first fall frost is October 4.

🌱

Your Oconto County Garden Planner — Free

A 24-page printable planner built for Oconto 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 Oconto County, WI. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.