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When to Plant Napa Cabbage in Florence County, WI

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.

Florence County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.

At an elevation of 1,147 feet, Florence County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.

Florence County, WI (Zone 4a) Short season
118 days
Last Spring Frost May 26
118 growing days
First Fall Frost September 21

Florence County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Jul 15 – Aug 19
Recommended (50%) ✓ Fits season (27 days to spare)
Start indoors: Apr 14 Transplant: May 26 🍅 Harvest: Jul 21 – Aug 25
Safe Start (90%) ✓ Fits season (28 days to spare)
Start indoors: Apr 30 Transplant: Jun 11 🍅 Harvest: Aug 6 – Sep 10

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 Florence County

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

Soil pH

Your soil pH (5.8โ€“6.8) overlaps with Napa Cabbage's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Florence County is excellent for Napa Cabbage โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) โ€” 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 118-day season

Sow every 6.3 weeks. Last sowing by Jul 08 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.2″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 286 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 โ€” 1.2" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.6" 0" โ„๏ธ Dormant
Apr โ€” 3.4" 0" โ„๏ธ Dormant
May 6.5" 4.4" 2.1" ๐Ÿ’ง Light watering
Jun 6.5" 4.4" 2.1" ๐Ÿ’ง Light watering
Jul 6.5" 3.2" 3.3" ๐Ÿšฟ Regular watering
Aug 6.5" 4" 2.5" ๐Ÿ’ง Light watering
Sep 6.5" 2.9" 3.6" ๐Ÿšฟ Regular watering
Oct โ€” 2.7" 0" โ„๏ธ Dormant
Nov โ€” 2.4" 0" โ„๏ธ Dormant
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Florence County). Supplement amounts are based on average rainfall โ€” 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" 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.

Napa Cabbage needs ~748 GDD — county provides 1,357 GDD Excellent fit

Napa Cabbage Planting Timeline โ€” Florence County, WI

Napa Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 โ€“ Apr 28
Transplant Outdoors May 26 May 26 โ€“ Jun 9
Direct Sow May 19 May 19 โ€“ Jun 9
Harvest July 21 Jul 21 โ€“ Aug 25
Fall Sowing June 29 Jun 29 โ€“ Jul 13

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1.5"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

55โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

118 days in Florence County

Growing Tips for Napa Cabbage in Florence County

Direct sow Napa Cabbage outdoors after May 26 in Florence 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 Florence County, WI?

Florence County is in Zone 4a with an average last frost of May 26. Plan your Napa Cabbage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Florence County, WI?

Florence County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 26 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Florence County, WI. Local conditions may vary. Last updated: April 2026.