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When to Plant Kai Lan in Door County, WI

Door County, Wisconsin Zone 5a April

Door County, Wisconsin gardeners: here's your April plan

We've pulled the most time-sensitive tasks for Door County, Wisconsin this April and put them front and centre. Tackle them in order.

Avg. last frost May 11
Avg. first frost October 8
Soil temp (4") 43°F
Watering Moderate
Pest pressure Low
Daylight 13.3 hrs
  1. Plant kai lan from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

Looking ahead to May
  • Transplants going out: kai lan

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Kai lan (Chinese broccoli) is a brassica grown for its thick, glossy stems and small flower buds. It has a slightly bitter, broccoli-like flavor essential in Cantonese cooking.

Door County, Wisconsin is in USDA Zone 5a. The average last spring frost is May 11 and the first fall frost is October 8, giving you a growing season of approximately 150 days.

At an elevation of 564 feet, Door County receives approximately 41.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Kai Lan during the growing season.

Door County, WI (Zone 5a) Moderate season
150 days
Last Spring Frost May 11
150 growing days
First Fall Frost October 8
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Door County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: Jun 23 – Jul 21
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 29 – Jul 27
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jul 14 – Aug 11

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 Door County

How your county's soil matches Kai Lan's growing requirements.

Soil pH

Your soil pH (6.0–7.3) is within Kai Lan's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Door County is excellent for Kai Lan — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Kai Lan.

Organic Matter

Organic matter is excellent (4.7%) — Kai Lan will thrive.

How to Plant Kai Lan

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Kai Lan

3
successive plantings in your 150-day season

Sow every 5.1 weeks. Last sowing by Aug 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 30.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 208 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Kai Lan

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

Month Kai Lan Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

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

Kai Lan 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.

Kai Lan needs ~801 GDD — county provides 2,287 GDD Excellent fit

Kai Lan Planting Timeline — Door County, WI

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 11 May 11 – May 25
Direct Sow April 27 Apr 27 – May 18
Harvest June 29 Jun 29 – Jul 27
Fall Sowing July 30 Jul 30 – Aug 13

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

150 days in Door County

Growing Tips for Kai Lan in Door County

Direct sow Kai Lan outdoors after May 11 in Door County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow in spring or fall. Harvest when flower buds first appear but before they open. Cut stems at the base to encourage side shoots. Prefers cool weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kai Lan in Door County, WI?

Door County is in Zone 5a with an average last frost of May 11. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Door County, WI?

Door County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 11 and first fall frost is October 8.

🌱

Your Door County Garden Planner — Free

A 24-page printable planner built for Door County (Zone 5a). 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 Door 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.