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When to Plant Kai Lan in Green County, WI

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.

Green County, Wisconsin is in USDA Zone 5a. The average last spring frost is April 27 and the first fall frost is October 11, giving you a growing season of approximately 167 days.

At an elevation of 1,235 feet, Green County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Kai Lan to ensure they mature before fall.

Green County, WI (Zone 5a) Moderate season
167 days
Last Spring Frost April 27
167 growing days
First Fall Frost October 11

Green County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 10 – Jul 8
Recommended (50%) ✓ Fits season (90 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 15 – Jul 13
Safe Start (90%) ✓ Fits season (90 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 30 – Jul 28

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 663 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Kai Lan needs ~643 GDD — county provides 2,045 GDD Excellent fit

Kai Lan Planting Timeline โ€” Green County, WI

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 โ€“ Apr 6
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 13 Apr 13 โ€“ May 4
Fall Sowing August 2 Aug 2 โ€“ Aug 16
Harvest June 15 Jun 15 โ€“ Jul 13

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

45โ€“60 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

167 days

Growing Tips for Green County

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

Level Up Your Garden

Frequently Asked Questions

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

Green County is in Zone 5a with an average last frost of April 27. Plan your Kai Lan planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Green County, WI?

Green County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is April 27 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Green County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Green County, WI. Local conditions may vary. Last updated: April 2026.