Blog

When to Plant Kai Lan in Roseau County, MN

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.

Roseau County, Minnesota is in USDA Zone 3a. The average last spring frost is May 21 and the first fall frost is September 22, giving you a growing season of approximately 124 days.

At an elevation of 655 feet, Roseau County receives approximately 32 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Kai Lan to ensure they mature before fall.

Roseau County, MN (Zone 3a) Short season
124 days
Last Spring Frost May 21
124 growing days
First Fall Frost September 22

Roseau County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 29 – Jul 27
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Jul 9 – Aug 6
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Apr 23 Transplant: Jun 4 🍅 Harvest: Jul 23 – Aug 20

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Kai Lan needs ~486 GDD — county provides 1,147 GDD Excellent fit

Kai Lan Planting Timeline โ€” Roseau County, MN

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 โ€“ Apr 23
Transplant Outdoors May 21 May 21 โ€“ Jun 4
Direct Sow May 14 May 14 โ€“ Jun 4
Fall Sowing June 30 Jun 30 โ€“ Jul 14
Harvest July 9 Jul 9 โ€“ Aug 6

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

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 3a

Growing Season

124 days

Growing Tips for Roseau 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 Roseau County, MN?

Roseau County is in Zone 3a with an average last frost of May 21. Plan your Kai Lan planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Roseau County, MN?

Roseau County, Minnesota is in USDA Hardiness Zone 3a. The average last spring frost is May 21 and first fall frost is September 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Roseau County gardeners in Zone 3a 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 Roseau County, MN. Local conditions may vary. Last updated: April 2026.