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When to Plant Kai Lan in Oneida County, ID

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.

Oneida County, Idaho is in USDA Zone 5a. The average last spring frost is May 23 and the first fall frost is September 20, giving you a growing season of approximately 120 days.

At an elevation of 8,042 feet, Oneida County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Kai Lan during the growing season. With low rainfall, drip irrigation is essential for growing Kai Lan successfully. Mulch heavily to conserve soil moisture.

Oneida County, ID (Zone 5a) Short season
120 days
Last Spring Frost May 23
120 growing days
First Fall Frost September 20

Oneida County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 30 – Jul 28
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Jul 11 – Aug 8
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: May 11 Transplant: Jun 15 🍅 Harvest: Aug 3 – Aug 31

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
0.6″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 841 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Kai Lan needs ~722 GDD — county provides 1,650 GDD Excellent fit

Kai Lan Planting Timeline โ€” Oneida County, ID

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 โ€“ May 2
Transplant Outdoors May 23 May 23 โ€“ Jun 6
Direct Sow May 9 May 9 โ€“ May 30
Fall Sowing July 12 Jul 12 โ€“ Jul 26
Harvest July 11 Jul 11 โ€“ Aug 8

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 Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors
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 5a

Growing Season

120 days

Growing Tips for Oneida 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 Oneida County, ID?

Oneida County is in Zone 5a with an average last frost of May 23. Plan your Kai Lan planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Oneida County, ID?

Oneida County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 23 and first fall frost is September 20.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Oneida 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 Oneida County, ID. Local conditions may vary. Last updated: April 2026.