Blog

When to Plant Kai Lan in Doniphan County, KS

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.

Doniphan County, Kansas is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 18, giving you a growing season of approximately 184 days.

At an elevation of 491 feet, Doniphan County receives approximately 26.7 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, providing good warmth for Kai Lan during the growing season.

Doniphan County, KS (Zone 5b) Moderate season
184 days
Last Spring Frost April 17
184 growing days
First Fall Frost October 18

Doniphan County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (104 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 31 – Jun 28
Recommended (50%) ✓ Fits season (107 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 5 – Jul 3
Safe Start (90%) ✓ Fits season (108 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 18 – Jul 16

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 Doniphan County

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

Soil pH

Your soil pH (6.8โ€“7.3) is within Kai Lan's preferred range (6.0โ€“7.5).

Soil Texture

The loam soil in Doniphan County is excellent for Kai Lan โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Kai Lan.

Organic Matter

Organic matter is excellent (4.1%) โ€” 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

4
successive plantings in your 184-day season

Sow every 5.1 weeks. Last sowing by Aug 19 to harvest before frost.

For a dedicated fall crop, sow by Aug 09.

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 1,357 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 0.8" 0" โ„๏ธ Dormant
Feb โ€” 0.9" 0" โ„๏ธ Dormant
Mar โ€” 1.7" 0" โ„๏ธ Dormant
Apr 4.3" 2.6" 1.7" ๐Ÿ’ง Light watering
May 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Jun 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Jul 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Aug 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Sep 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Oct 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Nov โ€” 0.8" 0" โ„๏ธ Dormant
Dec โ€” 0.6" 0" โ„๏ธ Dormant

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

Kai Lan needs ~761 GDD — county provides 2,668 GDD Excellent fit

Kai Lan Planting Timeline โ€” Doniphan County, KS

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 โ€“ Mar 27
Transplant Outdoors April 17 Apr 17 โ€“ May 1
Direct Sow April 3 Apr 3 โ€“ Apr 24
Harvest June 5 Jun 5 โ€“ Jul 3
Fall Sowing August 9 Aug 9 โ€“ Aug 23

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

45โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

184 days in Doniphan County

Growing Tips for Kai Lan in Doniphan County

Direct sow Kai Lan outdoors after April 17 in Doniphan County when soil has warmed and frost danger has passed.

Your generous 184.0-day season in Doniphan County allows multiple plantings of Kai Lan. Sow every 22.0 days for continuous harvest.

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 Doniphan County, KS?

Doniphan County is in Zone 5b with an average last frost of April 17. Plan your Kai Lan planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Doniphan County, KS?

Doniphan County, Kansas is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Doniphan County gardeners in Zone 5b 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 Doniphan County, KS. Local conditions may vary. Last updated: April 2026.