Blog

When to Plant Kai Lan in Rock County, NE

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.

Rock County, Nebraska is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 6, giving you a growing season of approximately 149 days.

At an elevation of 1,012 feet, Rock County receives approximately 32.4 inches of rainfall annually with predominantly loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Kai Lan to ensure they mature before fall.

Rock County, NE (Zone 4b) Short season
149 days
Last Spring Frost May 10
149 growing days
First Fall Frost October 6

Rock County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Start indoors: Mar 20 Transplant: May 1 🍅 Harvest: Jun 19 – Jul 17
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jun 28 – Jul 26
Safe Start (90%) ✓ Fits season (72 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jul 10 – Aug 7

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 Rock County

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

Soil pH

Your soil pH (6.7โ€“7.3) is within Kai Lan's preferred range (6.0โ€“7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). Annual compost additions will help Kai Lan.

How to Plant Kai Lan

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Kai Lan

3
successive plantings in your 149-day season

Sow every 5.1 weeks. Last sowing by Aug 07 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 138 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€” 0.9" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 3.8" 0" โ„๏ธ Dormant
May 4.3" 4.6" 0" โœ… Rainfall sufficient
Jun 4.3" 5.6" 0" โœ… Rainfall sufficient
Jul 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Aug 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Sep 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Oct 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Nov โ€” 1.1" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Rock 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 ~564 GDD — county provides 1,601 GDD Excellent fit

Kai Lan Planting Timeline โ€” Rock County, NE

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 โ€“ Apr 12
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow May 3 May 3 โ€“ May 24
Harvest June 28 Jun 28 โ€“ Jul 26
Fall Sowing July 14 Jul 14 โ€“ Jul 28

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
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

45โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

149 days in Rock County

Growing Tips for Kai Lan in Rock County

Direct sow Kai Lan outdoors after May 10 in Rock 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 Rock County, NE?

Rock County is in Zone 4b with an average last frost of May 10. Plan your Kai Lan planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rock County, NE?

Rock County, Nebraska is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rock County gardeners in Zone 4b 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 Rock County, NE. Local conditions may vary. Last updated: April 2026.