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When to Plant Kai Lan in Marion County, IN

Marion County, Indiana Zone 6b May

This month in Marion County, Indiana

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 14
Avg. first frost October 21
Soil temp (4") 61°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Time to start kai lan inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

June prep starts now
  • First harvests: kai lan

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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.

Marion County, Indiana is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 21, giving you a growing season of approximately 190 days.

At an elevation of 1,343 feet, Marion County receives approximately 41.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Kai Lan during the growing season.

Marion County, IN (Zone 6b) Moderate season
190 days
Last Spring Frost April 14
190 growing days
First Fall Frost October 21
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Marion County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (114 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 27 – Jun 24
Recommended (50%) ✓ Fits season (113 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 2 – Jun 30
Safe Start (90%) ✓ Fits season (107 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jun 19 – Jul 17

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 Marion County

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

Soil pH

Your soil pH (6.0–7.0) is within Kai Lan's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Marion County is excellent for Kai Lan — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Kai Lan.

Organic Matter

Organic matter is excellent (4.3%) — 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

5
successive plantings in your 190-day season

Sow every 5.1 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 632 gal / 100 sq ft

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 1.7" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Marion County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 2,755 GDD Excellent fit

Kai Lan Planting Timeline — Marion County, IN

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest June 2 Jun 2 – Jun 30
Fall Sowing August 12 Aug 12 – Aug 26

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

190 days in Marion County

Growing Tips for Kai Lan in Marion County

Direct sow Kai Lan outdoors after April 14 in Marion County when soil has warmed and frost danger has passed.

Your generous 190.0-day season in Marion 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 Marion County, IN?

Marion County is in Zone 6b with an average last frost of April 14. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marion County, IN?

Marion County, Indiana is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 21.

🌱

Your Marion County Garden Planner — Free

A 24-page printable planner built for Marion County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Marion County, IN. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.