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When to Plant Kai Lan in Boone County, IN

Boone County, Indiana Zone 6a May

Boone County, Indiana gardeners: here's your May plan

Here's what deserves your attention in Boone County, Indiana this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost April 22
Avg. first frost October 15
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Sow kai lan in trays indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

To set up a strong June, finish these tasks
  • 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.

Boone County, Indiana is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 15, giving you a growing season of approximately 176 days.

At an elevation of 850 feet, Boone County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Kai Lan to ensure they mature before fall.

Boone County, IN (Zone 6a) Moderate season
176 days
Last Spring Frost April 22
176 growing days
First Fall Frost October 15

Boone County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 2 – Jun 30
Recommended (50%) ✓ Fits season (99 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 10 – Jul 8
Safe Start (90%) ✓ Fits season (96 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jun 25 – Jul 23

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 Boone County

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

Soil pH

Your soil pH (6.2–6.8) is within Kai Lan's preferred range (6.0–7.5).

Soil Texture

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

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

4
successive plantings in your 176-day season

Sow every 5.1 weeks. Last sowing by Aug 16 to harvest before frost.

For a dedicated fall crop, sow by Aug 06.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 296 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Boone 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 ~643 GDD — county provides 2,156 GDD Excellent fit

Kai Lan Planting Timeline — Boone County, IN

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 8 Apr 8 – Apr 29
Harvest June 10 Jun 10 – Jul 8
Fall Sowing August 6 Aug 6 – Aug 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

176 days in Boone County

Growing Tips for Kai Lan in Boone County

Direct sow Kai Lan outdoors after April 22 in Boone County when soil has warmed and frost danger has passed.

Your generous 176.0-day season in Boone 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 Boone County, IN?

Boone County is in Zone 6a with an average last frost of April 22. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boone County, IN?

Boone County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 15.

🌱

Your Boone County Garden Planner — Free

A 24-page printable planner built for Boone County (Zone 6a). 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 Boone 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.