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When to plant Kai Lan in Hamilton County, IL

Plant Kai Lan in Hamilton County from March 26 to April 16 in spring. Hamilton County sits in USDA Zone 6b, with last frost around April 9 and first frost on October 23. A second sowing from August 14 to August 28 extends the harvest into fall.

When to Plant Kai Lan in Hamilton County, IL

Hamilton County, Illinois Zone 6b July

July to-do list for Hamilton County, Illinois

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

Avg. last frost April 9
Avg. first frost October 23
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 14.4 hrs

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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.

Hamilton County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 23, giving you a growing season of approximately 197 days.

At an elevation of 524 feet, Hamilton County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Kai Lan during the growing season.

Hamilton County, IL (Zone 6b) Moderate season
197 days
Last Spring Frost April 9
197 growing days
First Fall Frost October 23

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Kai Lan Planting Risk Windows

Early Start (70% safe) ✓ Fits season (120 days to spare)
Start indoors: Feb 27 Transplant: Apr 3 🍅 Harvest: May 22 – Jun 19
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: May 28 – Jun 25
Safe Start (90%) ✓ Fits season (130 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: Jun 8 – Jul 6

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 Hamilton County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Kai Lan's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — 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 197-day season

Sow every 5.1 weeks. Last sowing by Aug 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Kai Lan 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 355 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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hamilton 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 ~919 GDD — county provides 3,447 GDD Excellent fit

Kai Lan Planting Timeline — Hamilton County, IL

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow March 26 Mar 26 – Apr 16
Harvest May 28 May 28 – Jun 25
Fall Sowing August 14 Aug 14 – Aug 28

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 Harvest
June Harvest
July
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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

197 days in Hamilton County

Growing Tips for Kai Lan in Hamilton County

Direct sow Kai Lan outdoors after April 09 in Hamilton County when soil has warmed and frost danger has passed.

Your generous 197.0-day season in Hamilton 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 Hamilton County, IL?

Hamilton County is in Zone 6b with an average last frost of April 9. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, IL?

Hamilton County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 23.

When should I plant Kai Lan in Hamilton County, IL?

In Hamilton County, IL, plant Kai Lan after the last frost (around April 9) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Hamilton County, IL for Kai Lan?

Hamilton County sits in USDA Zone 6b. Kai Lan grows reliably in zones 2a through 11b, so it's a good fit here.

Can Kai Lan grow in Hamilton County's climate?

Yes — Kai Lan grows well in Hamilton County's temperate climate. Hamilton County averages a 197-day frost-free season, with last frost around April 9 and first frost around October 23.

🌱

Your Hamilton County Garden Planner — Free

A 22-page printable planner built for Hamilton 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 Hamilton County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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