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When to Plant Kai Lan in Jo Daviess County, IL

Jo Daviess County, Illinois Zone 5a May

Your May planting checklist for Jo Daviess County, Illinois

Here's what deserves your attention in Jo Daviess County, Illinois this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost April 24
Avg. first frost October 11
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Indoor seed-starting week for kai lan

    These need a head start before your last frost (April 24). Sow into cells now so you're ready to transplant in a few weeks.

Coming up in June — start thinking about
  • 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.

Jo Daviess County, Illinois is in USDA Zone 5a. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 501 feet, Jo Daviess County receives approximately 35.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Kai Lan during the growing season.

Jo Daviess County, IL (Zone 5a) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11
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Jo Daviess County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jun 4 – Jul 2
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Mar 20 Transplant: Apr 24 🍅 Harvest: Jun 12 – Jul 10
Safe Start (90%) ✓ Fits season (92 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 27 – Jul 25

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 Jo Daviess County

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

Soil pH

Your soil pH (5.9–7.3) overlaps with Kai Lan's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 170-day season

Sow every 5.1 weeks. Last sowing by Aug 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 02.

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 190 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 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jo Daviess 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 ~801 GDD — county provides 2,592 GDD Excellent fit

Kai Lan Planting Timeline — Jo Daviess County, IL

Kai Lan Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 10 Apr 10 – May 1
Harvest June 12 Jun 12 – Jul 10
Fall Sowing August 2 Aug 2 – Aug 16

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 Direct Sow
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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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 5a

📆 Growing Season

170 days in Jo Daviess County

Growing Tips for Kai Lan in Jo Daviess County

Direct sow Kai Lan outdoors after April 24 in Jo Daviess County when soil has warmed and frost danger has passed.

Your generous 170.0-day season in Jo Daviess 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 Jo Daviess County, IL?

Jo Daviess County is in Zone 5a with an average last frost of April 24. Plan your Kai Lan planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jo Daviess County, IL?

Jo Daviess County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 24 and first fall frost is October 11.

🌱

Your Jo Daviess County Garden Planner — Free

A 24-page printable planner built for Jo Daviess County (Zone 5a). 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 Jo Daviess County, IL. 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.