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When to Plant Chinese Cabbage in St. Clair County, IL

St. Clair County, Illinois Zone 7a May

May in the garden — St. Clair County, Illinois

Here's what deserves your attention in St. Clair County, Illinois this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 2
Avg. first frost November 2
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Indoor seed-starting week for chinese cabbage

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Start harvesting chinese cabbage

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Coming up in June — start thinking about
  • First harvests: chinese cabbage

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Chinese cabbage (Napa cabbage) forms elongated, barrel-shaped heads with tender, mild-flavored leaves. It is a staple in Asian cooking, particularly for kimchi.

St. Clair County, Illinois is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.

At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Chinese Cabbage during the growing season.

St. Clair County, IL (Zone 7a) Long season
214 days
Last Spring Frost April 2
214 growing days
First Fall Frost November 2

St. Clair County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Feb 19 Transplant: Mar 26 🍅 Harvest: May 21 – Jun 18
Recommended (50%) ✓ Fits season (130 days to spare)
Start indoors: Feb 26 Transplant: Apr 2 🍅 Harvest: May 28 – Jun 25
Safe Start (90%) ✓ Fits season (136 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Jul 10

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 St. Clair County

How your county's soil matches Chinese Cabbage's growing requirements.

Soil pH

Your soil pH (6.0–7.3) is within Chinese Cabbage's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in St. Clair County is excellent for Chinese Cabbage — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Chinese Cabbage will thrive.

How to Plant Chinese Cabbage

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Chinese Cabbage

5
successive plantings in your 214-day season

Sow every 5.7 weeks. Last sowing by Aug 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 24.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,899 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Chinese Cabbage

Chinese Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Chinese Cabbage Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 6.5" 3.2" 3.3" 🚿 Regular watering
May 6.5" 3.8" 2.7" 💧 Light watering
Jun 6.5" 4" 2.5" 💧 Light watering
Jul 6.5" 3.8" 2.7" 💧 Light watering
Aug 6.5" 3.9" 2.6" 💧 Light watering
Sep 6.5" 3.3" 3.2" 💧 Light watering
Oct 6.5" 2.5" 4" 🚿 Regular watering
Nov 6.5" 2.4" 4.1" 🚿 Regular watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in St. Clair County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Chinese Cabbage 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.

Chinese Cabbage needs ~1,005 GDD — county provides 3,584 GDD Excellent fit

Chinese Cabbage Planting Timeline — St. Clair County, IL

Chinese Cabbage Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors April 2 Apr 2 – Apr 16
Direct Sow March 19 Mar 19 – Apr 9
Harvest May 28 May 28 – Jun 25
Fall Sowing August 24 Aug 24 – Sep 7

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for Chinese Cabbage in St. Clair County

Direct sow Chinese Cabbage outdoors after April 02 in St. Clair County when soil has warmed and frost danger has passed.

Common pests for Chinese Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Best grown as a fall crop to avoid bolting. Start seeds indoors or direct sow in late summer. Keep soil consistently moist and provide shade in warm weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chinese Cabbage in St. Clair County, IL?

St. Clair County is in Zone 7a with an average last frost of April 2. Plan your Chinese Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Clair County, IL?

St. Clair County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 2 and first fall frost is November 2.

🌱

Your St. Clair County Garden Planner — Free

A 24-page printable planner built for St. Clair County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for St. Clair 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.