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When to plant Cabbage in Thayer, IL

Plant Cabbage in Thayer after April 15; the prime window is April 1–April 22. A second sowing from August 8 to August 22 extends the harvest into fall.

When to Plant Cabbage in Thayer, IL

Cabbage
Sangamon County, Illinois Zone 6a June

Your June gardening checklist

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

Avg. last frost April 15
Avg. first frost October 17
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. It's harvest week for cabbage

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Looking ahead to July
  • First harvests: cabbage

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Cabbage is a versatile cool-season crop that forms dense, leafy heads in green, red, or savoy varieties. It is a staple for coleslaw, sauerkraut, and many global cuisines.

Thayer, Illinois is in USDA Zone 6a. The average last spring frost is April 15 and the first fall frost is October 17, giving you a growing season of approximately 185 days.

At an elevation of 1,204 feet, Sangamon County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Cabbage during the growing season.

Thayer, IL (Zone 6a) Moderate season
185 days
Last Spring Frost April 15
185 growing days
First Fall Frost October 17

Thayer Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Cabbage Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 11 – Aug 6
Recommended (50%) ✓ Fits season (66 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jun 17 – Aug 12
Safe Start (90%) ✓ Fits season (67 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 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 Thayer

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

Soil pH

Your soil pH (6.2–7.2) is within Cabbage's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Cabbage will thrive.

How to Plant 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 Cabbage

3
successive plantings in your 185-day season

Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

Cabbage Water Budget

Plant needs
0.9″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Cabbage

Cabbage needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Cabbage Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.9" 4.5" 0" ✅ Rainfall sufficient
May 3.9" 4.5" 0" ✅ Rainfall sufficient
Jun 3.9" 5.8" 0" ✅ Rainfall sufficient
Jul 3.9" 4.1" 0" ✅ Rainfall sufficient
Aug 3.9" 4.3" 0" ✅ Rainfall sufficient
Sep 3.9" 3.3" 0.6" 💧 Light watering
Oct 3.9" 3.3" 0.6" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

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

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.

Cabbage needs ~1,100 GDD — county provides 2,543 GDD Excellent fit

Cabbage Planting Timeline — Thayer, IL

Cabbage Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest June 17 Jun 17 – Aug 12
Fall Sowing August 8 Aug 8 – Aug 22

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

185 days in Sangamon County

Growing Tips for Cabbage in Thayer

Direct sow Cabbage outdoors after April 15 in Sangamon County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 4-6 weeks before last frost. Space plants 18-24 inches apart. Keep soil evenly moist to prevent heads from splitting.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

When should I plant Cabbage in Thayer, IL?

In Thayer, IL, plant Cabbage after the last frost (around April 15) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Thayer, IL for Cabbage?

Thayer sits in USDA Zone 6a. Cabbage grows reliably in zones 1a through 10b, so it's a good fit here.

Can Cabbage grow in Thayer's climate?

Yes — Cabbage grows well in Thayer's temperate climate. Thayer averages a 185-day frost-free season, with last frost around April 15 and first frost around October 17.

🌱

Your Sangamon County Garden Planner — Free

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