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When to Plant Broccoli Rabe in McDonough County, IL

McDonough County, Illinois Zone 6a May

Your May game plan for McDonough County, Illinois

Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 17
Avg. first frost October 17
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Fire up the seed-starting tray: broccoli rabe

    You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Bring in the broccoli rabe

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before June arrives, get these ready
  • First harvests: broccoli rabe

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Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.

McDonough County, Illinois is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 17, giving you a growing season of approximately 183 days.

At an elevation of 738 feet, McDonough County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.

McDonough County, IL (Zone 6a) Moderate season
183 days
Last Spring Frost April 17
183 growing days
First Fall Frost October 17
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McDonough County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 23 – Jun 27
Recommended (50%) ✓ Fits season (106 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: May 29 – Jul 3
Safe Start (90%) ✓ Fits season (107 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 11 – Jul 16

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 McDonough County

How your county's soil matches Broccoli Rabe's growing requirements.

Soil pH

Your soil pH (6.2–7.3) is within Broccoli Rabe's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Broccoli Rabe.

Organic Matter

Organic matter is excellent (4.3%) — Broccoli Rabe will thrive.

How to Plant Broccoli Rabe

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 Broccoli Rabe

5
successive plantings in your 183-day season

Sow every 4.6 weeks. Last sowing by Aug 18 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 300 gal / 100 sq ft

Monthly Watering Guide for Broccoli Rabe

Broccoli Rabe needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Rabe Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.5" 3.2" 0.3" 💧 Light watering
May 3.5" 4.8" 0" ✅ Rainfall sufficient
Jun 3.5" 4.1" 0" ✅ Rainfall sufficient
Jul 3.5" 4.6" 0" ✅ Rainfall sufficient
Aug 3.5" 3.8" 0" ✅ Rainfall sufficient
Sep 3.5" 3.5" 0" ✅ Rainfall sufficient
Oct 3.5" 3.3" 0.2" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Broccoli Rabe 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.

Broccoli Rabe needs ~650 GDD — county provides 2,379 GDD Excellent fit

Broccoli Rabe Planting Timeline — McDonough County, IL

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 3 Apr 3 – Apr 24
Harvest May 29 May 29 – Jul 3
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 Transplant Outdoors Harvest
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

183 days in McDonough County

Growing Tips for Broccoli Rabe in McDonough County

Direct sow Broccoli Rabe outdoors after April 17 in McDonough County when soil has warmed and frost danger has passed.

Your generous 183.0-day season in McDonough County allows multiple plantings of Broccoli Rabe. Sow every 20.0 days for continuous harvest.

Common pests for Broccoli Rabe 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 small yellow flower buds first appear but before they open. Cut the main shoot first to encourage side shoots.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Broccoli Rabe in McDonough County, IL?

McDonough County is in Zone 6a with an average last frost of April 17. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is McDonough County, IL?

McDonough County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 17.

🌱

Your McDonough County Garden Planner — Free

A 24-page printable planner built for McDonough 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 McDonough 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.