Blog

When to Plant Broccoli Rabe in Lake County, IL

Lake County, Illinois Zone 6a May

May in Lake County, Illinois — your action list

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

Avg. last frost April 21
Avg. first frost October 20
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Begin indoor sowing: broccoli rabe

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

To set up a strong June, finish these tasks
  • First harvests: broccoli rabe

Instant PDF download. No spam, unsubscribe any time.

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

Lake County, Illinois is in USDA Zone 6a. The average last spring frost is April 21 and the first fall frost is October 20, giving you a growing season of approximately 182 days.

At an elevation of 1,080 feet, Lake County receives approximately 33.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Broccoli Rabe to ensure they mature before fall.

Lake County, IL (Zone 6a) Moderate season
182 days
Last Spring Frost April 21
182 growing days
First Fall Frost October 20

Lake County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (101 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: May 28 – Jul 2
Recommended (50%) ✓ Fits season (105 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jun 2 – Jul 7
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 20 – 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 Lake County

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

Soil pH

Your soil pH (6.2–6.9) is within Broccoli Rabe's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Broccoli Rabe.

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 182-day season

Sow every 4.6 weeks. Last sowing by Aug 21 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 52 gal / 100 sq ft
Drought risk

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

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 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 3.5" 3.3" 0.2" 💧 Light watering
May 3.5" 3.9" 0" ✅ Rainfall sufficient
Jun 3.5" 4.4" 0" ✅ Rainfall sufficient
Jul 3.5" 3.3" 0.2" 💧 Light watering
Aug 3.5" 3.4" 0.1" 💧 Light watering
Sep 3.5" 3.3" 0.2" 💧 Light watering
Oct 3.5" 2.8" 0.7" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lake 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 ~612 GDD — county provides 2,229 GDD Excellent fit

Broccoli Rabe Planting Timeline — Lake County, IL

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 7 Apr 7 – Apr 28
Harvest June 2 Jun 2 – Jul 7
Fall Sowing August 11 Aug 11 – Aug 25

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
June Harvest
July Harvest
August Fall Sowing
September
October
November
December

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

182 days in Lake County

Growing Tips for Broccoli Rabe in Lake County

Direct sow Broccoli Rabe outdoors after April 21 in Lake County when soil has warmed and frost danger has passed.

Your generous 182.0-day season in Lake 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 Lake County, IL?

Lake County is in Zone 6a with an average last frost of April 21. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, IL?

Lake County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 21 and first fall frost is October 20.

🌱

Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake 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.

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 Lake 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.