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When to plant Broccoli in Kell, IL

In Zone 6b (Kell), direct-sow Broccoli between March 27 and April 17 for spring, after the April 10 last-frost mark. A second sowing from August 10 to August 24 extends the harvest into fall.

When to Plant Broccoli in Kell, IL

Broccoli
Marion County, Illinois Zone 6b July

Your July game plan for Marion County, Illinois

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Marion County, Illinois.

Avg. last frost April 10
Avg. first frost October 19
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.4 hrs
  1. Harvest broccoli as they ripen

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

A few tasks this July that'll pay off in August
  • Fall sowing: broccoli

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Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

Kell, Illinois is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 19, giving you a growing season of approximately 192 days.

At an elevation of 964 feet, Marion County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Broccoli during the growing season.

Kell, IL (Zone 6b) Moderate season
192 days
Last Spring Frost April 10
192 growing days
First Fall Frost October 19

Kell Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Broccoli Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: Jun 7 – Jul 19
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jun 12 – Jul 24
Safe Start (90%) ✓ Fits season (89 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: Jun 22 – Aug 3

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 Kell

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

Soil pH

Your soil pH (6.1–7.0) is within Broccoli's preferred range (6.0–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Broccoli.

Organic Matter

Organic matter is excellent (4.4%) — Broccoli will thrive.

How to Plant Broccoli

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

3
successive plantings in your 192-day season

Sow every 6.9 weeks. Last sowing by Jul 21 to harvest before frost.

For a dedicated fall crop, sow by Aug 10.

Broccoli Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 708 gal / 100 sq ft

Monthly Watering Guide for Broccoli

Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Broccoli 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 needs ~1,256 GDD — county provides 3,216 GDD Excellent fit

Broccoli Planting Timeline — Kell, IL

Broccoli Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 10 Apr 10 – Apr 24
Direct Sow March 27 Mar 27 – Apr 17
Harvest June 12 Jun 12 – Jul 24
Fall Sowing August 10 Aug 10 – Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

192 days in Marion County

Growing Tips for Broccoli in Kell

Direct sow Broccoli outdoors after April 10 in Marion County when soil has warmed and frost danger has passed.

Common pests for Broccoli 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 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.

When should I plant Broccoli in Kell, IL?

In Kell, IL, plant Broccoli after the last frost (around April 10) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Kell, IL for Broccoli?

Kell sits in USDA Zone 6b. Broccoli grows reliably in zones 2a through 11b, so it's a good fit here.

Can Broccoli grow in Kell's climate?

Yes — Broccoli grows well in Kell's temperate climate. Kell averages a 192-day frost-free season, with last frost around April 10 and first frost around October 19.

🌱

Your Marion County Garden Planner — Free

A 22-page printable planner built for Marion County (Zone 6b). 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 Marion County, IL. Local conditions may vary. Last updated: July 2026.