When to plant Broccoli in Marshall County, IL
In Zone 5b (Marshall County), direct-sow Broccoli between April 7 and April 28 for spring, after the April 21 last-frost mark. A second sowing from August 4 to August 18 extends the harvest into fall.
When to Plant Broccoli in Marshall County, IL
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.
Marshall County, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.
At an elevation of 1,177 feet, Marshall County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Broccoli to ensure they mature before fall.
Marshall County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.8
Drainage
Well Drained
How Much Broccoli to Grow
For a family of 4, plant approximately 12 broccoli plants in about 24 sq ft. In Marshall County's 175-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| May | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 3" | 1.3" | 💧 Light watering |
| Aug | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Sep | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Marshall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Broccoli Planting Timeline — Marshall County, IL
Broccoli 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 23 | Jun 23 – Aug 4 |
| Fall Sowing | August 4 | Aug 4 – Aug 18 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Marshall County
Growing Tips for Marshall County
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
Check more plant combinations with our Companion Planting Checker →
Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.
Broccoli in Other Locations
Frequently Asked Questions
When should I plant Broccoli in Marshall County, IL?
Marshall County is in Zone 5b with an average last frost of April 21. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marshall County, IL?
Marshall County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.
When should I plant Broccoli in Marshall County, IL?
In Marshall County, IL, plant Broccoli after the last frost (around April 21) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Marshall County, IL for Broccoli?
Marshall County sits in USDA Zone 5b. Broccoli grows reliably in zones 2a through 11b, so it's a good fit here.
Can Broccoli grow in Marshall County's climate?
Yes — Broccoli grows well in Marshall County's temperate climate. Marshall County averages a 175-day frost-free season, with last frost around April 21 and first frost around October 13.
Your Marshall County Garden Planner — Free
A 22-page printable planner built for Marshall County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.