When to Plant Broccoli in USDA Zone 4b
This month in Zone 4b
Each item below is timed to Zone 4b's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Outdoor sowing time: broccoli
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
Looking ahead to May
- Transplants going out: broccoli
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.
In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.
Broccoli Planting Timeline — Zone 4b
Where Is USDA Zone 4b?
The map below highlights the states that contain Zone 4b. Click any state to see the Broccoli planting schedule for that location.
Broccoli Planting Calendar — Zone 4b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 20 | Mar 20 – Apr 3 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Direct Sow | April 24 | Apr 24 – May 15 |
| Harvest | July 3 | Jul 3 – Aug 14 |
| Fall Sowing | July 11 | Jul 11 – Jul 25 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Free Zone 4b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Moderate — regular watering
Days to Maturity
60–90 days
Soil pH
6 – 7
Zone Temperature Range
°F to °F average annual minimum
Growing Season
155 days (Zone average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 15 inches apart |
| Row Spacing | 24 inches between rows |
Succession Planting Broccoli in Zone
Sow every 6.9 weeks for continuous harvest throughout the season.
Growing Tips for Broccoli in Zone
Zone has a short growing season (~155 days). Start Broccoli indoors early and use season-extension techniques like row covers and cold frames.
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
The Gardener's Encyclopedia to Companion Planting
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Saving Broccoli Seeds
Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Broccoli in Other Zones
Broccoli by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Broccoli in Zone 4b?
In Zone 4b, plan your Broccoli planting around the average last frost date of May 1. Start seeds indoors around March 20. Direct sow outdoors around April 24. Transplant seedlings around May 1.
Can Broccoli grow in Zone 4b?
Yes, Broccoli can grow well in Zone 4b, hardy in USDA zones 2a through 11b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Broccoli (60-90 days to maturity).
When can I harvest Broccoli in Zone 4b?
In Zone 4b, expect to harvest Broccoli from July 3 – August 14. Broccoli takes 60-90 days from planting to harvest.
What is the last frost date for Zone 4b?
The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Broccoli?
Good companion plants for Broccoli include Celery, Onion, Potatoes, Dill. These companions can help with pest control, pollination, and nutrient sharing.
Your Free Printable Garden Planner
A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.