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When to Plant Broccoli in USDA Zone 5b

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 5b, the average last spring frost is around April 18 and the first fall frost is around October 13, giving you a growing season of approximately 178 days.

Zone 5b Moderate season
178 days
Last Spring Frost April 18
178 growing days
First Fall Frost October 13

Broccoli Planting Timeline — Zone 5b

Where Is USDA Zone 5b?

The map below highlights the states that contain Zone 5b. Click any state to see the Broccoli planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Broccoli Planting Calendar — Zone 5b

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 4 Apr 4 – Apr 25
Harvest June 20 Jun 20 – Aug 1
Fall Sowing August 4 Aug 4 – Aug 18

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 Harvest
September
October
November
December

Free Zone 5b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 5b with start dates, transplant windows, and harvest times.

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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

-15°F to -10°F average annual minimum

Growing Season

178 days (Zone 5b average)

Planting Specifications

Planting Depth1 inches
Plant Spacing15 inches apart
Row Spacing24 inches between rows

Succession Planting Broccoli in Zone 5b

3
successive plantings in Zone 5b's ~178-day season

Sow every 6.9 weeks for continuous harvest throughout the season.

Growing Tips for Broccoli in Zone 5b

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

Level Up Your Garden

Saving Broccoli Seeds

🌾 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.

Recommended for Your Garden

🌱
Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

🏷️
Garden Plant Markers $6-12

Keep your garden organized with durable, weather-resistant plant labels.

Related Plants

Frequently Asked Questions

When should I plant Broccoli in Zone 5b?

In Zone 5b, plan your Broccoli planting around the average last frost date of April 18. Start seeds indoors around March 14. Direct sow outdoors around April 4. Transplant seedlings around April 18.

Can Broccoli grow in Zone 5b?

Yes, Broccoli can grow well in Zone 5b, hardy in USDA zones 2a through 11b. Zone 5b has a growing season of approximately 178 days, which is sufficient for Broccoli (60-90 days to maturity).

When can I harvest Broccoli in Zone 5b?

In Zone 5b, expect to harvest Broccoli from June 20 – August 1. Broccoli takes 60-90 days from planting to harvest.

What is the last frost date for Zone 5b?

The average last spring frost in Zone 5b is around April 18, and the first fall frost is around October 13. This gives a growing season of approximately 178 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.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 5b, track your crops, and plan your garden season from seed to harvest.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.