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When to Plant Bachelor's Button in USDA Zone 5b

Zone 5b Zone 5b June

June to-do list for Zone 5b

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 1
Avg. first frost October 9
  1. Indoor seed-starting week for bachelor's button

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

A few tasks this June that'll pay off in July
  • First harvests: bachelor's button
Send me my free Zone 5b Planting Guide →

Bachelor's Button (Centaurea cyanus), also called cornflower, is a carefree cool-season annual best known for its vivid cobalt-blue flowers — one of the truest blues in the annual garden. It tolerates light frosts, self-seeds prolifically, and thrives in poor to average soils. A traditional cut flower and pollinator magnet, it has been cultivated in gardens for centuries.

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.

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

Bachelor's Button 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 Bachelor's Button planting schedule for that location.

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

Bachelor's Button Planting Calendar — Zone 5b

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow March 28 Mar 28 – Apr 18
Bloom June 20 Jun 20 – Sep 5

Plant 0.3" deep · 12" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Transplant Outdoors
June Bloom
July Bloom
August Bloom
September Bloom
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

Low — drought tolerant

Days to Maturity

60–90 days

Soil pH

6 – 7.5

Zone Temperature Range

-15°F to -10°F average annual minimum

Growing Season

178 days (Zone 5b average)

Planting Specifications

Planting Depth0.3 inches
Plant Spacing12 inches apart
Row Spacing12 inches between rows

Succession Planting Bachelor's Button 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 Bachelor's Button in Zone 5b

Direct-sow in early spring as soon as soil can be worked; seeds need a brief cold period for best germination (refrigerate for a few days before planting if spring arrives quickly). In zones 6+, fall-sow for the earliest spring bloom. Thin to 12 inches; do not over-fertilize — too much nitrogen produces foliage at the expense of flowers. Deadhead to prolong blooming or allow self-seeding for a naturalized colony.

Companion Planting

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Saving Bachelor's Button Seeds

Recommended for Your Garden

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Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

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Soil Test Kit $12-25

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

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

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Frequently Asked Questions

When should I plant Bachelor's Button in Zone 5b?

In Zone 5b, plan your Bachelor's Button planting around the average last frost date of April 18. Start seeds indoors around March 7. Direct sow outdoors around March 28. Transplant seedlings around April 18.

Can Bachelor's Button grow in Zone 5b?

Yes, Bachelor's Button 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 Bachelor's Button (60-90 days to maturity).

When can I harvest Bachelor's Button in Zone 5b?

In Zone 5b, expect to harvest Bachelor's Button from June 20 – September 5. Bachelor's Button 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 Bachelor's Button?

Good companion plants for Bachelor's Button include Wheat, Grains, Tomatoes, Vegetables. These companions can help with pest control, pollination, and nutrient sharing.

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Your Zone 5b Garden Planner — Free

A 22-page printable planner tailored to Zone 5b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.

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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: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.