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When to plant Bachelor's Button in Johnson County County,

In Zone 6a (Johnson County County), direct-sow Bachelor's Button between March 15 and April 5 for spring, after the April 12 last-frost mark. A second sowing from September 10 to September 24 extends the harvest into fall.

When to Plant Bachelor's Button in Johnson County, IN

Johnson County, Indiana Zone 6a June

Your June planting checklist for Johnson County, Indiana

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 April 12
Avg. first frost October 22
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. It's harvest week for bachelor's button

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Looking ahead to July
  • First harvests: bachelor's button

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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.

Johnson County, Indiana is in USDA Zone 6a. The average last spring frost is April 12 and the first fall frost is October 22, giving you a growing season of approximately 193 days.

At an elevation of 1,324 feet, Johnson County receives approximately 36.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Bachelor's Button during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Johnson County, IN (Zone 6a) Moderate season
193 days
Last Spring Frost April 12
193 growing days
First Fall Frost October 22

Johnson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (53 days to spare)
Start indoors: Feb 24 Transplant: Apr 7 🌸 Bloom: Jun 9 – Aug 25
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Mar 1 Transplant: Apr 12 🌸 Bloom: Jun 14 – Aug 30
Safe Start (90%) ✓ Fits season (47 days to spare)
Start indoors: Mar 18 Transplant: Apr 29 🌸 Bloom: Jul 1 – Sep 16

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 Johnson County

How your county's soil matches Bachelor's Button's growing requirements.

Soil pH

Your soil pH (6.2–7.0) is within Bachelor's Button's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Johnson County is excellent for Bachelor's Button — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Bachelor's Button will thrive.

How to Plant Bachelor's Button

0.3"
Planting Depth
12"
Between Plants
12"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Bachelor's Button

3
successive plantings in your 193-day season

Sow every 6.9 weeks. Last sowing by Jul 24 to harvest before frost.

For a dedicated fall crop, sow by Sep 10.

Bachelor's Button Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Bachelor's Button

Bachelor's Button needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Bachelor's Button Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 4.6" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 4.4" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Bachelor's Button 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.

Bachelor's Button needs ~1,312 GDD — county provides 3,377 GDD Excellent fit

Bachelor's Button Planting Timeline — Johnson County, IN

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors April 12 Apr 12 – Apr 26
Direct Sow March 15 Mar 15 – Apr 5
Bloom June 14 Jun 14 – Aug 30
Fall Sowing September 10 Sep 10 – Sep 24

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
June Bloom
July Bloom
August Bloom
September Fall Sowing
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

193 days in Johnson County

Growing Tips for Bachelor's Button in Johnson County

Direct sow Bachelor's Button outdoors after April 12 in Johnson County when soil has warmed and frost danger has passed.

Common pests for Bachelor's Button in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bachelor's Button in Johnson County, IN?

Johnson County is in Zone 6a with an average last frost of April 12. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnson County, IN?

Johnson County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 12 and first fall frost is October 22.

When should I plant Bachelor's Button in Johnson County County, ?

In Johnson County County, , plant Bachelor's Button after the last frost (around April 12) and before the first frost (around October 22). Best results when soil holds above 50°F.

What growing zone is Johnson County County, for Bachelor's Button?

Johnson County County sits in USDA Zone 6a. Bachelor's Button grows reliably in zones 2a through 11b, so it's a good fit here.

Can Bachelor's Button grow in Johnson County County's climate?

Yes — Bachelor's Button grows well in Johnson County County's temperate climate. Johnson County County averages a 193-day frost-free season, with last frost around April 12 and first frost around October 22.

🌱

Your Johnson County Garden Planner — Free

A 22-page printable planner built for Johnson County (Zone 6a). 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 Johnson County, IN. 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.