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When to plant Bachelor's Button in Hamilton County, KS

Plant Bachelor's Button in Hamilton County from March 30 to April 20 in spring. Hamilton County sits in USDA Zone 6a, with last frost around April 27 and first frost on October 12. A second sowing from August 31 to September 14 extends the harvest into fall.

When to Plant Bachelor's Button in Hamilton County, KS

Hamilton County, Kansas Zone 6a June

June in the garden — Hamilton County, Kansas

June is a pivotal month for Hamilton County, Kansas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 27
Avg. first frost October 12
Soil temp (4") 72°F
Watering High
Pest pressure High
Daylight 14.6 hrs

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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.

Hamilton County, Kansas is in USDA Zone 6a. The average last spring frost is April 27 and the first fall frost is October 12, giving you a growing season of approximately 168 days.

At an elevation of 871 feet, Hamilton County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Bachelor's Button during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Hamilton County, KS (Zone 6a) Moderate season
168 days
Last Spring Frost April 27
168 growing days
First Fall Frost October 12

Hamilton County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Mar 10 Transplant: Apr 21 🌸 Bloom: Jun 23 – Sep 8
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🌸 Bloom: Jun 29 – Sep 14
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Mar 31 Transplant: May 12 🌸 Bloom: Jul 14 – Sep 29

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 Hamilton County

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

Soil pH

Your soil pH (6.3–7.8) overlaps with Bachelor's Button's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 168-day season

Sow every 6.9 weeks. Last sowing by Jul 14 to harvest before frost.

For a dedicated fall crop, sow by Aug 31.

Bachelor's Button Water Budget

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

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.5" 0.7" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2.6" 0" ✅ Rainfall sufficient
Sep 2.2" 1.7" 0.5" 💧 Light watering
Oct 2.2" 2" 0.2" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hamilton 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 ~1,425 GDD — county provides 3,192 GDD Excellent fit

Bachelor's Button Planting Timeline — Hamilton County, KS

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow March 30 Mar 30 – Apr 20
Bloom June 29 Jun 29 – Sep 14
Fall Sowing August 31 Aug 31 – Sep 14

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 Fall Sowing Bloom
September Fall Sowing Bloom
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: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

168 days in Hamilton County

Growing Tips for Bachelor's Button in Hamilton County

Direct sow Bachelor's Button outdoors after April 27 in Hamilton 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.

Hamilton County receives only 24" of rain annually. Bachelor's Button needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Hamilton County, KS?

Hamilton County is in Zone 6a with an average last frost of April 27. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, KS?

Hamilton County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 27 and first fall frost is October 12.

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

In Hamilton County, KS, plant Bachelor's Button after the last frost (around April 27) and before the first frost (around October 12). Best results when soil holds above 50°F.

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

Hamilton 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 Hamilton County's climate?

Yes — Bachelor's Button grows well in Hamilton County's temperate climate. Hamilton County averages a 168-day frost-free season, with last frost around April 27 and first frost around October 12.

🌱

Your Hamilton County Garden Planner — Free

A 22-page printable planner built for Hamilton 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 Hamilton County, KS. 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.