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

Plant Bachelor's Button in Ottawa County, when soil hits 50°F — usually March 17. Continue planting through April 7 for the spring crop. A second sowing from September 11 to September 25 extends the harvest into fall.

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

Ottawa County, Kansas Zone 6b June

This month in Ottawa County, Kansas

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

Avg. last frost April 14
Avg. first frost October 23
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.7 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.

Ottawa County, Kansas is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 23, giving you a growing season of approximately 192 days.

At an elevation of 993 feet, Ottawa County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Bachelor's Button during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Ottawa County, KS (Zone 6b) Moderate season
192 days
Last Spring Frost April 14
192 growing days
First Fall Frost October 23

Ottawa County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (39 days to spare)
Start indoors: Feb 28 Transplant: Apr 11 🌸 Bloom: Jun 13 – Sep 5
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 3 Transplant: Apr 14 🌸 Bloom: Jun 16 – Sep 8
Safe Start (90%) ✓ Fits season (42 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🌸 Bloom: Jun 29 – Sep 21

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 Ottawa County

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

Soil pH

Your soil pH (6.8–7.6) overlaps with Bachelor's Button's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 192-day season

Sow every 6.9 weeks. Last sowing by Jul 25 to harvest before frost.

For a dedicated fall crop, sow by Sep 11.

Bachelor's Button Water Budget

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

Water stress score is 6/10 — 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 0.7" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.2" 2.4" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 3.5" 0" ✅ Rainfall sufficient
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 2.9" 0" ✅ Rainfall sufficient
Sep 2.2" 2.3" 0" ✅ Rainfall sufficient
Oct 2.2" 1.7" 0.5" 💧 Light watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ottawa 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 ~1,031 GDD — county provides 2,640 GDD Excellent fit

Bachelor's Button Planting Timeline — Ottawa County, KS

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 17 Mar 17 – Apr 7
Bloom June 16 Jun 16 – Sep 8
Fall Sowing September 11 Sep 11 – Sep 25

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 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 6b

📆 Growing Season

192 days in Ottawa County

Growing Tips for Bachelor's Button in Ottawa County

Direct sow Bachelor's Button outdoors after April 14 in Ottawa 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.

Ottawa 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 Ottawa County, KS?

Ottawa County is in Zone 6b with an average last frost of April 14. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ottawa County, KS?

Ottawa County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 23.

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

In Ottawa County, KS, plant Bachelor's Button after the last frost (around April 14) and before the first frost (around October 23). Best results when soil holds above 50°F.

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

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

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

Yes — Bachelor's Button grows well in Ottawa County's temperate climate. Ottawa County averages a 192-day frost-free season, with last frost around April 14 and first frost around October 23.

🌱

Your Ottawa County Garden Planner — Free

A 22-page printable planner built for Ottawa County (Zone 6b). 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 Ottawa 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.