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When to plant Bachelor's Button in Benton County, MO

Benton County's spring Bachelor's Button window runs March 12 through April 2. time plantings around the expected last-frost window for best survival. A second sowing from September 13 to September 27 extends the harvest into fall.

When to Plant Bachelor's Button in Benton County, MO

Benton County, Missouri Zone 6b June

Benton County, Missouri gardeners: here's your June plan

Here's what deserves your attention in Benton County, Missouri this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 9
Avg. first frost October 25
Soil temp (4") 71°F
Watering Low
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.

Benton County, Missouri is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 25, giving you a growing season of approximately 199 days.

At an elevation of 1,323 feet, Benton County receives approximately 39.3 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
Benton County, MO (Zone 6b) Moderate season
199 days
Last Spring Frost April 9
199 growing days
First Fall Frost October 25

Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Feb 21 Transplant: Apr 4 🌸 Bloom: Jun 6 – Aug 29
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 26 Transplant: Apr 9 🌸 Bloom: Jun 11 – Sep 3
Safe Start (90%) ✓ Fits season (48 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🌸 Bloom: Jun 30 – Sep 22

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 Benton County

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

Soil pH

Your soil pH (5.3–6.6) is more acidic than Bachelor's Button prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Bachelor's Button prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Bachelor's Button.

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 199-day season

Sow every 6.9 weeks. Last sowing by Jul 27 to harvest before frost.

For a dedicated fall crop, sow by Sep 13.

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
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 1.5" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 2.2" 4.4" 0" ✅ Rainfall sufficient
May 2.2" 5.1" 0" ✅ Rainfall sufficient
Jun 2.2" 4.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 3.9" 0" ✅ Rainfall sufficient
Sep 2.2" 3.5" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Benton 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 3,482 GDD Excellent fit

Bachelor's Button Planting Timeline — Benton County, MO

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow March 12 Mar 12 – Apr 2
Bloom June 11 Jun 11 – Sep 3
Fall Sowing September 13 Sep 13 – Sep 27

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

199 days in Benton County

Growing Tips for Bachelor's Button in Benton County

Direct sow Bachelor's Button outdoors after April 09 in Benton 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 Benton County, MO?

Benton County is in Zone 6b with an average last frost of April 9. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benton County, MO?

Benton County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 25.

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

In Benton County, MO, plant Bachelor's Button after the last frost (around April 9) and before the first frost (around October 25). Best results when soil holds above 50°F.

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

Benton 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 Benton County's climate?

Yes — Bachelor's Button grows well in Benton County's temperate climate. Benton County averages a 199-day frost-free season, with last frost around April 9 and first frost around October 25.

🌱

Your Benton County Garden Planner — Free

A 22-page printable planner built for Benton 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 Benton County, MO. 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.