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When to Plant Bachelor's Button in Harmon County, OK

Harmon County, Oklahoma Zone 7b June

Harmon County, Oklahoma gardeners: here's your June plan

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

Avg. last frost March 31
Avg. first frost November 5
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
  1. It's harvest week for bachelor's button

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

To set up a strong July, finish these tasks
  • 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.

Harmon County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 5, giving you a growing season of approximately 219 days.

At an elevation of 993 feet, Harmon County receives approximately 34.4 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Bachelor's Button during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Harmon County, OK (Zone 7b) Long season
219 days
Last Spring Frost March 31
219 growing days
First Fall Frost November 5
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Harmon County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Feb 9 Transplant: Mar 23 🌸 Bloom: May 25 – Aug 31
Recommended (50%) ✓ Fits season (58 days to spare)
Start indoors: Feb 17 Transplant: Mar 31 🌸 Bloom: Jun 2 – Sep 8
Safe Start (90%) ✓ Fits season (58 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🌸 Bloom: Jun 17 – Sep 23

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 Harmon County

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

Soil pH

Your soil pH (6.5–7.5) is within Bachelor's Button's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Bachelor's Button will thrive.

How to Plant Bachelor's Button

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Bachelor's Button

4
successive plantings in your 219-day season

Sow every 6.9 weeks. Last sowing by Aug 07 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
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 0.9" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 2.3" 0" ✅ Rainfall sufficient
Apr 2.2" 3.7" 0" ✅ Rainfall sufficient
May 2.2" 5.1" 0" ✅ Rainfall sufficient
Jun 2.2" 5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4.8" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 2" 0.2" 💧 Light watering
Nov 2.2" 1.3" 0.9" 💧 Light watering
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Harmon 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 ~1,369 GDD — county provides 3,996 GDD Excellent fit

Bachelor's Button Planting Timeline — Harmon County, OK

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors March 31 Mar 31 – Apr 14
Direct Sow February 24 Feb 24 – Mar 17
Bloom June 2 Jun 2 – Sep 8
Fall Sowing September 10 Sep 10 – Sep 24

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors Direct Sow
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors
May
June Bloom
July Bloom
August Bloom
September Fall Sowing Bloom
October
November
December
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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 7b

📆 Growing Season

219 days in Harmon County

Growing Tips for Bachelor's Button in Harmon County

Direct sow Bachelor's Button outdoors after March 31 in Harmon 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 Harmon County, OK?

Harmon County is in Zone 7b with an average last frost of March 31. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harmon County, OK?

Harmon County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 5.

🌱

Your Harmon County Garden Planner — Free

A 22-page printable planner built for Harmon County (Zone 7b). 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 Harmon County, OK. 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.