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When to Plant Bachelor's Button in Rich County, UT

Rich County, Utah Zone 5a June

June to-do list for Rich County, Utah

Each item below is timed to Rich County, Utah's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 31
Avg. first frost September 15
Soil temp (4") 50°F
Watering High
Pest pressure High
Daylight 15 hrs
Looking ahead to July
  • Starting indoors: 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.

Rich County, Utah is in USDA Zone 5a. The average last spring frost is May 31 and the first fall frost is September 15, giving you a growing season of approximately 107 days.

At an elevation of 5,803 feet, Rich County receives approximately 18 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Bachelor's Button to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Bachelor's Button successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Rich County, UT (Zone 5a) Short season
107 days
Last Spring Frost May 31
107 growing days
First Fall Frost September 15
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Rich County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.2

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: May 14 🌸 Bloom: Jul 16 – Sep 24
Recommended (50%) ✗ May not fit
Start indoors: Apr 19 Transplant: May 31 🌸 Bloom: Aug 2 – Oct 11
Safe Start (90%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 22 🌸 Bloom: Aug 24 – Nov 2

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 Rich County

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

Soil pH

Your soil pH (6.5–8.2) overlaps with Bachelor's Button's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Bachelor's Button.

How to Plant Bachelor's Button

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

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 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 1.3" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.2" 1.9" 0.3" 💧 Light watering
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 1.7" 0.5" 💧 Light watering
Aug 2.2" 1.7" 0.5" 💧 Light watering
Sep 2.2" 1.4" 0.8" 💧 Light watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Rich 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 ~806 GDD — county provides 1,150 GDD Excellent fit

Bachelor's Button Planting Timeline — Rich County, UT

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors April 19 Apr 19 – May 3
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 10 May 10 – May 31
Bloom August 2 Aug 2 – Oct 11

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors
July
August Bloom
September Bloom
October Bloom
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: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

107 days in Rich County

Growing Tips for Bachelor's Button in Rich County

Direct sow Bachelor's Button outdoors after May 31 in Rich 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.

Rich County receives only 18" 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 Rich County, UT?

Rich County is in Zone 5a with an average last frost of May 31. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rich County, UT?

Rich County, Utah is in USDA Hardiness Zone 5a. The average last spring frost is May 31 and first fall frost is September 15.

🌱

Your Rich County Garden Planner — Free

A 22-page printable planner built for Rich County (Zone 5a). 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 Rich County, UT. 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.