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When to plant Bachelor's Button in Douglas County County,

For Douglas County County, gardeners: plant Bachelor's Button April 19 through May 10 once soil reads 50°F.

When to Plant Bachelor's Button in Douglas County, MN

Douglas County, Minnesota Zone 4b June

June in the garden — Douglas County, Minnesota

We've pulled the most time-sensitive tasks for Douglas County, Minnesota this June and put them front and centre. Tackle them in order.

Avg. last frost May 3
Avg. first frost October 4
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.5 hrs
  1. Start bachelor's button under lights

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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.

Douglas County, Minnesota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 4, giving you a growing season of approximately 154 days.

At an elevation of 1,010 feet, Douglas County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Bachelor's Button to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Douglas County, MN (Zone 4b) Moderate season
154 days
Last Spring Frost May 3
154 growing days
First Fall Frost October 4
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Douglas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Mar 8 Transplant: Apr 26 🌸 Bloom: Jun 28 – Aug 30
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 15 Transplant: May 3 🌸 Bloom: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (26 days to spare)
Start indoors: Mar 28 Transplant: May 16 🌸 Bloom: Jul 18 – Sep 19

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 Douglas County

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

Soil pH

Your soil pH (5.8–6.9) overlaps with Bachelor's Button's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Douglas 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

Succession Planting Bachelor's Button

2
successive plantings in your 154-day season

Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.

Bachelor's Button Water Budget

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

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 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 5.2" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Douglas 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 1,655 GDD Excellent fit

Bachelor's Button Planting Timeline — Douglas County, MN

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 3 May 3 – May 17
Direct Sow April 19 Apr 19 – May 10
Bloom July 5 Jul 5 – Sep 6

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

154 days in Douglas County

Growing Tips for Bachelor's Button in Douglas County

Direct sow Bachelor's Button outdoors after May 03 in Douglas 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 Douglas County, MN?

Douglas County is in Zone 4b with an average last frost of May 3. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, MN?

Douglas County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 4.

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

In Douglas County County, , plant Bachelor's Button after the last frost (around May 3) and before the first frost (around October 4). Best results when soil holds above 50°F.

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

Douglas County County sits in USDA Zone 4b. Bachelor's Button grows reliably in zones 2a through 11b, so it's a good fit here.

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

Yes — Bachelor's Button grows well in Douglas County County's temperate climate. Douglas County County averages a 154-day frost-free season, with last frost around May 3 and first frost around October 4.

🌱

Your Douglas County Garden Planner — Free

A 22-page printable planner built for Douglas County (Zone 4b). 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 Douglas County, MN. 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.