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When to Plant Bachelor's Button in Carroll County, NH

Carroll County, New Hampshire Zone 5a June

Your June game plan for Carroll County, New Hampshire

Your garden in Carroll County, New Hampshire is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost May 9
Avg. first frost October 6
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.3 hrs
  1. Fire up the seed-starting tray: bachelor's button

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Get ahead of July
  • 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.

Carroll County, New Hampshire is in USDA Zone 5a. The average last spring frost is May 9 and the first fall frost is October 6, giving you a growing season of approximately 150 days.

At an elevation of 433 feet, Carroll County receives approximately 41.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°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
Carroll County, NH (Zone 5a) Moderate season
150 days
Last Spring Frost May 9
150 growing days
First Fall Frost October 6
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Carroll County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.5

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Mar 20 Transplant: May 1 🌸 Bloom: Jul 3 – Sep 11
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Mar 28 Transplant: May 9 🌸 Bloom: Jul 11 – Sep 19
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Apr 15 Transplant: May 27 🌸 Bloom: Jul 29 – Oct 7

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 Carroll County

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

Soil pH

Your soil pH (5.2–6.5) 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 Carroll County is excellent for Bachelor's Button — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Bachelor's Button.

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 150-day season

Sow every 6.9 weeks. Last sowing by Jul 08 to harvest before frost.

Bachelor's Button Water Budget

Plant needs
0.5″/week
Rainfall provides
1.2″/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 3.3" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 3.9" 0" ❄️ Dormant
May 2.2" 3.3" 0" ✅ Rainfall sufficient
Jun 2.2" 4.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4.3" 0" ✅ Rainfall sufficient
Aug 2.2" 3.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.7" 0" ✅ Rainfall sufficient
Oct 2.2" 3.3" 0" ✅ Rainfall sufficient
Nov 3.1" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Carroll 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 ~750 GDD — county provides 1,500 GDD Excellent fit

Bachelor's Button Planting Timeline — Carroll County, NH

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 9 May 9 – May 23
Direct Sow April 18 Apr 18 – May 9
Bloom July 11 Jul 11 – Sep 19

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors 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: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

150 days in Carroll County

Growing Tips for Bachelor's Button in Carroll County

Direct sow Bachelor's Button outdoors after May 09 in Carroll 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 Carroll County, NH?

Carroll County is in Zone 5a with an average last frost of May 9. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carroll County, NH?

Carroll County, New Hampshire is in USDA Hardiness Zone 5a. The average last spring frost is May 9 and first fall frost is October 6.

🌱

Your Carroll County Garden Planner — Free

A 22-page printable planner built for Carroll 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 Carroll County, NH. 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.