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When to Plant Bachelor's Button in Humboldt County, NV

Humboldt County, Nevada Zone 6b June

June in the garden — Humboldt County, Nevada

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

Avg. last frost May 30
Avg. first frost September 15
Soil temp (4") 53°F
Watering Critical
Pest pressure High
Daylight 14.9 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.

Humboldt County, Nevada is in USDA Zone 6b. The average last spring frost is May 30 and the first fall frost is September 15, giving you a growing season of approximately 108 days.

At an elevation of 5,527 feet, Humboldt County receives approximately 8.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Bachelor's Button during the growing season. Sandy soil warms quickly in spring — great for early planting — but Bachelor's Button will need more frequent watering and organic matter to retain nutrients. 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
Humboldt County, NV (Zone 6b) Short season
108 days
Last Spring Frost May 30
108 growing days
First Fall Frost September 15

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.6

Drainage

Well Drained

Bachelor's Button Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 10 Transplant: May 22 🌸 Bloom: Jul 24 – Oct 16
Recommended (50%) ✗ May not fit
Start indoors: Apr 18 Transplant: May 30 🌸 Bloom: Aug 1 – Oct 24
Safe Start (90%) ✗ May not fit
Start indoors: May 7 Transplant: Jun 18 🌸 Bloom: Aug 20 – Nov 12

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 Humboldt County

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

Soil pH

Your soil pH (7.2–8.6) is more alkaline than Bachelor's Button prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Humboldt County warms quickly in spring but drains fast. Bachelor's Button will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Bachelor's Button.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting 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

2
successive plantings in your 108-day season

Sow every 6.9 weeks. Last sowing by Jun 17 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Bachelor's Button Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 382 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 0.6" 0" ❄️ Dormant
Feb 0.5" 0" ❄️ Dormant
Mar 0.4" 0" ❄️ Dormant
Apr 0.3" 0" ❄️ Dormant
May 2.2" 0.2" 2" 🚿 Regular watering
Jun 2.2" 0.3" 1.9" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.6" 0.6" 💧 Light watering
Sep 2.2" 1.1" 1.1" 🚿 Regular watering
Oct 0.8" 0" ❄️ Dormant
Nov 0.4" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Humboldt 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 ~1,538 GDD — county provides 2,214 GDD Excellent fit

Bachelor's Button Planting Timeline — Humboldt County, NV

Bachelor's Button Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 – May 2
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 2 May 2 – May 23
Bloom August 1 Aug 1 – Oct 24
Fall Sowing August 4 Aug 4 – Aug 18

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 Fall Sowing Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

108 days in Humboldt County

Growing Tips for Bachelor's Button in Humboldt County

Direct sow Bachelor's Button outdoors after May 30 in Humboldt County when soil has warmed and frost danger has passed.

Sandy soil in Humboldt County dries quickly — mulch Bachelor's Button with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Bachelor's Button in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Humboldt County receives only 8" 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 Humboldt County, NV?

Humboldt County is in Zone 6b with an average last frost of May 30. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.

What planting zone is Humboldt County, NV?

Humboldt County, Nevada is in USDA Hardiness Zone 6b. The average last spring frost is May 30 and first fall frost is September 15.

🌱

Your Humboldt County Garden Planner — Free

A 22-page printable planner built for Humboldt 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 Humboldt County, NV. 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.