When to plant Bachelor's Button in Olmsted County, MN
In Olmsted County, plant Bachelor's Button in spring between April 19 and May 10, once soil temps hold above 50°F. Olmsted County's last frost averages May 3, so be cautious and check the 10-day forecast before planting tender crops. For a fall crop, sow between and — roughly 90 days before the first frost on October 4.
When to Plant Bachelor's Button in Olmsted County, MN
June to-do list for Olmsted County, Minnesota
A quick June briefing for Olmsted County, Minnesota gardeners — what's urgent, what's next, and what can wait.
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.
Olmsted 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 992 feet, Olmsted County receives approximately 32.8 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.
Olmsted County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.3
Drainage
Well Drained
Bachelor's Button Planting Risk Windows
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 Olmsted County
How your county's soil matches Bachelor's Button's growing requirements.
Soil pH
Your soil pH (5.9–7.3) overlaps with Bachelor's Button's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Olmsted County is excellent for Bachelor's Button — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Bachelor's Button.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Bachelor's Button.
How to Plant Bachelor's Button
Succession Planting Bachelor's Button
Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.
Bachelor's Button Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | — | 2.9" | 0" | ❄️ Dormant |
| May | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Olmsted 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 Planting Timeline — Olmsted 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
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
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 Olmsted County
Growing Tips for Bachelor's Button in Olmsted County
Direct sow Bachelor's Button outdoors after May 03 in Olmsted 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 →
Bachelor's Button in Other Locations
Frequently Asked Questions
When should I plant Bachelor's Button in Olmsted County, MN?
Olmsted 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 Olmsted County, MN?
Olmsted 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 Olmsted County, MN?
In Olmsted County, MN, 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 Olmsted County, MN for Bachelor's Button?
Olmsted 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 Olmsted County's climate?
Yes — Bachelor's Button grows well in Olmsted County's temperate climate. Olmsted County averages a 154-day frost-free season, with last frost around May 3 and first frost around October 4.
Your Olmsted County Garden Planner — Free
A 22-page printable planner built for Olmsted 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.