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When to plant Calendula in Alcona County, MI

Alcona County sits in cold Zone 5b. Plant Calendula April 26–May 17 for the single annual harvest; the October 3 first frost closes the window.

When to Plant Calendula in Alcona County, MI

Alcona County, Michigan Zone 5b June

Your June gardening checklist

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Alcona County, Michigan.

Avg. last frost May 17
Avg. first frost October 3
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 15.4 hrs
  1. Get calendula seeds going inside

    You're about 14 weeks out from your last frost — the perfect window to get these germinating indoors.

Before July arrives, get these ready
  • First harvests: calendula

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Calendula (Calendula officinalis) is a cheerful, edible-flowered cool-season annual valued by herbalists, chefs, and gardeners alike. Its golden-orange petals are used in salves, teas, and as a saffron substitute. Hardy enough to tolerate light frosts, it blooms prolifically in spring and fall, taking a pause during the hottest weeks of summer.

Alcona County, Michigan is in USDA Zone 5b. The average last spring frost is May 17 and the first fall frost is October 3, giving you a growing season of approximately 139 days.

At an elevation of 1,061 feet, Alcona County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Calendula during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Alcona County, MI (Zone 5b) Short season
139 days
Last Spring Frost May 17
139 growing days
First Fall Frost October 3

Alcona County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 29 Transplant: May 10 🌸 Bloom: Jun 28 – Sep 27
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 17 🌸 Bloom: Jul 5 – Oct 4
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Apr 16 Transplant: May 28 🌸 Bloom: Jul 16 – Oct 15

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 Alcona County

How your county's soil matches Calendula's growing requirements.

Soil pH

Your soil pH (6.1–7.2) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Alcona County is excellent for Calendula — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) — Calendula will thrive.

How to Plant Calendula

0.3"
Planting Depth
9"
Between Plants
12"
Between Rows

Succession Planting Calendula

3
successive plantings in your 139-day season

Sow every 5.7 weeks. Last sowing by Jul 25 to harvest before frost.

Calendula Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Calendula

Calendula 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 Calendula Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 4" 0" ❄️ Dormant
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.4" 0" ✅ Rainfall sufficient
Jul 2.2" 4.8" 0" ✅ Rainfall sufficient
Aug 2.2" 4.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Alcona County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Calendula 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.

Calendula needs ~870 GDD — county provides 2,015 GDD Excellent fit

Calendula Planting Timeline — Alcona County, MI

Calendula Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 17 May 17 – May 31
Direct Sow April 26 Apr 26 – May 17
Bloom July 5 Jul 5 – Oct 4

Plant 0.3" deep · 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

139 days in Alcona County

Growing Tips for Calendula in Alcona County

Direct sow Calendula outdoors after May 17 in Alcona County when soil has warmed and frost danger has passed.

Common pests for Calendula 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 germinate in cool soil (50-65°F). In zones 7+, also sow in fall for winter/spring bloom. Deadhead consistently to extend bloom. Plants self-seed readily; save a few spent heads and allow them to drop. Harvest petals when flowers are fully open for best flavor and medicinal value.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Calendula in Alcona County, MI?

Alcona County is in Zone 5b with an average last frost of May 17. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Alcona County, MI?

Alcona County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 17 and first fall frost is October 3.

When should I plant Calendula in Alcona County, MI?

In Alcona County, MI, plant Calendula after the last frost (around May 17) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Alcona County, MI for Calendula?

Alcona County sits in USDA Zone 5b. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.

Can Calendula grow in Alcona County's climate?

Yes — Calendula grows well in Alcona County's temperate climate. Alcona County averages a 139-day frost-free season, with last frost around May 17 and first frost around October 3.

🌱

Your Alcona County Garden Planner — Free

A 22-page printable planner built for Alcona County (Zone 5b). 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 Alcona County, MI. 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.