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When to plant Cosmos in Shingleton, MI

Aim to plant Cosmos in Shingleton on or after May 17; the window stays open through June 7. Shingleton's 159-day frost-free season gives you a single solid spring crop with a brief fall option.

When to Plant Cosmos in Shingleton, MI

Alger County, Michigan Zone 5a June

This month in Alger County, Michigan

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

Avg. last frost May 10
Avg. first frost October 16
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.6 hrs
  1. Start cosmos indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

A few tasks this June that'll pay off in July
  • First harvests: cosmos

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Cosmos (Cosmos bipinnatus) is an airy, feathery-foliaged cottage garden annual from Mexico that thrives on neglect. It produces delicate daisy-like blooms in shades of pink, white, and magenta from midsummer until frost. Cosmos is a prolific self-sower — once established in a garden it often returns year after year without replanting. Excellent habitat plant for beneficial insects.

Shingleton, Michigan is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 16, giving you a growing season of approximately 159 days.

At an elevation of 1,014 feet, Alger County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Cosmos to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Shingleton, MI (Zone 5a) Moderate season
159 days
Last Spring Frost May 10
159 growing days
First Fall Frost October 16

Shingleton Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.1

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 4 Transplant: May 9 🌸 Bloom: Jul 18 – Oct 10
Recommended (50%) ✗ May not fit
Start indoors: Apr 12 Transplant: May 17 🌸 Bloom: Jul 26 – Oct 18
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: Apr 27 Transplant: Jun 1 🌸 Bloom: Aug 10 – Nov 2

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 Shingleton

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

Soil pH

Your soil pH (6.3–7.1) is within Cosmos's preferred range (6.0–8.0).

Soil Texture

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

Drainage

Drainage is adequate for Cosmos.

Organic Matter

Organic matter is excellent (4.8%) — Cosmos will thrive.

How to Plant Cosmos

0.3"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Cosmos

3
successive plantings in your 159-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

Cosmos Water Budget

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

Monthly Watering Guide for Cosmos

Cosmos 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 Cosmos Needs Rainfall You Supplement Action
Jan 2" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 5" 0" ✅ Rainfall sufficient
Jul 2.2" 5" 0" ✅ Rainfall sufficient
Aug 2.2" 4.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

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

Cosmos 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.

Cosmos needs ~750 GDD — county provides 1,590 GDD Excellent fit

Cosmos Planting Timeline — Shingleton, MI

Cosmos Planting Calendar

Activity When Date Range
Start Indoors April 12 Apr 12 – Apr 26
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 17 May 17 – Jun 7
Bloom July 26 Jul 26 – Oct 18

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Direct Sow
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

60–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

159 days in Alger County

Growing Tips for Cosmos in Shingleton

Direct sow Cosmos outdoors after May 10 in Alger County when soil has warmed and frost danger has passed.

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

General growing tips

Direct-sow after last frost; cosmos germinates readily at 65-80°F in 7-10 days. Avoid rich soil — excess fertility produces lush foliage at the expense of blooms. Cosmos tolerates poor, dry soil exceptionally well. Pinch seedlings at 8 inches to encourage branching. Self-sows freely; allow some seed heads to mature and drop for a no-fuss perennial effect in warm climates.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Cosmos in Shingleton, MI?

In Shingleton, MI, plant Cosmos after the last frost (around May 10) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Shingleton, MI for Cosmos?

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

Can Cosmos grow in Shingleton's climate?

Yes — Cosmos grows well in Shingleton's temperate climate. Shingleton averages a 159-day frost-free season, with last frost around May 10 and first frost around October 16.

🌱

Your Alger County Garden Planner — Free

A 22-page printable planner built for Alger 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 Alger County, MI. Local conditions may vary. Last updated: June 2026.