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When to plant Geraniums in Mohawk, MI

In Mohawk, Geraniums is a spring-only crop. Plant May 26–June 9 once soil hits 50°F.

When to Plant Geraniums in Mohawk, MI

Keweenaw County, Michigan Zone 5b June

This month in Keweenaw County, Michigan

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

Avg. last frost May 19
Avg. first frost October 1
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.7 hrs
Looking ahead to July
  • Starting indoors: geraniums

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Geraniums (Pelargonium × hortorum) are tender perennials grown as warm-season annuals throughout North America. Prized for their bold flower clusters, long bloom period, and tolerance of summer heat when planted in well-drained soil, they anchor window boxes, containers, and bed borders from late spring until hard frost. Zones 9b–11b can overwinter plants in the ground.

Mohawk, Michigan is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,035 feet, Keweenaw County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Geraniums to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Mohawk, MI (Zone 5b) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1

Mohawk Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 6 Transplant: May 22 🌸 Bloom: Jul 31 – Oct 23
Recommended (50%) ✗ May not fit
Start indoors: Mar 10 Transplant: May 26 🌸 Bloom: Aug 4 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: Mar 26 Transplant: Jun 11 🌸 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 Mohawk

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

Soil pH

Your soil pH (6.1–6.9) is within Geraniums's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Geraniums will thrive.

How to Plant Geraniums

0.1"
Planting Depth
12"
Between Plants
14"
Between Rows

Succession Planting Geraniums

2
successive plantings in your 135-day season

Sow every 8 weeks. Last sowing by Jun 23 to harvest before frost.

Geraniums Water Budget

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

Monthly Watering Guide for Geraniums

Geraniums needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Geraniums Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Geraniums 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.

Geraniums needs ~914 GDD — county provides 1,451 GDD Excellent fit

Geraniums Planting Timeline — Mohawk, MI

Geraniums Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors May 26 May 26 – Jun 9
Bloom August 4 Aug 4 – Oct 27

Plant 0.1" deep · 12" apart · Rows 14" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

135 days in Keweenaw County

Growing Tips for Geraniums in Mohawk

Direct sow Geraniums outdoors after May 19 in Keweenaw County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 10–12 weeks before last frost — germination is slow and erratic without bottom heat (70–75°F). Transplant after frost danger passes. Geraniums rarely direct-sown; cuttings or transplants are the standard. Deadhead spent umbels weekly to maintain continuous bloom. Let soil dry slightly between waterings to prevent root rot. In zones 10–11 plants may be left in ground year-round or overwintered as houseplants.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Geraniums in Mohawk, MI?

In Mohawk, MI, plant Geraniums after the last frost (around May 19) and before the first frost (around October 1). Best results when soil holds above 50°F.

What growing zone is Mohawk, MI for Geraniums?

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

Can Geraniums grow in Mohawk's climate?

Yes — Geraniums grows well in Mohawk's temperate climate. Mohawk averages a 135-day frost-free season, with last frost around May 19 and first frost around October 1.

🌱

Your Keweenaw County Garden Planner — Free

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