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When to plant Geraniums in Dickinson County County,

Dickinson County County's 159-day season only supports one Geraniums planting per year. Sow between May 7 and May 21 for the best chance at full maturity before October 6.

When to Plant Geraniums in Dickinson County, IA

Dickinson County, Iowa Zone 5a June

June in Dickinson County, Iowa — your action list

Welcome to June in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 30
Avg. first frost October 6
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
Coming up in July — start thinking about
  • Starting indoors: geraniums
  • First harvests: 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.

Dickinson County, Iowa is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 6, giving you a growing season of approximately 159 days.

At an elevation of 1,311 feet, Dickinson County receives approximately 33.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°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
Dickinson County, IA (Zone 5a) Moderate season
159 days
Last Spring Frost April 30
159 growing days
First Fall Frost October 6

Dickinson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Feb 11 Transplant: Apr 29 🌸 Bloom: Jul 8 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Feb 19 Transplant: May 7 🌸 Bloom: Jul 16 – Oct 8
Safe Start (90%) ✗ May not fit
Start indoors: Mar 5 Transplant: May 21 🌸 Bloom: Jul 30 – Oct 22

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 Dickinson County

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

Soil pH

Your soil pH (5.7–7.0) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — 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 159-day season

Sow every 8 weeks. Last sowing by Jun 28 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 209 gal / 100 sq ft
Drought risk

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

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 1.2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 3.3" 1" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Dickinson 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 ~1,105 GDD — county provides 2,067 GDD Excellent fit

Geraniums Planting Timeline — Dickinson County, IA

Geraniums Planting Calendar

Activity When Date Range
Start Indoors February 19 Feb 19 – Mar 5
Transplant Outdoors May 7 May 7 – May 21
Bloom July 16 Jul 16 – Oct 8

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

159 days in Dickinson County

Growing Tips for Geraniums in Dickinson County

Direct sow Geraniums outdoors after April 30 in Dickinson 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 →

Frequently Asked Questions

When should I plant Geraniums in Dickinson County, IA?

Dickinson County is in Zone 5a with an average last frost of April 30. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dickinson County, IA?

Dickinson County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 6.

When should I plant Geraniums in Dickinson County County, ?

In Dickinson County County, , plant Geraniums after the last frost (around April 30) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Dickinson County County, for Geraniums?

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

Can Geraniums grow in Dickinson County County's climate?

Yes — Geraniums grows well in Dickinson County County's temperate climate. Dickinson County County averages a 159-day frost-free season, with last frost around April 30 and first frost around October 6.

🌱

Your Dickinson County Garden Planner — Free

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

Sources & credits

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