Blog

When to plant Geraniums in Henry County County,

In Henry County County, Geraniums is a single-season spring crop — there's no second fall window. Plant April 28–May 12 for an 100-day harvest, finishing well before the October 14 first frost.

When to Plant Geraniums in Henry County, IA

Henry County, Iowa Zone 5b June

June in the garden — Henry County, Iowa

Each item below is timed to Henry County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 21
Avg. first frost October 14
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Begin indoor sowing: geraniums

    These need a head start before your last frost (April 21). Sow into cells now so you're ready to transplant in a few weeks.

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

Instant PDF download. No spam, unsubscribe any time.

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.

Henry County, Iowa is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 14, giving you a growing season of approximately 176 days.

At an elevation of 879 feet, Henry County receives approximately 40.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Geraniums during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Henry County, IA (Zone 5b) Moderate season
176 days
Last Spring Frost April 21
176 growing days
First Fall Frost October 14

Henry County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Feb 3 Transplant: Apr 21 🌸 Bloom: Jun 30 – Sep 22
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Feb 10 Transplant: Apr 28 🌸 Bloom: Jul 7 – Sep 29
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Feb 23 Transplant: May 11 🌸 Bloom: Jul 20 – Oct 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 Henry County

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

Soil pH

Your soil pH (5.8–7.2) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — 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 176-day season

Sow every 8 weeks. Last sowing by Jul 06 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 64 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 1.5" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 4.4" 0" ✅ Rainfall sufficient
May 4.3" 4.9" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Henry 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 ~1,232 GDD — county provides 2,552 GDD Excellent fit

Geraniums Planting Timeline — Henry County, IA

Geraniums Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors April 28 Apr 28 – May 12
Bloom July 7 Jul 7 – Sep 29

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors
May Transplant Outdoors
June
July Bloom
August Bloom
September Bloom
October
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 5b

📆 Growing Season

176 days in Henry County

Growing Tips for Geraniums in Henry County

Direct sow Geraniums outdoors after April 21 in Henry 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 Henry County, IA?

Henry County is in Zone 5b with an average last frost of April 21. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Henry County, IA?

Henry County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 14.

When should I plant Geraniums in Henry County County, ?

In Henry County County, , plant Geraniums after the last frost (around April 21) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Henry County County, for Geraniums?

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

Can Geraniums grow in Henry County County's climate?

Yes — Geraniums grows well in Henry County County's temperate climate. Henry County County averages a 176-day frost-free season, with last frost around April 21 and first frost around October 14.

🌱

Your Henry County Garden Planner — Free

A 22-page printable planner built for Henry 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Henry County, IA. 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.