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When to plant Geraniums in Worth County, IA

In Worth County, Geraniums is a single-season spring crop — there's no second fall window. Plant May 7–May 21 for an 70–100-day harvest, finishing well before the October 7 first frost.

When to Plant Geraniums in Worth County, IA

Worth County, Iowa Zone 5a June

This month in Worth County, Iowa

Here's what deserves your attention in Worth County, Iowa this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
July will be here before you know it — start on
  • 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.

Worth County, Iowa is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 886 feet, Worth County receives approximately 39.8 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
Worth County, IA (Zone 5a) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7

Worth County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Feb 13 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 2
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 6 Transplant: May 22 🌸 Bloom: Jul 31 – Oct 23

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 Worth County

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

Soil pH

Your soil pH (6.0–7.3) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.9%) — 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 160-day season

Sow every 8 weeks. Last sowing by Jun 29 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/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 1.6" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Worth 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 2,080 GDD Excellent fit

Geraniums Planting Timeline — Worth 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 · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

160 days in Worth County

Growing Tips for Geraniums in Worth County

Direct sow Geraniums outdoors after April 30 in Worth 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 Worth County, IA?

Worth 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 Worth County, IA?

Worth County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 7.

When should I plant Geraniums in Worth County, IA?

In Worth County, IA, plant Geraniums after the last frost (around April 30) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Worth County, IA for Geraniums?

Worth 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 Worth County's climate?

Yes — Geraniums grows well in Worth County's temperate climate. Worth County averages a 160-day frost-free season, with last frost around April 30 and first frost around October 7.

🌱

Your Worth County Garden Planner — Free

A 22-page printable planner built for Worth 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 Worth 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.