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When to plant Geraniums in Hardin County, IL

Plant Geraniums in Hardin County during the brief April 4–April 18 window. With 210 frost-free days, fall plantings can't mature before October 31.

When to Plant Geraniums in Hardin County, IL

Hardin County, Illinois Zone 7a June

June to-do list for Hardin County, Illinois

A quick June briefing for Hardin County, Illinois gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 4
Avg. first frost October 31
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
  1. Sow geraniums in trays indoors

    Label every cell. You will absolutely forget which is which otherwise.

  2. Start harvesting geraniums

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to July
  • 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.

Hardin County, Illinois is in USDA Zone 7a. The average last spring frost is April 4 and the first fall frost is October 31, giving you a growing season of approximately 210 days.

At an elevation of 1,218 feet, Hardin County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Geraniums during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Hardin County, IL (Zone 7a) Long season
210 days
Last Spring Frost April 4
210 growing days
First Fall Frost October 31

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Jan 17 Transplant: Mar 28 🌸 Bloom: Jun 6 – Sep 26
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Jan 24 Transplant: Apr 4 🌸 Bloom: Jun 13 – Oct 3
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Feb 6 Transplant: Apr 17 🌸 Bloom: Jun 26 – Oct 16

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 Hardin County

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

Soil pH

Your soil pH (6.2–7.2) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Geraniums will thrive.

How to Plant Geraniums

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

Succession Planting Geraniums

3
successive plantings in your 210-day season

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

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 740 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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 3.4" 0.9" 💧 Light watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hardin 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 ~1,360 GDD — county provides 3,360 GDD Excellent fit

Geraniums Planting Timeline — Hardin County, IL

Geraniums Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 – Feb 7
Transplant Outdoors April 4 Apr 4 – Apr 18
Bloom June 13 Jun 13 – Oct 3

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

210 days in Hardin County

Growing Tips for Geraniums in Hardin County

Direct sow Geraniums outdoors after April 04 in Hardin 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 Hardin County, IL?

Hardin County is in Zone 7a with an average last frost of April 4. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, IL?

Hardin County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 4 and first fall frost is October 31.

When should I plant Geraniums in Hardin County, IL?

In Hardin County, IL, plant Geraniums after the last frost (around April 4) and before the first frost (around October 31). Best results when soil holds above 50°F.

What growing zone is Hardin County, IL for Geraniums?

Hardin County sits in USDA Zone 7a. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.

Can Geraniums grow in Hardin County's climate?

Yes — Geraniums grows well in Hardin County's temperate climate. Hardin County averages a 210-day frost-free season, with last frost around April 4 and first frost around October 31.

🌱

Your Hardin County Garden Planner — Free

A 22-page printable planner built for Hardin County (Zone 7a). 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 Hardin County, IL. 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.