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When to plant Geraniums in Roxana, IL

Roxana's 194-day season only supports one Geraniums planting per year. Sow between April 11 and April 25 for the best chance at full maturity before October 22.

When to Plant Geraniums in Roxana, IL

Madison County, Illinois Zone 7a June

Your June planting checklist for Madison County, Illinois

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

Avg. last frost April 11
Avg. first frost October 22
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Begin indoor sowing: geraniums

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Start harvesting geraniums

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

July prep starts now
  • 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.

Roxana, Illinois is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 22, giving you a growing season of approximately 194 days.

At an elevation of 963 feet, Madison County receives approximately 36.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Geraniums during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Roxana, IL (Zone 7a) Moderate season
194 days
Last Spring Frost April 11
194 growing days
First Fall Frost October 22

Roxana Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (14 days to spare)
Start indoors: Jan 24 Transplant: Apr 4 🌸 Bloom: Jun 13 – Oct 3
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Jan 31 Transplant: Apr 11 🌸 Bloom: Jun 20 – Oct 10
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Feb 9 Transplant: Apr 20 🌸 Bloom: Jun 29 – Oct 19

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 Roxana

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

Soil pH

Your soil pH (5.8–6.9) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Madison 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

3
successive plantings in your 194-day season

Sow every 8 weeks. Last sowing by Jul 14 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 421 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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Madison 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 ~1,424 GDD — county provides 3,249 GDD Excellent fit

Geraniums Planting Timeline — Roxana, IL

Geraniums Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 11 Apr 11 – Apr 25
Bloom June 20 Jun 20 – Oct 10

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 · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

194 days in Madison County

Growing Tips for Geraniums in Roxana

Direct sow Geraniums outdoors after April 11 in Madison 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 Roxana, IL?

In Roxana, IL, plant Geraniums after the last frost (around April 11) and before the first frost (around October 22). Best results when soil holds above 50°F.

What growing zone is Roxana, IL for Geraniums?

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

Can Geraniums grow in Roxana's climate?

Yes — Geraniums grows well in Roxana's temperate climate. Roxana averages a 194-day frost-free season, with last frost around April 11 and first frost around October 22.

🌱

Your Madison County Garden Planner — Free

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