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When to plant Geraniums in Mount Olive, IL

In Mount Olive, Geraniums is a single-season spring crop — there's no second fall window. Plant April 18–May 2 for an 100-day harvest, finishing well before the October 21 first frost.

When to Plant Geraniums in Mount Olive, IL

Macoupin County, Illinois Zone 6b June

Macoupin County, Illinois gardeners: here's your June plan

Your Macoupin County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 11
Avg. first frost October 21
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Indoor seed-starting week for geraniums

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Start harvesting geraniums

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

July will be here before you know it — start on
  • 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.

Mount Olive, Illinois is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 21, giving you a growing season of approximately 193 days.

At an elevation of 859 feet, Macoupin County receives approximately 30.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Geraniums during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Mount Olive, IL (Zone 6b) Moderate season
193 days
Last Spring Frost April 11
193 growing days
First Fall Frost October 21

Mount Olive Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (20 days to spare)
Start indoors: Jan 24 Transplant: Apr 11 🌸 Bloom: Jun 20 – Sep 26
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Jan 31 Transplant: Apr 18 🌸 Bloom: Jun 27 – Oct 3
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Feb 9 Transplant: Apr 27 🌸 Bloom: Jul 6 – 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 Mount Olive

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — 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 193-day season

Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 563 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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.7" 1.6" 💧 Light watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Macoupin 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 ~1,488 GDD — county provides 3,377 GDD Excellent fit

Geraniums Planting Timeline — Mount Olive, IL

Geraniums Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 18 Apr 18 – May 2
Bloom June 27 Jun 27 – 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 Transplant Outdoors
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 6b

📆 Growing Season

193 days in Macoupin County

Growing Tips for Geraniums in Mount Olive

Direct sow Geraniums outdoors after April 11 in Macoupin 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 Mount Olive, IL?

In Mount Olive, IL, plant Geraniums after the last frost (around April 11) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Mount Olive, IL for Geraniums?

Mount Olive sits in USDA Zone 6b. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.

Can Geraniums grow in Mount Olive's climate?

Yes — Geraniums grows well in Mount Olive's temperate climate. Mount Olive averages a 193-day frost-free season, with last frost around April 11 and first frost around October 21.

🌱

Your Macoupin County Garden Planner — Free

A 22-page printable planner built for Macoupin County (Zone 6b). 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 Macoupin County, IL. Local conditions may vary. Last updated: June 2026.