When to plant Geraniums in Saint Clair, MO
Saint Clair's 200-day season only supports one Geraniums planting per year. Sow between April 17 and May 1 for the best chance at full maturity before October 27.
When to Plant Geraniums in Saint Clair, MO
June in the garden — Franklin County, Missouri
A quick June briefing for Franklin County, Missouri gardeners — what's urgent, what's next, and what can wait.
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Indoor seed-starting week for geraniums
Label every cell. You will absolutely forget which is which otherwise.
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Collect geraniums at their peak
If you can't use it all right away, check the food-preservation section of your planner.
July prep starts now
- First harvests: geraniums
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.
Saint Clair, Missouri is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 27, giving you a growing season of approximately 200 days.
At an elevation of 1,180 feet, Franklin County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Geraniums during the growing season.
Saint Clair Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.8
Drainage
Well Drained
Geraniums Planting Risk Windows
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 Saint Clair
How your county's soil matches Geraniums's growing requirements.
Soil pH
Your soil pH (5.7–6.8) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Franklin County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Geraniums.
How to Plant Geraniums
Succession Planting Geraniums
Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.
Geraniums Water Budget
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4" | 0.3" | 💧 Light watering |
| May | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jun | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 2.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Franklin 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 Planting Timeline — Saint Clair, MO
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 30 | Jan 30 – Feb 13 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Bloom | June 26 | Jun 26 – Oct 2 |
Plant 0.1" deep · 12" apart · Rows 14" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · Only during dry spells
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
200 days in Franklin County
Growing Tips for Geraniums in Saint Clair
Direct sow Geraniums outdoors after April 10 in Franklin 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 →
Geraniums in Other Locations
When should I plant Geraniums in Saint Clair, MO?
In Saint Clair, MO, plant Geraniums after the last frost (around April 10) and before the first frost (around October 27). Best results when soil holds above 50°F.
What growing zone is Saint Clair, MO for Geraniums?
Saint Clair sits in USDA Zone 6b. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.
Can Geraniums grow in Saint Clair's climate?
Yes — Geraniums grows well in Saint Clair's temperate climate. Saint Clair averages a 200-day frost-free season, with last frost around April 10 and first frost around October 27.
Your Franklin County Garden Planner — Free
A 22-page printable planner built for Franklin 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.