When to plant Geraniums in Rolla,
Rolla sits in cold Zone 6b. Plant Geraniums April 16–April 30 for the single annual harvest; the October 24 first frost closes the window.
When to Plant Geraniums in Rolla, MO
This month in Rolla, MO
Your garden in Rolla, MO is working on a schedule, even when you're not. Here's where you should be this June.
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Fire up the seed-starting tray: geraniums
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
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Pick geraniums
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
July will be here before you know it — start on
- 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.
Rolla, Missouri is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 24, giving you a growing season of approximately 198 days.
At an elevation of 1,057 feet, Phelps County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Geraniums during the growing season.
Rolla Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-7
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 Rolla
How your county's soil matches Geraniums's growing requirements.
Soil pH
Your soil pH (5.2–7.0) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Phelps County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Geraniums.
How to Plant Geraniums
Succession Planting Geraniums
Sow every 8 weeks. Last sowing by Jul 16 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| May | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Oct | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Nov | — | 3" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Phelps 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 — Rolla, MO
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 29 | Jan 29 – Feb 12 |
| Transplant Outdoors | April 16 | Apr 16 – Apr 30 |
| Bloom | June 25 | Jun 25 – Oct 1 |
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 | — |
| 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
198 days in Phelps County
Growing Tips for Geraniums in Rolla
Direct sow Geraniums outdoors after April 09 in Phelps 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 Rolla, ?
In Rolla, , plant Geraniums after the last frost (around April 9) and before the first frost (around October 24). Best results when soil holds above 50°F.
What growing zone is Rolla, for Geraniums?
Rolla sits in USDA Zone 6b. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.
Can Geraniums grow in Rolla's climate?
Yes — Geraniums grows well in Rolla's temperate climate. Rolla averages a 198-day frost-free season, with last frost around April 9 and first frost around October 24.
Your Phelps County Garden Planner — Free
A 22-page printable planner built for Phelps 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.