When to plant Geraniums in Hill County, MT
In Hill County, Geraniums is a spring-only crop. Plant May 28–June 11 once soil hits 50°F.
When to Plant Geraniums in Hill County, MT
Your June gardening checklist
Here's what deserves your attention in Hill County, Montana this month. Everything below is tailored to Zone 4a and timed around your local frost dates.
Before July arrives, get these ready
- Starting indoors: 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.
Hill County, Montana is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.
At an elevation of 5,229 feet, Hill County receives approximately 14.4 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Geraniums to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Geraniums successfully. Mulch heavily to conserve soil moisture.
Hill County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.1
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 Hill County
How your county's soil matches Geraniums's growing requirements.
Soil pH
Your soil pH (6.6–8.1) is more alkaline than Geraniums prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Hill County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Geraniums.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Geraniums.
How to Plant Geraniums
Succession Planting Geraniums
Sow every 8 weeks. Last sowing by Jun 15 to harvest before frost.
Geraniums Water Budget
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" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | — | 1.4" | 0" | ❄️ Dormant |
| May | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Jun | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Jul | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Aug | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Sep | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Hill 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 — Hill County, MT
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 26 | Feb 26 – Mar 12 |
| Transplant Outdoors | May 28 | May 28 – Jun 11 |
| Bloom | August 6 | Aug 6 – Oct 8 |
Plant 0.1" deep · 12" apart · Rows 14" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4a
📆 Growing Season
132 days in Hill County
Growing Tips for Geraniums in Hill County
Direct sow Geraniums outdoors after May 14 in Hill County when soil has warmed and frost danger has passed.
Hill County receives only 14" of rain annually. Geraniums needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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
Frequently Asked Questions
When should I plant Geraniums in Hill County, MT?
Hill County is in Zone 4a with an average last frost of May 14. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hill County, MT?
Hill County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 23.
When should I plant Geraniums in Hill County, MT?
In Hill County, MT, plant Geraniums after the last frost (around May 14) and before the first frost (around September 23). Best results when soil holds above 50°F.
What growing zone is Hill County, MT for Geraniums?
Hill County sits in USDA Zone 4a. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.
Can Geraniums grow in Hill County's climate?
Yes — Geraniums grows well in Hill County's temperate climate. Hill County averages a 132-day frost-free season, with last frost around May 14 and first frost around September 23.
Your Hill County Garden Planner — Free
A 22-page printable planner built for Hill County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.