When to Plant Geraniums in Jefferson County, PA
Your July game plan for Jefferson County, Pennsylvania
We've pulled the most time-sensitive tasks for Jefferson County, Pennsylvania this July and put them front and centre. Tackle them in order.
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Start geraniums under lights
These need a head start before your last frost (May 18). Sow into cells now so you're ready to transplant in a few weeks.
August 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.
Jefferson County, Pennsylvania is in USDA Zone 6a. The average last spring frost is May 18 and the first fall frost is October 7, giving you a growing season of approximately 142 days.
At an elevation of 1,026 feet, Jefferson County receives approximately 42.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Geraniums to ensure they mature before fall.
Jefferson County Soil Profile
Soil Type
Silt Loam
Soil pH
4.8-6.4
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 Jefferson County
How your county's soil matches Geraniums's growing requirements.
Soil pH
Your soil pH (4.8–6.4) is more acidic than Geraniums prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Jefferson 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
Succession Planting Geraniums
Sow every 8 weeks. Last sowing by Jun 29 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 | — | 2.5" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 3.9" | 0" | ❄️ Dormant |
| Apr | — | 3.8" | 0" | ❄️ Dormant |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Nov | — | 3.4" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Jefferson 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 — Jefferson County, PA
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | May 25 | May 25 – Jun 8 |
| Bloom | August 3 | Aug 3 – Nov 2 |
Plant 0.1" deep · 12" apart · Rows 14" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6a
📆 Growing Season
142 days in Jefferson County
Growing Tips for Geraniums in Jefferson County
Direct sow Geraniums outdoors after May 18 in Jefferson 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
Frequently Asked Questions
When should I plant Geraniums in Jefferson County, PA?
Jefferson County is in Zone 6a with an average last frost of May 18. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, PA?
Jefferson County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is May 18 and first fall frost is October 7.
Your Jefferson County Garden Planner — Free
A 22-page printable planner built for Jefferson County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.