When to plant Geraniums in Pacifica, CA
In Pacifica, Geraniums is a spring-only crop. Plant December 7–December 21 once soil hits 50°F.
When to Plant Geraniums in Pacifica, CA
San Mateo County, California gardeners: here's your June plan
June is a pivotal month for San Mateo County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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It's harvest week for geraniums
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Get ahead of July
- 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.
Pacifica, California is in USDA Zone 10a. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.
At an elevation of 277 feet, San Mateo County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 81°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.
Pacifica Soil Profile
Soil Type
Loam
Soil pH
6.8-7.2
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 Pacifica
How your county's soil matches Geraniums's growing requirements.
Soil pH
Your soil pH (6.8–7.2) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in San Mateo 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 (2.6%). Annual compost additions will help Geraniums.
How to Plant Geraniums
Succession Planting Geraniums
Sow every 8 weeks. Last sowing by Sep 03 to harvest before frost.
Geraniums Water Budget
Water stress score is 8/10 — 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 | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Feb | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Mar | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Apr | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| May | 4.3" | 0.4" | 3.9" | 🚿 Regular watering |
| Jun | 4.3" | 0.1" | 4.2" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Oct | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Nov | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Dec | 4.3" | 2.9" | 1.4" | 💧 Light watering |
Water needs are for active growing months only (Jan–Dec in San Mateo 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 — Pacifica, CA
Geraniums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | November 9 | Nov 9 – Nov 23 |
| Transplant Outdoors | December 7 | Dec 7 – Dec 21 |
| Bloom | February 15 | Feb 15 – Sep 13 |
Plant 0.1" deep · 14" apart · Rows 16" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Bloom |
| March | Bloom |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | Start Indoors |
| December | Transplant Outdoors |
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: acceptable
🗺️ USDA Zone
Zone 10a
📆 Growing Season
328 days in San Mateo County
Growing Tips for Geraniums in Pacifica
Direct sow Geraniums outdoors after January 18 in San Mateo County when soil has warmed and frost danger has passed.
San Mateo County receives only 17" 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
When should I plant Geraniums in Pacifica, CA?
In Pacifica, CA, plant Geraniums after the last frost (around January 18) and before the first frost (around December 12). Best results when soil holds above 50°F.
What growing zone is Pacifica, CA for Geraniums?
Pacifica sits in USDA Zone 10a. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.
Can Geraniums grow in Pacifica's climate?
Yes — Geraniums grows well in Pacifica's temperate climate. Pacifica averages a 329-day frost-free season, with last frost around January 18 and first frost around December 12.
Your San Mateo County Garden Planner — Free
A 22-page printable planner built for San Mateo County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.