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When to Plant Cucumber in San Francisco County, CA

San Francisco County, California Zone 10b May

May in San Francisco County, California — your action list

May is a pivotal month for San Francisco County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 23
Avg. first frost November 27
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Harvest cucumber as they ripen

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

June will be here before you know it — start on
  • First harvests: cucumber

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Cucumbers are a warm-season vine crop available in slicing and pickling varieties. They are prolific producers when given warmth, moisture, and a trellis to climb.

San Francisco County, California is in USDA Zone 10b. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.

At an elevation of 412 feet, San Francisco County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Cucumber during the growing season. With low rainfall, drip irrigation is essential for growing Cucumber successfully. Mulch heavily to conserve soil moisture.

San Francisco County, CA (Zone 10b) Year-round
277 days
Last Spring Frost February 23
277 growing days
First Fall Frost November 27

San Francisco County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (174 days to spare)
Start indoors: Jan 5 Transplant: Feb 9 🍅 Harvest: Apr 6 – Jun 1
Recommended (50%) ✓ Fits season (158 days to spare)
Start indoors: Jan 26 Transplant: Mar 2 🍅 Harvest: Apr 27 – Jun 22
Safe Start (90%) ✓ Fits season (140 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jun 8 – Aug 3

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 San Francisco County

How your county's soil matches Cucumber's growing requirements.

Soil pH

Your soil pH (6.2–7.2) overlaps with Cucumber's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in San Francisco County is excellent for Cucumber — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Cucumber.

How to Plant Cucumber

0.5"
Planting Depth
24"
Between Plants
48"
Between Rows

Succession Planting Cucumber

6
successive plantings in your 277-day season

Sow every 5.7 weeks. Last sowing by Sep 18 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.2″/week
You supply
1.6″/week
Watering frequency 2-3 times/week
Season total 3,848 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Cucumber

Cucumber needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Cucumber Needs Rainfall You Supplement Action
Jan 2.3" 0" ❄️ Dormant
Feb 6.5" 3.1" 3.4" 🚿 Regular watering
Mar 6.5" 2.2" 4.3" 🚿 Regular watering
Apr 6.5" 1.2" 5.3" 🚿 Regular watering
May 6.5" 0.3" 6.2" 🚿 Regular watering
Jun 6.5" 0.1" 6.4" 🚿 Regular watering
Jul 6.5" 0" 6.5" 🚿 Regular watering
Aug 6.5" 0" 6.5" 🚿 Regular watering
Sep 6.5" 0.1" 6.4" 🚿 Regular watering
Oct 6.5" 0.6" 5.9" 🚿 Regular watering
Nov 6.5" 1.4" 5.1" 🚿 Regular watering
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in San Francisco County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Cucumber 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.

Cucumber needs ~870 GDD — county provides 4,031 GDD Excellent fit

Cucumber Planting Timeline — San Francisco County, CA

Cucumber Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 – Feb 9
Transplant Outdoors March 2 Mar 2 – Mar 16
Direct Sow February 23 Feb 23 – Mar 16
Harvest April 27 Apr 27 – Jun 22

Plant 0.5" deep · 24" apart · Rows 48" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow
April Harvest
May Harvest
June Harvest
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10b

📆 Growing Season

277 days in San Francisco County

Growing Tips for Cucumber in San Francisco County

Direct sow Cucumber outdoors after February 23 in San Francisco County when soil has warmed and frost danger has passed.

Common pests for Cucumber in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

San Francisco County receives only 14" of rain annually. Cucumber needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost or start indoors 3 weeks early. Provide a trellis for vining types to save space and improve air circulation. Harvest frequently to encourage production.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Sage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cucumber in San Francisco County, CA?

San Francisco County is in Zone 10b with an average last frost of February 23. Plan your Cucumber planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Francisco County, CA?

San Francisco County, California is in USDA Hardiness Zone 10b. The average last spring frost is February 23 and first fall frost is November 27.

🌱

Your San Francisco County Garden Planner — Free

A 24-page printable planner built for San Francisco County (Zone 10b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for San Francisco County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.