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When to Plant Lettuce in Santa Clara County, CA

Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

Santa Clara County, California is in USDA Zone 9b. The average last spring frost is February 19 and the first fall frost is December 3, giving you a growing season of approximately 287 days.

At an elevation of 455 feet, Santa Clara County receives approximately 15.5 inches of rainfall annually with predominantly loam soil. Summer highs average 92ยฐF, providing good warmth for Lettuce during the growing season. With low rainfall, drip irrigation is essential for growing Lettuce successfully. Mulch heavily to conserve soil moisture.

Santa Clara County, CA (Zone 9b) Year-round
287 days
Last Spring Frost February 19
287 growing days
First Fall Frost December 3

Santa Clara County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (190 days to spare)
Start indoors: Jan 4 Transplant: Feb 1 🍅 Harvest: Mar 8 – May 17
Recommended (50%) ✓ Fits season (182 days to spare)
Start indoors: Jan 22 Transplant: Feb 19 🍅 Harvest: Mar 26 – Jun 4
Safe Start (90%) ✓ Fits season (135 days to spare)
Start indoors: Mar 27 Transplant: Apr 24 🍅 Harvest: May 29 – Aug 7

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,381 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Lettuce needs ~855 GDD — county provides 5,472 GDD Excellent fit

Lettuce Planting Timeline โ€” Santa Clara County, CA

Lettuce Planting Calendar

Activity When Date Range
Start Indoors January 22 Jan 22 โ€“ Feb 5
Transplant Outdoors February 19 Feb 19 โ€“ Mar 5
Direct Sow January 29 Jan 29 โ€“ Feb 19
Fall Sowing October 8 Oct 8 โ€“ Oct 22
Harvest March 26 Mar 26 โ€“ Jun 4

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 9b

Growing Season

287 days

Growing Tips for Santa Clara County

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Level Up Your Garden

๐ŸŒพ Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35ยฐF, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Santa Clara County, CA?

Santa Clara County is in Zone 9b with an average last frost of February 19. Plan your Lettuce planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Santa Clara County, CA?

Santa Clara County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 19 and first fall frost is December 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Santa Clara County gardeners in Zone 9b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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