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When to Plant Corn in Santa Clara County, CA

Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

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 Corn during the growing season. With low rainfall, drip irrigation is essential for growing Corn 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 (176 days to spare)
Transplant: Feb 1 🍅 Harvest: Apr 5 – May 31
Recommended (50%) ✓ Fits season (168 days to spare)
Transplant: Feb 19 🍅 Harvest: Apr 23 – Jun 18
Safe Start (90%) ✓ Fits season (121 days to spare)
Transplant: Apr 24 🍅 Harvest: Jun 26 – Aug 21

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

Corn needs ~1,520 GDD — county provides 5,472 GDD Excellent fit

Corn Planting Timeline โ€” Santa Clara County, CA

Corn Planting Calendar

Activity When Date Range
Direct Sow February 26 Feb 26 โ€“ Mar 19
Harvest April 30 Apr 30 โ€“ Jun 25

Plant 1" deep ยท 12" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Direct Sow
March Direct Sow
April Harvest
May Harvest
June Harvest
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 9b

Growing Season

287 days

Growing Tips for Santa Clara County

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Level Up Your Garden

Frequently Asked Questions

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

Santa Clara County is in Zone 9b with an average last frost of February 19. Plan your Corn 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.

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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 Santa Clara County, CA. Local conditions may vary. Last updated: April 2026.