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When to Plant Tomatoes in Orange County, CA

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Orange County, California is in USDA Zone 10a. The average last spring frost is February 13 and the first fall frost is December 11, giving you a growing season of approximately 301 days.

At an elevation of 405 feet, Orange County receives approximately 13.8 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Tomatoes during the growing season. With low rainfall, drip irrigation is essential for growing Tomatoes successfully. Mulch heavily to conserve soil moisture.

Orange County, CA (Zone 10a) Year-round
301 days
Last Spring Frost February 13
301 growing days
First Fall Frost December 11

Orange County Soil Profile

Soil Type

Loam

Soil pH

5.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (160 days to spare)
Start indoors: Dec 22 Transplant: Feb 9 🍅 Harvest: Apr 13 – Jun 22
Recommended (50%) ✓ Fits season (161 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: Apr 24 – Jul 3
Safe Start (90%) ✓ Fits season (122 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🍅 Harvest: Jun 11 – Aug 20

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
1.0″/week
Watering frequency 2-3 times/week
Season total 2,606 gal / 100 sq ft
Drought risk

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

Tomatoes needs ~1,160 GDD — county provides 4,832 GDD Excellent fit

Tomatoes Planting Timeline โ€” Orange County, CA

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 โ€“ Jan 16
Transplant Outdoors February 20 Feb 20 โ€“ Mar 6
Direct Sow February 13 Feb 13 โ€“ Mar 6
Harvest April 24 Apr 24 โ€“ Jul 3

Plant 0.5" deep ยท 24" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April Harvest
May Harvest
June Harvest
July Harvest
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€“85 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 10a

Growing Season

301 days

Growing Tips for Orange County

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Level Up Your Garden

๐ŸŒพ Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35ยฐF, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Orange County, CA?

Orange County is in Zone 10a with an average last frost of February 13. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Orange County, CA?

Orange County, California is in USDA Hardiness Zone 10a. The average last spring frost is February 13 and first fall frost is December 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Orange County gardeners in Zone 10a 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 Orange County, CA. Local conditions may vary. Last updated: April 2026.