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When to Plant Microgreens in Orange County, CA

Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

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 Microgreens during the growing season. With low rainfall, drip irrigation is essential for growing Microgreens 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 (265 days to spare)
Start indoors: Jan 5 Transplant: Feb 2 🍅 Harvest: Feb 9 – Mar 9
Recommended (50%) ✓ Fits season (266 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: Feb 20 – Mar 20
Safe Start (90%) ✓ Fits season (227 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🍅 Harvest: Apr 9 – May 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
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

Microgreens needs ~224 GDD — county provides 4,832 GDD Excellent fit

Microgreens Planting Timeline โ€” Orange County, CA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 โ€“ Jan 30
Transplant Outdoors February 13 Feb 13 โ€“ Feb 27
Direct Sow January 23 Jan 23 โ€“ Feb 13
Fall Sowing October 16 Oct 16 โ€“ Oct 30
Harvest February 20 Feb 20 โ€“ Mar 20

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Transplant Outdoors Direct Sow Harvest
March Harvest
April โ€”
May โ€”
June โ€”
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

7โ€“21 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 10a

Growing Season

301 days

Growing Tips for Orange County

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Orange County, CA?

Orange County is in Zone 10a with an average last frost of February 13. Plan your Microgreens 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.

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