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When to Plant Tatsoi in San Bernardino County, CA

Tatsoi is a compact Asian green forming beautiful rosettes of dark, spoon-shaped leaves with a mild mustard flavor. It is extremely cold-hardy and versatile.

San Bernardino County, California is in USDA Zone 9a. The average last spring frost is February 24 and the first fall frost is November 25, giving you a growing season of approximately 274 days.

At an elevation of 1,012 feet, San Bernardino County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 97ยฐF, so Tatsoi may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Tatsoi successfully. Mulch heavily to conserve soil moisture.

San Bernardino County, CA (Zone 9a) Year-round
274 days
Last Spring Frost February 24
274 growing days
First Fall Frost November 25

San Bernardino County Soil Profile

Soil Type

Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (210 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: Mar 20 – Apr 24
Recommended (50%) ✓ Fits season (204 days to spare)
Start indoors: Jan 27 Transplant: Feb 24 🍅 Harvest: Mar 31 – May 5
Safe Start (90%) ✓ Fits season (207 days to spare)
Start indoors: Feb 7 Transplant: Mar 7 🍅 Harvest: Apr 11 – May 16

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
0.3″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,179 gal / 100 sq ft
Drought risk

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

Tatsoi needs ~967 GDD — county provides 6,256 GDD Excellent fit

Tatsoi Planting Timeline โ€” San Bernardino County, CA

Tatsoi Planting Calendar

Activity When Date Range
Start Indoors January 27 Jan 27 โ€“ Feb 10
Transplant Outdoors February 24 Feb 24 โ€“ Mar 10
Direct Sow February 3 Feb 3 โ€“ Feb 24
Fall Sowing September 30 Sep 30 โ€“ Oct 14
Harvest March 31 Mar 31 โ€“ May 5

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

35โ€“50 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 9a

Growing Season

274 days

Growing Tips for San Bernardino County

Direct sow in spring or fall. Tatsoi tolerates frost down to 15F. Harvest outer leaves or cut whole rosettes. Excellent in salads, stir-fries, or lightly wilted.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Tatsoi in San Bernardino County, CA?

San Bernardino County is in Zone 9a with an average last frost of February 24. Plan your Tatsoi planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is San Bernardino County, CA?

San Bernardino County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 24 and first fall frost is November 25.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help San Bernardino County gardeners in Zone 9a 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 San Bernardino County, CA. Local conditions may vary. Last updated: April 2026.