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When to Plant Mizuna in Santa Cruz County, CA

Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.

Santa Cruz County, California is in USDA Zone 9b. The average last spring frost is February 11 and the first fall frost is December 4, giving you a growing season of approximately 296 days.

At an elevation of 353 feet, Santa Cruz County receives approximately 18.3 inches of rainfall annually with predominantly loam soil. Summer highs average 94ยฐF, providing good warmth for Mizuna during the growing season. With low rainfall, drip irrigation is essential for growing Mizuna successfully. Mulch heavily to conserve soil moisture.

Santa Cruz County, CA (Zone 9b) Year-round
296 days
Last Spring Frost February 11
296 growing days
First Fall Frost December 4

Santa Cruz County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (241 days to spare)
Start indoors: Dec 31 Transplant: Jan 28 🍅 Harvest: Mar 4 – Apr 1
Recommended (50%) ✓ Fits season (233 days to spare)
Start indoors: Jan 14 Transplant: Feb 11 🍅 Harvest: Mar 18 – Apr 15
Safe Start (90%) ✓ Fits season (215 days to spare)
Start indoors: Feb 17 Transplant: Mar 17 🍅 Harvest: Apr 21 – May 19

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 2,351 gal / 100 sq ft
Drought risk

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

Mizuna needs ~769 GDD — county provides 6,088 GDD Excellent fit

Mizuna Planting Timeline โ€” Santa Cruz County, CA

Mizuna Planting Calendar

Activity When Date Range
Start Indoors January 14 Jan 14 โ€“ Jan 28
Transplant Outdoors February 11 Feb 11 โ€“ Feb 25
Direct Sow January 21 Jan 21 โ€“ Feb 11
Fall Sowing October 9 Oct 9 โ€“ Oct 23
Harvest March 18 Mar 18 โ€“ Apr 15

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Transplant Outdoors Direct Sow
March Harvest
April Harvest
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

30โ€“45 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 9b

Growing Season

296 days

Growing Tips for Santa Cruz County

Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Mizuna in Santa Cruz County, CA?

Santa Cruz County is in Zone 9b with an average last frost of February 11. Plan your Mizuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Santa Cruz County, CA?

Santa Cruz County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 11 and first fall frost is December 4.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Santa Cruz 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 Cruz County, CA. Local conditions may vary. Last updated: April 2026.