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When to Plant Tatsoi in Monterey County, CA

Monterey County, California Zone 9b May

Your May gardening checklist

Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 13
Avg. first frost November 17
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. Bring in the tatsoi

    If you can't use it all right away, check the food-preservation section of your planner.

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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.

Monterey County, California is in USDA Zone 9b. The average last spring frost is March 13 and the first fall frost is November 17, giving you a growing season of approximately 249 days.

At an elevation of 260 feet, Monterey County receives approximately 12.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Tatsoi during the growing season. With low rainfall, drip irrigation is essential for growing Tatsoi successfully. Mulch heavily to conserve soil moisture.

Monterey County, CA (Zone 9b) Long season
249 days
Last Spring Frost March 13
249 growing days
First Fall Frost November 17

Monterey County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (178 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🍅 Harvest: Apr 3 – May 8
Recommended (50%) ✓ Fits season (179 days to spare)
Start indoors: Feb 13 Transplant: Mar 13 🍅 Harvest: Apr 17 – May 22
Safe Start (90%) ✓ Fits season (144 days to spare)
Start indoors: Apr 19 Transplant: May 17 🍅 Harvest: Jun 21 – Jul 26

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.

Soil Compatibility in Monterey County

How your county's soil matches Tatsoi's growing requirements.

Soil pH

Your soil pH (6.7–7.2) is within Tatsoi's preferred range (6.0–7.5).

Soil Texture

The loam soil in Monterey County is excellent for Tatsoi — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Tatsoi.

How to Plant Tatsoi

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Tatsoi

8
successive plantings in your 249-day season

Sow every 4 weeks. Last sowing by Sep 28 to harvest before frost.

For a dedicated fall crop, sow by Sep 22.

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 2,099 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Tatsoi

Tatsoi needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Tatsoi Needs Rainfall You Supplement Action
Jan 2.7" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 4.3" 2.1" 2.2" 🚿 Regular watering
Apr 4.3" 1" 3.3" 🚿 Regular watering
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.1" 4.2" 🚿 Regular watering
Oct 4.3" 0.5" 3.8" 🚿 Regular watering
Nov 4.3" 1.2" 3.1" 🚿 Regular watering
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Monterey County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tatsoi Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Tatsoi needs ~839 GDD — county provides 4,917 GDD Excellent fit

Tatsoi Planting Timeline — Monterey County, CA

Tatsoi Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors March 13 Mar 13 – Mar 27
Direct Sow February 20 Feb 20 – Mar 13
Harvest April 17 Apr 17 – May 22
Fall Sowing September 22 Sep 22 – Oct 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

249 days in Monterey County

Growing Tips for Tatsoi in Monterey County

Direct sow Tatsoi outdoors after March 13 in Monterey County when soil has warmed and frost danger has passed.

Your generous 249.0-day season in Monterey County allows multiple plantings of Tatsoi. Sow every 17.0 days for continuous harvest.

Common pests for Tatsoi in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Monterey County receives only 12" of rain annually. Tatsoi needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tatsoi in Monterey County, CA?

Monterey County is in Zone 9b with an average last frost of March 13. Plan your Tatsoi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monterey County, CA?

Monterey County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 13 and first fall frost is November 17.

🌱

Your Monterey County Garden Planner — Free

A 24-page printable planner built for Monterey County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Monterey County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.