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When to Plant Cardoon in Monterey County, CA

Monterey County, California Zone 9b May

May to-do list for Monterey County, California

A quick May briefing for Monterey County, California gardeners — what's urgent, what's next, and what can wait.

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

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Cardoon is a large thistle relative of the artichoke, grown for its edible leaf stalks. It has dramatic silvery foliage and makes a striking ornamental as well.

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 Cardoon during the growing season. With low rainfall, drip irrigation is essential for growing Cardoon 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
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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 (66 days to spare)
Transplant: Mar 13 🍅 Harvest: Jul 17 – Aug 28
Recommended (50%) ✓ Fits season (67 days to spare)
Transplant: Mar 27 🍅 Harvest: Jul 31 – Sep 11
Safe Start (90%) ✓ Fits season (32 days to spare)
Transplant: May 31 🍅 Harvest: Oct 4 – Nov 15

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 Cardoon's growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Cardoon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

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 Cardoon

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

Month Cardoon 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.

Cardoon 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.

Cardoon needs ~2,666 GDD — county provides 4,917 GDD Excellent fit

Cardoon Planting Timeline — Monterey County, CA

Cardoon Planting Calendar

Activity When Date Range
Transplant Outdoors March 27 Mar 27 – Apr 10
Harvest July 31 Jul 31 – Sep 11

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April Transplant Outdoors
May
June
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

120–150 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

249 days in Monterey County

Growing Tips for Cardoon in Monterey County

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

Common pests for Cardoon in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

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

General growing tips

Blanch stalks by wrapping with cardboard or tying leaves together 3-4 weeks before harvest. Provide deep, rich soil and consistent moisture. Protect from hard frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cardoon in Monterey County, CA?

Monterey County is in Zone 9b with an average last frost of March 13. Plan your Cardoon 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.

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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.