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When to Plant Cardoon in Calaveras County, CA

Calaveras County, California Zone 9a April

April in Calaveras County, California — your action list

If you only do a handful of things in the garden this April, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 8
Avg. first frost November 12
Soil temp (4") 59°F
Watering High
Pest pressure High
Daylight 13 hrs
  1. Move cardoon into the garden

    Frost risk is low now in Calaveras County, California. If you've been covering beds overnight, you can stop.

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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.

Calaveras County, California is in USDA Zone 9a. The average last spring frost is April 8 and the first fall frost is November 12, giving you a growing season of approximately 218 days.

At an elevation of 2,363 feet, Calaveras County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Cardoon to ensure they mature before fall.

Calaveras County, CA (Zone 9a) Long season
218 days
Last Spring Frost April 8
218 growing days
First Fall Frost November 12
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Calaveras County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Transplant: Mar 16 🍅 Harvest: Jul 20 – Aug 31
Recommended (50%) ✓ Fits season (36 days to spare)
Transplant: Apr 22 🍅 Harvest: Aug 26 – Oct 7
Safe Start (90%) ✓ Fits season (36 days to spare)
Transplant: May 22 🍅 Harvest: Sep 25 – Nov 6

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 Calaveras County

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

Soil pH

Your soil pH (6.5–7.6) overlaps with Cardoon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,207 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 5.4" 0" ❄️ Dormant
Feb 4.8" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 4.3" 2.4" 1.9" 💧 Light watering
May 4.3" 0.7" 3.6" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.3" 4" 🚿 Regular watering
Oct 4.3" 1" 3.3" 🚿 Regular watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Calaveras 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 ~1,654 GDD — county provides 2,670 GDD Excellent fit

Cardoon Planting Timeline — Calaveras County, CA

Cardoon Planting Calendar

Activity When Date Range
Transplant Outdoors April 22 Apr 22 – May 6
Harvest August 26 Aug 26 – Oct 7

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

120–150 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

218 days in Calaveras County

Growing Tips for Cardoon in Calaveras County

Direct sow Cardoon outdoors after April 08 in Calaveras 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.

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 Calaveras County, CA?

Calaveras County is in Zone 9a with an average last frost of April 8. Plan your Cardoon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calaveras County, CA?

Calaveras County, California is in USDA Hardiness Zone 9a. The average last spring frost is April 8 and first fall frost is November 12.

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Your Calaveras County Garden Planner — Free

A 24-page printable planner built for Calaveras County (Zone 9a). 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 Calaveras County, CA. Local conditions may vary. Last updated: April 2026.

Sources & credits

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