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When to Plant Cardoon in Hillsborough County, FL

Hillsborough County, Florida Zone 10a May

Your May game plan for Hillsborough County, Florida

Your Hillsborough County, Florida garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost January 25
Avg. first frost December 20
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
Before June arrives, get these ready
  • First harvests: cardoon

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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.

Hillsborough County, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 20, giving you a growing season of approximately 329 days.

At an elevation of 63 feet, Hillsborough County receives approximately 54.4 inches of rainfall annually with predominantly sand soil. Summer highs average 98°F, so Cardoon may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Cardoon will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cardoon root diseases.

Hillsborough County, FL (Zone 10a) Year-round
329 days
Last Spring Frost January 25
329 growing days
First Fall Frost December 20

Hillsborough County Soil Profile

Soil Type

Sand

Soil pH

4.9-5.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (144 days to spare)
Transplant: Jan 31 🍅 Harvest: Jun 6 – Jul 18
Recommended (50%) ✓ Fits season (147 days to spare)
Transplant: Feb 8 🍅 Harvest: Jun 14 – Jul 26
Safe Start (90%) ✓ Fits season (123 days to spare)
Transplant: Mar 9 🍅 Harvest: Jul 13 – Aug 24

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 Hillsborough County

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

Soil pH

Your soil pH (4.9–5.9) is more acidic than Cardoon prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Hillsborough County warms quickly in spring but drains fast. Cardoon will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Cardoon.

Organic Matter

Organic matter is low (1.5%). Add 2-3 inches of compost before planting Cardoon.

How to Plant Cardoon

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 2,142 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 4.3" 2.3" 2" 💧 Light watering
Feb 4.3" 2.7" 1.6" 💧 Light watering
Mar 4.3" 2.9" 1.4" 💧 Light watering
Apr 4.3" 2.1" 2.2" 🚿 Regular watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 8.1" 0" ✅ Rainfall sufficient
Jul 4.3" 8" 0" ✅ Rainfall sufficient
Aug 4.3" 8" 0" ✅ Rainfall sufficient
Sep 4.3" 7.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 4.3" 2.4" 1.9" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Hillsborough 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 ~3,172 GDD — county provides 7,755 GDD Excellent fit

Cardoon Planting Timeline — Hillsborough County, FL

Cardoon Planting Calendar

Activity When Date Range
Transplant Outdoors February 8 Feb 8 – Feb 22
Harvest June 14 Jun 14 – Jul 26

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

Month-by-Month Timeline

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

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: too_acidic

🗺️ USDA Zone

Zone 10a

📆 Growing Season

329 days in Hillsborough County

Growing Tips for Cardoon in Hillsborough County

Direct sow Cardoon outdoors after January 25 in Hillsborough County when soil has warmed and frost danger has passed.

Sandy soil in Hillsborough County dries quickly — mulch Cardoon with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 98°F in Hillsborough County, provide afternoon shade for Cardoon and water deeply in the morning.

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 Hillsborough County, FL?

Hillsborough County is in Zone 10a with an average last frost of January 25. Plan your Cardoon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hillsborough County, FL?

Hillsborough County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 25 and first fall frost is December 20.

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Your Hillsborough County Garden Planner — Free

A 24-page printable planner built for Hillsborough County (Zone 10a). 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 Hillsborough County, FL. 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.