When to Plant Cardoon in Union County, NC
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.
Union County, North Carolina is in USDA Zone 7b. The average last spring frost is March 26 and the first fall frost is November 4, giving you a growing season of approximately 223 days.
At an elevation of 1,049 feet, Union County receives approximately 53.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 88°F, providing good warmth for Cardoon during the growing season. Clay soil retains moisture well for Cardoon, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cardoon root diseases.
Union County Soil Profile
Soil Type
Clay Loam
Soil pH
5.4-6.8
Drainage
Well Drained
Plant Planting Risk Windows
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 Union County
How your county's soil matches Cardoon's growing requirements.
Soil pH
Your soil pH (5.4–6.8) overlaps with Cardoon's range (6.0–7.5), though not a perfect match.
Soil Texture
The clay loam soil in Union County is excellent for Cardoon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Cardoon.
How to Plant Cardoon
Plant Water Budget
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" | 0" | ❄️ Dormant |
| Feb | — | 5" | 0" | ❄️ Dormant |
| Mar | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| May | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Oct | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Nov | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Dec | — | 4.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Union 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 Planting Timeline — Union County, NC
Cardoon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 9 | Apr 9 – Apr 23 |
| Harvest | August 13 | Aug 13 – Sep 24 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | — |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
120–150 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
223 days in Union County
Growing Tips for Cardoon in Union County
Direct sow Cardoon outdoors after March 26 in Union County when soil has warmed and frost danger has passed.
With Union County's clay soil (34% clay), work in 3-4 inches of compost before planting Cardoon. Avoid tilling when soil is wet to prevent compaction.
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
Check more plant combinations with our Companion Planting Checker →
Cardoon in Other Locations
Frequently Asked Questions
When should I plant Cardoon in Union County, NC?
Union County is in Zone 7b with an average last frost of March 26. Plan your Cardoon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, NC?
Union County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is March 26 and first fall frost is November 4.
Plan Your Garden with Confidence
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