When to Plant Radicchio in Greater Sudbury, ON
Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.
Greater Sudbury, Ontario is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 8, giving you a growing season of approximately 167 days.
At an elevation of 1,141 feet, Greater Sudbury receives approximately 29.7 inches of rainfall annually with predominantly clay loam soil. Summer highs average 77°F, so choose short-season varieties of Radicchio to ensure they mature before fall. Clay soil retains moisture well for Radicchio, but amend with compost to improve drainage and prevent root rot.
Greater Sudbury Soil Profile
Soil Type
Clay Loam
Soil pH
6.0-7.0
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.
How to Plant Radicchio
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
Monthly Watering Guide for Radicchio
Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Radicchio Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 3" | 2.9" | 0.1" | 💧 Light watering |
| May | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.7" | 0.3" | 💧 Light watering |
| Oct | 3" | 2" | 1" | 💧 Light watering |
| Nov | — | 1.8" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Greater Sudbury). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Radicchio 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.
Radicchio Planting Timeline — Greater Sudbury, ON
Radicchio Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 20 | Mar 20 – Apr 3 |
| Transplant Outdoors | April 24 | Apr 24 – May 8 |
| Direct Sow | April 10 | Apr 10 – May 1 |
| Harvest | June 26 | Jun 26 – Jul 31 |
| Fall Sowing | July 30 | Jul 30 – Aug 13 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
167 days in Greater Sudbury
Growing Tips for Radicchio in Greater Sudbury
Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.
Companion Planting
Good Companions
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Radicchio in Other Locations
Frequently Asked Questions
When should I plant Radicchio in Greater Sudbury, ON?
Greater Sudbury is in Zone 5b with an average last frost of April 24. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.
What planting zone is Greater Sudbury, ON?
Greater Sudbury, Ontario is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 8.
Plan Your Garden with Confidence
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