When to Plant Radicchio in USDA Zone 4a
Your May planting checklist for Zone 4a
May is a pivotal month for Zone 4a gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Plant out radicchio
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
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Direct-sow radicchio
Your soil is warming°F — warm enough for these to germinate without babying.
Looking ahead to June
- Starting indoors: radicchio
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.
In Zone 4a, the average last spring frost is around May 6 and the first fall frost is around September 28, giving you a growing season of approximately 145 days.
Radicchio Planting Timeline — Zone 4a
Where Is USDA Zone 4a?
The map below highlights the states that contain Zone 4a. Click any state to see the Radicchio planting schedule for that location.
Radicchio Planting Calendar — Zone 4a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 25 | Mar 25 – Apr 8 |
| Transplant Outdoors | May 6 | May 6 – May 20 |
| Direct Sow | April 29 | Apr 29 – May 20 |
| Harvest | July 8 | Jul 8 – Aug 12 |
| Fall Sowing | July 6 | Jul 6 – Jul 20 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Free Zone 4a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4a with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
Days to Maturity
60–80 days
Soil pH
6 – 7
Zone Temperature Range
°F to °F average annual minimum
Growing Season
145 days (Zone average)
Planting Specifications
| Planting Depth | 0.5 inches |
| Plant Spacing | 6 inches apart |
| Row Spacing | 12 inches between rows |
Succession Planting Radicchio in Zone
Sow every 6.9 weeks for continuous harvest throughout the season.
Growing Tips for Radicchio in Zone
Zone has a short growing season (~145 days). Start Radicchio indoors early and use season-extension techniques like row covers and cold frames.
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
Avoid Planting Near
The Gardener's Encyclopedia to Companion Planting
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Saving Radicchio Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Radicchio in Other Zones
Radicchio by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Radicchio in Zone 4a?
In Zone 4a, plan your Radicchio planting around the average last frost date of May 6. Start seeds indoors around March 25. Direct sow outdoors around April 29. Transplant seedlings around May 6.
Can Radicchio grow in Zone 4a?
Yes, Radicchio can grow well in Zone 4a, hardy in USDA zones 4a through 10b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Radicchio (60-80 days to maturity).
When can I harvest Radicchio in Zone 4a?
In Zone 4a, expect to harvest Radicchio from July 8 – August 12. Radicchio takes 60-80 days from planting to harvest.
What is the last frost date for Zone 4a?
The average last spring frost in Zone 4a is around May 6, and the first fall frost is around September 28. This gives a growing season of approximately 145 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Radicchio?
Good companion plants for Radicchio include Carrots, Lettuce, Endive. These companions can help with pest control, pollination, and nutrient sharing.
Your Free Printable Garden Planner
A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.