Climate matters. This page is a practical baseline. Confirm cultivar, local frost/heat conditions, mature size and regional restrictions before planting.
Radicchio — Growing reference
| Scientific name | Cichorium intybus var. foliosum |
|---|---|
| Seed germination (days) | 5–10 |
| Soil temperature for germination (°C) | 10–23.9 |
| First harvest or flowering (days) | 80–100 |
| Measured from | Seed |
| Plant spacing (cm) | 25.4–35.6 |
| Mature height (cm) | 20.3–30.5 |
| Mature spread (cm) | 25.4–35.6 |
| USDA hardiness zones | 4–10 |
| Light | Full sun |
| Water | Moderate |
| Sowing method | Direct sow |
Growing directions
Sow seed 1/4 in deep and thin to 10–14 in; radicchio produces loose, green summer foliage before forming its characteristic red and white tight head as days shorten and temperatures fall. Cut back summer foliage to about 1 in when plants look tired and cool temperatures arrive; new heads will form from the crown within 3–4 weeks. Harvest compact heads by cutting at the base once they feel firm and the color is deep burgundy. Hard frost may damage outer leaves but the inner head often survives.
Source and local conditions
Typical planning ranges from OpenPlantDB (CC0). Cultivar, climate, season and growing method can change these values. Confirm the seed label and local guidance before planting.
Source & verification
OpenPlantDB · CC0