How to Grow Radicchio
Cichorium intybus var. foliosum
Bold, bitter-sweet Italian chicory with wine-red heads — a cool fall garden standout.
By the Plants by Zone Editorial Team · Reviewed June 1, 2026
About radicchio
Radicchio is an Italian chicory grown for its compact, cabbage-like heads of deep burgundy and white leaves with a distinctive bitter-sweet flavor that mellows beautifully with cold weather and heat. Unlike most salad greens, radicchio reaches its peak quality in fall, when temperatures below 50°F stimulate the formation of anthocyanins that turn the tightly folded inner leaves a vivid wine-red. It can be eaten raw in salads, grilled or sautéed to caramelize its natural sugars, or braised with olive oil and balsamic vinegar into a silky side dish.
When to plant and harvest radicchio
Timing is relative to your frost dates. Find your USDA zone for exact dates, or browse the month-by-month calendars.
Start seeds indoors
5–6 weeks before transplanting out; for fall crop, start indoors in early July in most zones
Transplant outdoors
For fall crop: set out 10–14 weeks before the first fall frost; for spring crop: 2–4 weeks before last frost
Direct sow
Direct-sow 90–100 days before the first fall frost; or 4–6 weeks before last frost for a spring crop
Harvest
Fall through early winter; best flavor after temperatures drop below 50°F, which sweetens the heads
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How to grow radicchio step by step
- 1
Time your main crop for fall harvest — in most of the US, direct-sow or transplant outdoors in midsummer (early to mid-July) so heads develop during the cooling days of autumn.
- 2
Direct-sow seeds ⅛ in deep in a consistently moist seedbed; thin to 10–12 in apart once seedlings are 3 in tall.
- 3
Keep moisture steady and apply a 2-inch layer of compost mulch to cool the root zone during the warm start of the season.
- 4
As temperatures drop below 60°F in fall, the outer leaves will green up or fade while the tightly folded inner heart turns brilliant burgundy-red — this color shift signals the plant is nearly ready.
- 5
For Chioggia and Verona types, optionally tie the outer leaves over the head for 10–14 days before harvest to blanch and sweeten the heart further.
- 6
Harvest when the head feels firm and dense like a small cabbage, cutting at the base; cutting just above the soil level often prompts a second, smaller ratoon head in 3–4 weeks.
Common problems growing radicchio
⚠ Heads staying green and bitter (no red color)
Red coloring develops in response to cold — harvest must happen after several nights below 50°F. Time the crop for fall rather than summer, and leave plants in the garden through the first frost in mild climates.
⚠ Bolting in late spring or summer heat
Radicchio is heat-sensitive and bolts on long, warm days; grow the main crop for fall harvest, and choose bolt-resistant Chioggia varieties for spring trials.
⚠ Loosely-formed, open heads
Usually caused by planting too early in hot weather, inconsistent moisture, or overly rich nitrogen feeding; time for fall, keep moisture even, and cut back on high-nitrogen fertilizers once plants are established.
⚠ Aphids clustered on new growth
Knock colonies off with a strong water stream and apply insecticidal soap; the tight head provides harborage, so scout weekly and control early before aphids move inside the forming head.
✗ Keep away from
🧺 Harvesting radicchio
Cut radicchio heads at the base when they feel as firm and heavy as a small cabbage, typically after several nights below 50°F have deepened the color from olive-green to deep burgundy. Cutting ½ inch above soil level rather than removing the root often yields a smaller ratoon head in 3–4 weeks. Store cut heads unwashed in the refrigerator crisper, loosely wrapped in damp paper towel, for up to two weeks — they hold remarkably well, far longer than lettuce.
Radicchio: frequently asked questions
When should you plant radicchio?＋
In most regions you start seeds indoors 5–6 weeks before transplanting out; for fall crop, start indoors in early July in most zones, then transplant for fall crop: set out 10–14 weeks before the first fall frost; for spring crop: 2–4 weeks before last frost — or direct-sow 90–100 days before the first fall frost; or 4–6 weeks before last frost for a spring crop. Timing is relative to your last frost, so find your USDA hardiness zone for the exact planting dates where you live.
How do I reduce the bitterness of radicchio?＋
Bitterness is largely a function of growing conditions and preparation. Harvesting after cold nights dip below 50°F is the most important step — cold weather converts bitter compounds into sugars. For cooking, high heat (grilling, roasting, or sautéing) caramelizes the sugars and softens bitterness significantly. Soaking cut radicchio in cold water for 15–30 minutes before using it raw also takes the edge off.
Why does my radicchio stay green instead of turning red?＋
Red coloring (anthocyanins) develops in response to cold temperatures — if plants grow in warm weather throughout, the outer leaves stay green and the characteristic color never develops. The solution is timing: grow for fall harvest so the critical color-development phase coincides with nights cooling below 50°F. In warm climates, try placing a loose row cover over the bed at night to trap cold and deepen the color.
Sources & review
Written and maintained by the Plants by Zone Editorial Team. Planting times are based on USDA hardiness zones and NOAA frost-date normals, with care guidance drawn from Cooperative Extension sources. Last reviewed June 1, 2026.
USDA Plant Hardiness Zone MapNOAA U.S. climate normalsCooperative Extension
Grow radicchio in your zone
See exactly when to plant and what else to grow alongside radicchio, tailored to your USDA hardiness zone.
