Radicchio
Radicchio is a vegetable in the Asteraceae family. It grows best in full sun with medium moisture, and is listed for USDA zones 3-13. Plants reach harvest about 55–100 days after planting and sit about 12 inches apart.
Varieties
6 from Seeds Now & True Leaf Market · sorted by days to maturity▸Classic Red55–75 days
Grows well with containers; Grows well with raised beds; Matures in <90 days; Super easy to grow
Radicchio is sometimes also referred to as the Italian chicory They're grown as a leaf vegetable White-veined red leaves Excellent grilled or roasted How to Grow Organic Radicchio from Seed Days to Maturity | 65 days
View on Seeds Now ↗▸Castelfranco60–75 days
Heirloom; Non-GMO; Vegetable; Annual
60-75 Days to maturity. Cichorium intybus. Castelfranco Endive Vegetable Seeds. Non-GMO, annual, open-pollinated, heirloom seeds. A somewhat unique endive that is a cross between Radicchio di Treviso and broadleaf endive. It produces a rounded or somewhat conical central head surrounded by many outer leaves, creating a flower-like shape that gives it one of its common names: “Winter Rose”. The leaves are creamy white to pale green with purple, red, and burgundy speckles and flecks. They have wavy, serrated edges contributing to the floral look. The flavor is a delicate balance of mild bitterness and subtle sweetness, with a tender, crisp texture. A crop better suited to fall/winter culture, as cool weather enhances the coloration. In Italy, this strain is often harvested as a full head with enough root attached to keep the form together, then carefully hand-opened to produce the striking “Rose” shape.
View on True Leaf Market ↗▸Castelfranco (Clearance)60–75 days
Heirloom; Non-GMO; Vegetable; Annual
41%-49% Germination - Non-refundable clearance seeds. 60-75 Days to maturity. Castelfranco Endive Seeds. A unique endive that is a cross between Radicchio di Treviso and broadleaf endive. It produces a rounded or somewhat conical central head surrounded by many outer leaves, creating a flower-like shape that gives it one of its common names: “Winter Rose”. The leaves are creamy white to pale green with purple, red, and burgundy speckles and flecks. These clearance Castelfranco Endive seeds are 21%-29% below germination standards. Approx 11,000 seeds/oz.
View on True Leaf Market ↗▸Red Treviso65–100 days
Heirloom; Non-GMO; Container; Vegetable; Annual
65-100 days. Cichorium endivia. Red Treviso Endive Seeds. Non-GMO, annual, heirloom, open-pollinated. This crop is suitable for garden plots, raised beds, and containers. Red Treviso is a classic Italian chicory from Treviso that produces elongated, romaine-like heads that turn deep red with crisp white ribs in cool weather, with tart, pleasantly bitter flavor for salads, grilling, and braising. ~25,500 seeds/oz.
View on True Leaf Market ↗▸Rouge de Verona68–92 days
Heirloom; Vegetable; Annual
Rouge De Verona Radicchio is an heirloom plant that can be compared to a cross between a cabbage and lettuce. Ready in about 80 days, Rouge De Verona can be used for its leaves and root, and has a bitter and spicy taste. Typically the bitter leaves are eaten in salads, but can be cooked as well.
View on True Leaf Market ↗▸Palla Rosa80–85 days
Heirloom; Vegetable; Annual
Heirloom and Non-GMO Palla Rosa Radicchio is ready in 80-85 days in the garden. Radicchio is growing in popularity, and is known for its red leaves with white veins. Palla Rosa has one of the best color contrasts of all the Radicchios as it grows to 4 inchs in diameter. Radicchio has a bitter, spicy, tangy taste that gets sweeter when cooked.
View on True Leaf Market ↗
Plant spacing
In a square-foot bed, space radicchio about 12 in apart — that fits 1 plant in each 1-foot square (1×1). Wider rows or containers space the same.
Plan your radicchio planting
Add radicchio to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.
Start your free plan →At a glance
Storing & preserving
Most keep best refrigerated; storage crops prefer a cool, dry spot.
- Freeze: Blanch briefly, cool, then freeze — keeps color and texture.
- Can: Pressure-can low-acid vegetables; water-bath only pickled/acidified ones.
General home-preservation guidance — for tested processing times and safety, follow the National Center for Home Food Preservation.
Growing timeline
Companion planting — with cited sources
From US/Canada cooperative-extension publications and peer-reviewed studies. Evidence-tier dots show how strongly each recommendation is backed: ●●● peer-reviewed mechanism · ●● extension consensus · ● traditional knowledge with a plausible mechanism.
Pairs well with (1)
- Common LettuceEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationpollinator-attract
Chicory's blue flowers support bees and are recommended at bed edges of salad gardens; no specific pest-deterrent claim with empirical support.
Source: University of Maryland Extension
Good predecessors in rotation (1)
- CornEvidence tier B: Extension consensus across multiple US/Canada land-grant institutionssoil-conditioning
Forage chicory is included in cover-crop and pasture-improvement mixes for its deep taproot, which breaks compaction and cycles nutrients. Recommended in Cornell and SARE cover-crop literature ahead of heavy-feeding row crops.
Sources cited
- S18
- SARE (Sustainable Agriculture Research and Education)
- S29
- Cornell Soil Health Lab / Northeast Cover Crop Council (NECCC)
- S9
- University of Maryland Extension — Home & Garden Info Center
Care & troubleshooting— extension-sourced, with citations
When to feed, prune & water
Attract beneficial insects and protect pollinators
Protection- Routine carePlant insectary flowers and tolerate light pestsstrong evidence — extension confidence
Grow a diversity of flowering plants (including small-flowered umbels and asters) to feed predators and parasitoids, and tolerate low pest numbers so natural enemies have prey to stick around.
- Routine careNever spray open bloomsstrong evidence — extension confidence
Avoid insecticides on flowering plants and apply any needed sprays in the evening when pollinators aren't active, and favor selective products over broad-spectrum ones to spare bees and beneficials.
Mulch to suppress weeds and retain moisture
Mulch- Routine careApply organic mulch around plantsstrong evidence — extension confidence
Spread a few inches of straw, shredded leaves, or compost around established plants (keeping it off stems) to hold soil moisture, suppress weeds, and moderate soil temperature; wait until soil has warmed for heat-loving crops.
Protect the garden from rabbits and voles
Protection- Routine careFence out rabbitsstrong evidence — extension confidence
Surround beds with 1-inch mesh chicken wire at least 2 feet tall with the bottom buried or staked down a few inches so rabbits can't push under it.
- Routine careReduce vole habitat and guard stemsstrong evidence — extension confidence
Keep grass and mulch pulled back from plant bases and crowns to remove vole cover, mow surrounding vegetation, and use hardware-cloth guards around vulnerable woody stems before winter.
Clean up debris and sanitize at season end
SanitationUnusual this time of year.
- Routine careRemove spent plants and fallen debrisstrong evidence — extension confidence
Pull and clear old plants, dropped fruit, and leaf litter at season end, since many pests and diseases overwinter in this debris; dispose of diseased material rather than composting it.
- Routine careClean tools, stakes, and cagesmoderate evidence — extension confidence
Wash and sanitize stakes, cages, and tools that touched diseased plants before storing or reusing them to avoid carrying pathogens into next season.
Harden off seedlings
ProtectionUnusual this time of year.
- Routine careGradually expose plants to the outdoors· every 1 days · ~2 wksstrong evidence — extension confidence
Starting about two weeks before transplanting, set seedlings outside in a sheltered, shady spot for a few hours and lengthen their time and sun exposure each day, avoiding windy days, to prevent transplant shock.
- Routine careEase back on water and transplant on a mild daystrong evidence — extension confidence
Water a little less during hardening (without letting plants wilt) to toughen growth, then transplant in late afternoon or on a cool, cloudy, calm day.
Succession-sow quick crops
CareUnusual this time of year.
- Routine careSow small batches on a schedule· every 2 wksstrong evidence — extension confidence
Plant short rows of fast crops like radishes, bush beans, and lettuce every two to three weeks rather than all at once, so you get a steady harvest and one bad weather spell won't ruin the whole planting.
Something looks wrong?
Describe what you see on your radicchioand we'll rank the likely causes — most likely first, least-invasive fix first.
Tomato spotted wilt virus
Virussevere- CulturalRemove infected plants (cannot be cured)strong evidence — extension confidence
There is no cure once a plant is infected, so promptly pull and dispose of symptomatic plants to reduce the virus reservoir that thrips spread to healthy plants.
- CulturalStart clean and control weeds and thripsstrong evidence — extension confidence
Use virus- and thrips-free transplants, choose resistant varieties (Sw-5 tomatoes, Tsw peppers) where available, and control weeds around the garden that harbor both virus and thrips vectors.
White mold (Sclerotinia stem rot)
Diseasesevere- CulturalRemove infected plants (manage, not cure)strong evidence — extension confidence
There's no cure for an infected plant; cut out and bag affected plants including the black sclerotia, and don't compost them, since sclerotia survive years in soil.
- CulturalOpen the canopy and rotatestrong evidence — extension confidence
Space plants widely, control weeds, orient rows to prevailing wind, and avoid overhead watering at bloom to dry the canopy; rotate to non-host crops (corn or other grasses) for several years.
- CulturalWater at the base, not overheadmoderate evidence — extension confidence
Use drip or soaker irrigation to keep foliage and the soil surface drier, which discourages the sclerotia germination and mycelial growth that drive white mold.
Botrytis gray mold
Diseasemoderate- CulturalRemove infected tissue and old blossomsstrong evidence — extension confidence
Prune out moldy leaves, stems, and fruit and clear fallen blossoms and debris where the fungus gets started, disposing of them rather than composting.
- CulturalImprove airflow and reduce leaf wetnessstrong evidence — extension confidence
Space and stake plants for good air movement, water at the base in the morning, and harvest ripe fruit promptly so botrytis has fewer cool, humid, wet surfaces to colonize.
Japanese beetles
Pestmoderate- CulturalHandpick into soapy water· every 1 days · ~4 wksstrong evidence — extension confidence
In early morning when beetles are sluggish, knock them into a bucket of soapy water; daily removal also reduces the scent that draws in more beetles. Skip the lure traps, which tend to attract more beetles than they catch.
- CulturalCover plants past bloommoderate evidence — extension confidence
On crops that have finished flowering and set fruit, drape a row cover or netting to keep beetles off without blocking pollination during bloom.
Leafhoppers & aster yellows
Diseasemoderate- CulturalRemove infected plants and weed reservoirsstrong evidence — extension confidence
Aster yellows can't be cured, so pull and discard plants showing yellowing and witches-broom, and clear nearby weedy hosts that harbor the phytoplasma and its leafhoppers.
- CulturalExclude leafhoppers with row covermoderate evidence — extension confidence
On young susceptible crops, a floating row cover keeps egg-laying leafhoppers off and lowers the chance of aster-yellows spread.
Powdery mildew
Diseasemoderate- CulturalImprove airflow + remove worst leavesstrong evidence — extension confidence
Cut out the most heavily coated leaves and thin for airflow; avoid wetting foliage late in the day.
- OrganicPotassium-bicarbonate or sulfur - label use only· every 1 wk · ~4 wksmoderate evidence — extension confidence
Apply a labeled potassium-bicarbonate or sulfur fungicide weekly per the label. No sulfur within 2 weeks of oil or in high heat.
Root rot from overwatering / poor drainage
Diseasemoderate- CulturalLet soil drain and water lessstrong evidence — extension confidence
Water root rots like Pythium thrive in saturated soil, so cut back watering, let the surface dry between irrigations, and water at the base rather than keeping soil constantly wet.
- CulturalImprove drainage and aerationstrong evidence — extension confidence
Use raised beds, loosen compacted soil, and add organic matter to improve drainage; remove plants that are already rotted since affected roots won't recover.
Slugs & snails
Pestmoderate- CulturalTrap, hand-pick at night, reduce cover· every 2 days · ~3 wksstrong evidence — extension confidence
Pick at night with a flashlight, set shallow beer traps, water in the morning so soil dries by dusk, and clear damp hiding spots.
- OrganicIron-phosphate bait - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence
Scatter a labeled iron-phosphate slug bait sparingly per the label; it's pet- and wildlife-safer than metaldehyde.
Tarnished plant bug / lygus
Pestmoderate- CulturalManage surrounding weedsstrong evidence — extension confidence
Keep broadleaf weeds mowed or removed around the garden, since lygus build up on flowering weeds and move to crops as those weeds dry down; avoid mowing large weedy areas right beside fruiting crops at bloom.
- CulturalVacuum or shake plants to monitor and reduce· every 5 daysmoderate evidence — extension confidence
Tap plants over a light-colored tray to check for nymphs; a handheld vacuum used once or twice weekly can hold low to moderate numbers down on small plantings.
- OrganicTreat nymphs if damage is building· every 1 wkmoderate evidence — extension confidence
For active nymph infestations, azadirachtin or a Beauveria bassiana product can give some control per the label; preserve the parasitic wasps and other natural enemies that help suppress lygus.
Whiteflies
Pestmoderate- CulturalRemove infested leaves and hose off· every 4 daysmoderate evidence — extension confidence
Pick off and discard heavily infested lower leaves and rinse colonies off undersides with a strong spray of water; yellow sticky cards help monitor numbers.
- OrganicApply a labeled soap or oil· every 1 wk · ~3 wksmoderate evidence — extension confidence
Apply a labeled insecticidal soap or neem oil per the label, covering leaf undersides; these reduce but won't eliminate whiteflies, so repeat as needed.
Cutworms
PestmoderateUnusual this time of year.
- CulturalPlace stem collars on transplantsstrong evidence — extension confidence
Push a collar (cardboard tube, can, or cup with bottom removed) a couple inches into the soil around each stem so it extends a few inches above ground; this blocks cutworms from reaching the stem.
- CulturalScout soil and hand-remove· every 3 days · ~2 wksstrong evidence — extension confidence
In the evening or early morning, check the soil around damaged plants and remove curled larvae by hand; tilling beds about two weeks before planting also reduces larvae and pupae.
- OrganicApply a labeled Bt or spinosad· every 1 wk · ~3 wksmoderate evidence — extension confidence
If damage continues, apply a labeled Bacillus thuringiensis (kurstaki) or spinosad product per the label, targeting small larvae; Bt works best on young first- and second-instar cutworms.
Aphids
Pestlow- CulturalBlast off with water· every 3 days · ~2 wksstrong evidence — extension confidence
Knock colonies off with a strong jet of water in the morning; repeat every few days. Light infestations rarely need more.
- OrganicInsecticidal soap - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence
For persistent colonies apply insecticidal soap to undersides per label. Avoid open flowers.
Bolting (premature flowering)
Disorderlow- CulturalShade and harvest before boltingstrong evidence — extension confidence
Once a plant bolts it can't be reversed, so harvest at the first sign of stalk formation; 30-50% shade cloth and steady watering during heat help delay bolting in cool-season crops.
- CulturalUse bolt-resistant varieties and succession sowmoderate evidence — extension confidence
Choose heat-tolerant, slow-bolt varieties and stagger small sowings so a heat spell doesn't take out the whole planting.
Earwigs
Pestlow- CulturalTrap and remove· every 1 days · ~2 wksstrong evidence — extension confidence
Set rolled damp newspaper, low tuna-style cans of oil, or short tubes near plants at dusk, then dump trapped earwigs into soapy water each morning; reduce mulch and damp hiding spots near vulnerable seedlings.
- OrganicApply a bait only if damage persists· every 1 wkmoderate evidence — extension confidence
Established plants usually tolerate earwigs, which also eat aphids; if seedlings are being destroyed, a spinosad-based bait labeled for earwigs can help per the label.
Transplant shock
DisorderlowUnusual this time of year.
- CulturalWater in well and provide shade· every 1 days · ~1 wksstrong evidence — extension confidence
Water transplants in thoroughly at planting and keep the root zone evenly moist for the first week or two, and provide temporary shade during hot, sunny, or windy spells to reduce stress while roots establish.
- CulturalHarden off and plant gently next timestrong evidence — extension confidence
Most plants recover on their own; to prevent recurrence, harden off seedlings before planting, set them out in mild weather or evening, and avoid disturbing the roots when transplanting.