Radicchio
Cichorium intybus
Asteraceae · sunflower family
Origin · Mediterranean · temperate Europe · Western Asia
- Matures
- 3 months
- Harvest
- Once · Annual
- Sun
- 6–8+ hrs
- Spacing
- 8–12 in
Planting window
When to sow, by microclimate — foggier blocks run a different calendar than sunnier ones.
| Jan | Feb | Mar | Apr | May | Jun | |
|---|---|---|---|---|---|---|
| Foggy | ◐ | ● | ● | ◐ | ◐ | |
| Sunny | ◐ | ◐ | ◐ |
| Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|
| Foggy | ● | ● | ● | ◐ | ◐ | |
| Sunny | ● | ● | ● | ◐ | ◐ |
Sunlight
How well it does at each level of direct sun per day.
Soil depth
Root room it needs — useful for sizing raised beds and containers.
Soil pH
The soil acidity it grows best in — most crops sit just below neutral, so this mostly matters for heavily amended or long-reused beds.
- Preferred range
- pH 6.0–7.5
Spacing
Room each plant needs — along the row and between rows — for sizing beds.
- In-row
- 8–12 in
- Between rows
- 18 in
Growth habit
The shape it makes in the bed and how tall it gets — what tells you whether to give it a trellis, a stake, or just room.
- Habit
- Low mound
- Mature height
- 6–12 in
Low and self-supporting — no staking needed.
Growing in containers
Whether it does well in a pot, planter, or window box — the SF balcony-and-deck question, weighing its footprint, form, and staying power, not just root depth.
Happy in a pot, planter, or window box — no garden bed required.
How to start it
Sow it where it grows, or raise it under cover and set it out — and how far ahead to start the seedlings if it's the latter.
- Usually
- Direct-sow
Sown straight into the bed it will grow in.
Getting started
How it goes in the ground — how deep to sow or set it, and the soil temperature it needs to wake up. The cold-soil floor is the real limiter for direct-sowing in a foggy SF spring.
- Started from
- From seed
- Ideal soil temp
- 70–75°F
- Sow depth
- 0.25 in
- Time to emerge
- 7–10 days
Germinates between 45–85°F; happiest around 70–75°F.
Watering & feeding
How thirsty and how hungry it is — the water it wants and how much feeding the bed needs to keep it producing. In the fog belt even a thirsty crop drinks less than it would inland.
- Water need
- Moderate
- Feeding
- Moderate feeder
Wants steady, even moisture — roughly an inch a week, a little more in a heat spell.
A balanced feed worked into the bed at planting usually carries it through the season.
Keep uniformly moist — drought slows the head and turns it bitter. A moderate feeder.
Pests & diseases
What tends to trouble this crop — what it is, what you'll see, and what to do about it, least-toxic first.
Pests2
Aphids
- What it is
- Aphids have soft pear-shaped bodies with long legs and antennae and may be green, yellow, brown, red, or black depending on the species and the plants they feed on. A few species appear waxy or woolly due to the secretion of a waxy white or gray substance over their body surface.
- What you'll see
- Low to moderate numbers of leaf-feeding aphids aren't usually damaging in gardens or on trees. However, large populations can turn leaves yellow and stunt shoots; aphids can also produce large quantities of a sticky exudate known as honeydew, which often turns black with the growth of a sooty mold fungus.
- What to do
- Before planting vegetables, check surrounding areas for sources of aphids and remove these sources. On the other hand, these aphid-infested weeds can sometimes provide an early source of aphid natural enemies.
Worms and Loopers
- What you'll see
- Light to dark green insects that chew holes and hide in leaves. Adult loopers are gray or brown moths while cabbage worms are white butterflies.
- What to do
- Control worms and loopers with appropriate insecticides or biological measures.
Diseases2
Fungal Root Rots
- What you'll see
- Wilting and reduced plant vigor which occurs during forcing.
- What to do
- Cultural practices that facilitate air movement will reduce disease severity.
Viruses
- What you'll see
- Stunting of growth. Interveinal yellowing and brittleness in older and lower leaves.
- What to do
- Control aphids which transmit the disease.
Harvest & storage
How to tell it's ready to pick, and how to keep it once it's in.
- Keeps
- WeeksHolds a week or two in the fridge.
- Ready to harvest
- Cut the firm head at the base once it has hearted up; the flavour is best in cool weather, milder young.
- Storing
- Refrigerate the head in the crisper; it keeps a week or two.
Culinary use & nutrition
What it's for in the kitchen, and the nutrients a 100 g raw serving is a notable source of.
In the kitchen
- Raw
- Boiled / steamed
Nutrition highlights
- Excellent source
- Vitamin K, Copper
- Good source
- Vitamin E, Folate
Share of the Daily Value in a 100 g raw serving (USDA FoodData Central).
Pollinators & wildlife
What this crop offers the garden's wildlife once it flowers — often the payoff for letting a bolting plant stand.
- Bees
- Honeybees and natives — bumble, mason, and sweat bees — working the flowers for pollen and nectar.
- Butterflies
- Adult butterflies nectaring, and in some crops the leaves their caterpillars grow up on.
Only from a bolted or second-year plant — a head cut on time never flowers. Left to run up, it is common chicory, and the sky-blue daisies it opens each morning are nectared at by both bees and butterflies.
Sources
Growing data on this page is drawn from Utah State University Extension, Cornell University Home Gardening, and the other references on our sources page.