How to Grow Chicory from Seed (Cichorium intybus): Radicchio, Sugarloaf & Forcing Witloof

Chicory has the most confusing name in the vegetable garden and, once you see past it, one of the most useful habits: it is at its best exactly when everything else is finishing. Radicchio colours up with the first frosts, sugarloaf stands in the bed until December, and witloof — the pale, tight chicons the Dutch and Belgians grow in the dark — is a crop you harvest indoors in January from roots you lifted in November. All of them are the same species, Cichorium intybus, a perennial of European roadsides with sky-blue flowers, and all of them come from a sowing made between late spring and late summer. The trick is knowing which type is in the packet, because the four groups want different dates and give you four entirely different vegetables.

• Sow Mid-May–mid-Jun (witloof for forcing) · Jun–early Aug (radicchio & sugarloaf) · Mar–Sep (leaf chicory) · Aug–Oct (Grumolo)
• Depth & space 1 cm deep · rows 30 cm · thin to 15 cm (witloof) or 25–30 cm (heading types)
• Hardiness Sugarloaf and Grumolo to around −8 °C · early radicchio frost-sensitive · witloof roots lifted before hard frost
• Harvest Sep–Dec from the bed · forced chicons Nov–Mar, 3–4 weeks after boxing the roots

One species, four vegetables — and a naming muddle

Start with the names, because they trip everyone up. Endive — the frilly frisée and the broad-leaved escarole — is a different species, Cichorium endivia: an annual, milder and nowhere near as hardy, which you will find under endive or Cichorium endivia. What the British call chicory and the Americans call Belgian endive is the forced chicon of C. intybus; what the Italians call radicchio is the red-heading form of the same plant; and the roasted root that once stretched wartime coffee is the same species again. The whole chicory collection — and its botanical twin, Cichorium intybus — sorts into four groups.

Witloof, or Brussels chicory, is grown for its root. You sow in early summer, lift the roots in autumn and force them in darkness to produce compact white chicons: Zoom F1, Brussels and Videna in our range, plus an organic Brussels. Radicchio is the red one — round Palla Rossa and Chioggia, the elongated Treviso, the late Rossa di Verona, and the speckled cream-and-crimson Castelfranco and Variegata di Lusia, all grouped under radicchio. Sugarloaf (Pain de Sucre, Zuckerhut) forms a tall, pale, self-blanching head like an overgrown cos lettuce and is the hardiest and most productive of the heading types. And leaf chicory — the Italian cutting types such as Catalogna, Spadona, Barba di Cappuccino and Zuccherina di Trieste, plus the winter-hardy Grumolo — is sown thickly and cut young, in the same way as winter salad leaves.

When to sow: the chicory calendar runs backwards

Most vegetables are sown as early as you dare. Chicory is the opposite: the types that take longest to reach the plate are sown first, and sowing too early is the classic mistake. A witloof root started in April sits through the cold nights of spring and bolts in July, giving you a flower stem instead of a fat root, so the forcing types go in from mid-May to mid-June and no sooner. Radicchio and sugarloaf follow from June to early August — heads formed in the shortening days of September and October are firmer and far less bitter than any summer attempt. Leaf types can be sown from March to September and cut within six weeks, and Grumolo, sown in August or September, overwinters as a flat green rosette and hearts up in March.

Which leaves the honest September question. It is too late this year to sow witloof, radicchio or sugarloaf for full-sized heads — they need four to five months. It is not too late for a band of cut-and-come-again chicory (Zuccherina di Trieste and the plain cutting type are both listed for September) or for Grumolo, and a late-sown Castelfranco or Treviso under a cloche will give small, sweet hearts in early spring rather than autumn. Everything else goes on the list for next May and June — see the seeds to sow in June collection — while this month's sowings are in the September sowing guide and the seeds to sow this month collection.

How to sow chicory, step by step

1. Choose the bed for the root, not the leaf Witloof wants deep, stone-free soil that was manured for a previous crop — never fresh compost, which forks the roots exactly as it does with carrots. Radicchio and sugarloaf are less fussy but hate a waterlogged winter bed. See preparing your soil.
2. Sow direct, 1 cm deep, rows 30 cm apart Chicory has a taproot and resents disturbance. Direct sowing into a moist drill germinates in 7–14 days at 15–20 °C. If slugs make that hopeless, sow in modules and plant out within three weeks, before the root reaches the bottom of the cell.
3. Thin hard and early 15 cm between witloof plants gives roots with the ideal 3–5 cm crown; 25–30 cm for radicchio and sugarloaf. Crowded plants make thin roots and loose heads, and neither forces or hearts properly.
4. Water evenly, feed not at all A dry August followed by heavy rain splits heads and triggers bolting, so steady moisture is the aim — see watering your garden. Nitrogen makes leafy, bitter, floppy plants; chicory needs none.
5. Lift witloof roots after the first frosts Late October or November, once the leaves have collapsed. Trim the leaves to 2–3 cm above the crown, cut the root tip to leave 15–20 cm, discard anything thinner than a thumb, and store the roots in damp sand in a cool shed until you are ready to force them.

Forcing witloof: chicons in the dark

This is the part that makes chicory worth a whole article. Stand five or six trimmed roots upright in a deep pot or bucket of moist compost or sand, crowns just showing, and cover them with an upturned pot of the same size with the drainage holes blocked. The darkness must be complete, because any light turns the chicon green and bitter. Keep them at 10–15 °C — an unheated spare room, a cellar or the cupboard under the stairs is ideal; a warm kitchen gives loose, leggy heads — and keep the compost just damp. In three to four weeks the chicons are 10–15 cm tall and tight; snap them off at the crown before the tips begin to open. Most roots give a second, smaller flush. Start a new bucket every fortnight from November and the supply runs to March.

The old method — a trench outdoors with 15 cm of soil heaped over the crowns — still works, and in a mild winter the roots can even be left where they grew and forced in place under an upturned bucket. Indoors is simply more reliable, and it turns a windowless cupboard into the most productive corner of the January garden.

Both routes fit the same bed in the same year if you plan it: a row of witloof at the end of May, a row of Palla Rossa in early July, a band of cutting chicory in September and Grumolo to take over the space in spring. That is succession sowing with one packet a month, and it means chicory on the table from September until the following April.

Care, bitterness and the cold

Chicory is one of the least demanding crops in the vegetable garden: no feeding, no staking, no pests worth a spray. Slugs are the exception, at the seedling stage and inside the crowns of forced chicons, and a barrier or an evening patrol does more than anything from a bottle — see garden pests and control. Aphids sometimes colonise the hearts in a warm September, and lettuce root aphid can weaken plants on the same ground two years running, so keep chicory moving in the crop rotation and treat it as a leaf crop rather than a root.

The bitterness is a plant chemical, lactucopicrin — the same compound that makes bolted lettuce unpalatable — and there are three ways to tame it. Darkness is the first: a forced chicon and the pale heart of a sugarloaf are mild precisely because they never saw the sun. Cold is the second: a run of frosty nights converts starch to sugar and deepens the red of a radicchio at the same time, which is why a November Treviso tastes nothing like an August one. The kitchen is the third — half an hour in cold water, a hot grill, and a dressing with fat and something sweet. Growers in the Veneto go further and blanch the late Treviso and Verona types in tanks of running spring water for a fortnight, but frost and a bucket do the job at home.

Harvesting: heads, stumps and puntarelle

Radicchio is ready when the head feels firm under gentle pressure — eight to twelve weeks from sowing for the early types, longer for the late ones — and is cut at the base with a knife. Leave the stump in the ground: the late types especially produce a flush of small secondary heads, and Rossa di Verona will overwinter and crop again in spring. Sugarloaf can stay in the bed until a hard frost threatens, then come indoors whole to a cool shed, where the heads keep for several weeks. Cut the leaf types 3 cm above the crown, as you would any salad leaf. And if you let a Catalogna plant stand over winter, the hollow shoots it throws up in March are puntarelle — the Roman delicacy, sliced into curls in iced water and dressed with anchovy. All of it keeps badly once cut, so pick as you need it; our guide to harvesting and storing produce covers the rest of the winter kitchen.

Common chicory mistakes

• Sowing forcing types too early — an April sowing bolts in July. Mid-May to mid-June, and not before.
• Fresh manure under witloof — forked, branching roots that will not force. Use ground manured for the previous crop.
• Forcing in light or in warmth — a chink of light turns the chicon green and bitter; a warm kitchen gives loose heads. Complete dark, and 10–15 °C.
• Treating it like lettuce — chicory wants no feed and a leaner soil. Nitrogen means leaves, not hearts.
• Cutting radicchio before the cold — the colour and the sweetness are made by frost. A September head is a pale, bitter shadow of a November one.
• Pulling up the stump — leave it; the second flush of small heads is often the sweetest of the year.

Frequently asked questions

Is chicory the same as endive?
No, though the names are used interchangeably across Europe. Chicory is Cichorium intybus — witloof, radicchio, sugarloaf and the cutting types. Endive is Cichorium endivia, the frisée and escarole group: an annual, milder, sown in summer and far less tolerant of frost. The forced white chicon that Americans call Belgian endive is, confusingly, chicory. Both are grown in much the same way, but only C. intybus has the fat taproot that can be forced.

Can I sow chicory in September?
Only the fast leaf types and Grumolo. Cut-and-come-again chicory sown now gives young leaves within six weeks and, under a cloche, keeps producing into winter; Grumolo sown in September sits as a rosette and hearts up in March. Witloof, radicchio and sugarloaf need four to five months and a summer sowing, so those go on next year's list. A cold frame or cloche, as described in extending the growing season, turns a marginal late sowing into a reliable one.

Why is my chicory so bitter?
Usually because it was harvested in warmth and in light. Heads cut in August or early September, before any cold nights, are at their most bitter; forced chicons exposed to even a little light turn green and sharp; and a plant that dried out and then bolted is bitter through and through. Wait for frost, keep the forcing pot properly dark, soak the cut leaves in cold water, and choose the naturally milder types — sugarloaf, Castelfranco and Grumolo — if you find the rest too strong.

Will radicchio and sugarloaf survive frost?
Sugarloaf and Grumolo take around −8 °C in their stride, and the late radicchio types — Treviso, Rossa di Verona, Castelfranco — need a few frosts to colour and sweeten, though a hard freeze below about −5 °C damages the outer leaves. The early Palla Rossa types are the frost-sensitive ones and should be cut before the first hard frost. Fleece over the bed buys another month for all of them.

Chicory asks for a sowing in early summer and a bucket in a dark cupboard in November, and in return it fills the gap between the last lettuce and the first spring leaves. If you are in the garden this week anyway, the other September job is bringing in the herbs — our guide to harvesting and drying herbs covers what to cut before the frost. Browse the full vegetable seed range and the organic vegetables, or start with our beginner's guide to growing vegetables and the rest of our growing guides.