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Lesson:

From Seed to Harvest

Chicory/Radicchio

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Common chicory – Cichorium intybus

Wild chicory – Cicoria selvatica

Chicory, like lettuce and endive, is a member of the dandelion family, Asteraceae. This heritage hints at what is holding it back from being as widely grown as I feel it deserves to be. Most chicory leaves are bitter, but heads of radicchio less so.

Chicory is not well understood as a vegetable, in the UK at least. This lesson is perhaps the most ‘complicated’ of this course, unless you already grow it and are familiar with chicory’s possibilities.

Four striking chicory hearts in late October

Beautiful Treviso and Tardive chicories outside in mid-December

Some sparkling Treviso chicory in a frost on 26th November

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In Italy, where much chicory breeding has happened and continues to happen, there is a liking for bitter leaves and an interest in growing them. Contrast that to the UK where, until recently at least, chicory was barely eaten and even less grown.

Recent breeding has helped, because you can now buy seeds of varieties that grow a reliable head, without forcing. Their radicchio is full of tasty, bittersweet leaves, which also store really well.

Large chicory plants with developing heads can be mistaken for cabbage. It’s a false comparison! For one thing, chicory leaves have fewer holes because they suffer fewer pests compared to brassicas.

The main issue is sowing them at the correct times. Chicory flowers in the spring, so first sowings are made after that time. They do not flower in summer and autumn, except for any premature bolting.

Harvest period

Days from seed to first harvest: 30 for leaf chicory, 75-150 for radicchio, up to 250 for forced chicory.

Chicory seeds sownReady to harvestEarly summerRadicchio in early autumn mostlyJust before midsummerRadicchio in mid to late autumnEarly to midsummerForced chicons mid to late winter

Best climate is with summers not too hot, say afternoons of 21–33 °C/70–91 °F, with occasional rain or storms.

In the UK at least, there is a muddle about exactly what chicory is, which bits you eat, how you may or may not need to force them, and how you process them for eating.

Below we have a look at the possible harvests from the different types.

Among them you will notice some vegetables which are also called or known as endive.
Chicory and endive are closely related – learn more about endive in Lesson 25, Course 3B.

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A bountiful 28 kg/62 lb salad harvest in November, of which 24 kg/53 lb was grown outdoors – about a third of the weight is radicchio leaves

My delicious October salad of radicchio Lusia, chicory, carrot, apple, parsnip, onion, garlic and walnut

Some impressive roasted chicories – sugarloaf are the long pale ones, and Palla Rossa have the dark leaves

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A range of harvests

Wild chicory grows in pastures and hedgerows, has bitter green leaves, and then flowers in its second spring, with pretty blue flowers by early summer.

Leaf chicory is the result of varietal selection for leaves of varied colour, such as Catalogna chicory with long serrated leaves, known as dandelion greens. There is also a large and serrated Catalogna lettuce variety, which grows leaves of a similar appearance that are less bitter.

This lesson is mostly about growing radicchio heads, in order to have chicory harvests with some sweetness to balance the bitter, and for leaves with a firm texture.
If you want to grow leaf chicory, space plants three times as close as for heads, or sow in 15 cm/6 in rows, 5 cm/2 in apart, and pick or cut regularly.
Grow Ingegnoli’s Self-Blanching for less bitter leaves (from Real Seeds).

These leaf chicories, outdoors on 25th March, were transplanted in August – see the distinctive Grumolo Verde on the right

Treviso Tardivo, a chicory for radicchio in autumn and winter, but here shown growing outside in mid-March; it now has a leaf habit, with the colour disappearing fast

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Radicchio is the word for a head of varied colour, shape and density, ideally tight and therefore somewhat blanched and sweeter. The easiest ones to grow are from varieties that automatically fold into tight heads. This happens in autumn, their natural season, and without any forcing process. Heads vary in shape and colour. The two main types are Palla Rossa and Treviso.

Palla Rossa – the best of a varied harvest from Franchi Seeds, variety Marzatica; they were sown in July and this is December

Sugarloaf chicory in mid-October, three months from sowing and not yet making firm heads; harvests were through November until mid-December

Trimmed heads of Treviso in mid-December – these are the reliable 206TT, and have grown outside from a July sowing

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Forced chicory, also called ‘chicon’ and ‘Belgian endive’, is a medium-sized radicchio, from the Witloof variety. It is grown in darkness, thus blanched pale yellow in colour, and is more sweet than bitter.

Chicory root can be eaten. A variety called ‘Chiavari’ Root Chicory is long, thin and white, is best sown in early summer.

Chicory coffee is from roasted roots of Magdeburg chicory, and it continues the bitter theme. After Prussian troops invaded France in 1870, under Bismarck, he went to a café and asked for all the chicory to be brought out, and placed on the table in front of him. Then he asked that they make the coffee!

I like the dry bitterness of some roasted chicory in my coffee, and used to add it to the coffee pot when living in France. In the UK however, it’s not often available in dry form, but sells as liquid ‘Camp Coffee’.

Witloof chicory in September is for forcing – you can see how the roots are enlarging

For forcing – placing one large Witllof root in a pot in late November; it then went into a dark cupboard in the house

1st January – these Treviso have been forced in the house in almost complete darkness

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Is chicory a lettuce?

Chicory is in the lettuce family, along with dandelions. Here are chicory comparisons with lettuce:

Chicory leaves are much higher in dry matter, so they store well.
The season of growth is hugely different because chicory flowers in spring. Therefore its best sowing season is from early summer, and not in the spring.
Leaf texture is shinier compared to lettuce, so the colours are brighter.
Chicory does not suffer root aphid or leaf mildew, both of which make it a stronger plant than lettuce for growing in late summer and autumn.

Six main types of radicchio, and varieties

There are not many named varieties which I recommend, having tried a lot of them! I urge you to be cautious of beautiful photos on seed packets, which may raise your hopes too much.

Rosso di Chioggia

A round, red Palla Rossa (red ball) type, and the best-known chicory outside Italy. I have grown them for decades, with irregular hearting, except when using hybrid seed such as F1 Indigo.

Almost all the Palla Rossa varieties I grew were incredibly variable in the development of heads, with many forming small ones, if at all. The few larger heads then started to rot within ten days.

Then I discovered 506TT* and it was a revelation. Over the last three years I feel confident that every planting will succeed to about 90%, for decent sized heads which stand well. *TT derives from the T&T seed company of Chioggia in the Veneto, NE Italy.

Even 506TT varies a lot – it’s a common trait of chicory that there isn’t much uniformity, even when sown on the same day

See the range of colours in these Palla Rossa 706TT hearts of late chicory radicchio

These freshly harvested chicory radicchio, 506TT and 706TT, still have roots on and can be stored in a tray in the shed for up to a month

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Rosso di Treviso Precoce

A Treviso which matures to a head in the garden before winter, without any need for forcing. For 33 years I barely succeeded with Treviso chicories when I grew the Franchi varieties, for example, a seed company that is family run and based in Italy. They supply the British company Seeds of Italy.

I felt so blessed to then discover 206TT. After 35 years of attempting to grow Treviso chicory, I was actually harvesting beautiful long heads of lovely flavour, with only a little bitterness. They are excellent in the salad mix because of their crunchy texture, and the leaves are not too big. For roasting, they are simply a treat.

Treviso Tardivo

This is more complicated because it involves forcing. Again, I struggled with the Franchi seeds because it is not clear on their packet that this is a forcing chicory. Their photo suggests to me that at least that you can grow lovely heads of Treviso in the field, late in the season.

I discovered on YouTube that they are harvested in late autumn and brought into sheds, where the roots sit on benches with running water around their lower part. New growth is in darkness, so there is a lovely blanched effect to the heads, after much peeling and trimming. To replicate this at home would be difficult! Here I am forcing Verona as an example:

In early December, these Rossa di Verona have been grown for forcing and, despite being sown five months earlier, are providing hardly any harvest of hearts

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Now time for the main event; for forcing – a tray layered with compost, Treviso chicory roots and then more compost on top

Seven weeks later – the Verona roots are looking great; they were in the half-lit shed and are now growing a few too many chicons, which is keeping them at a small size

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Variegato di Castelfranco

Called the Tulip of Winter because of a beautiful leaf formation in its head, Castelfranco heads are slightly loose, helping them to be hardy to frost. The sowing date must be early enough to enable a large enough plant before winter, but not too early. Otherwise, the folded in leaves happen before winter. Later sown plants survive winter weather better, for welcome (though small) heads in cold and dark conditions.

The most dramatic aspect of Castelfranco is their leaf colour, because on the background of pale green there are dashes of vivid orange, yellow and pink. These become more intense towards the centre of any head, like a vivid sunset. They are a warming sight indeed in wintertime.

Variegata da Lusia is a variety of Castelfranco, making tighter heads in autumn rather than early winter. Lusia’s heads mostly do not stand well, before rotting. But they are gorgeous to behold and mild to eat.

Variegata da Lusia heart leaves in mid-December

11th January – this Variegata da Lusia is suffering from frost damage; these were picked four weeks earlier due to bitter weather in December, then stored in a shed

The same plants looked like this after trimming the rotting outer leaves – amazing winter heads, though not heavy

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Rosso di Verona

With this type also, hearts do not form outside in the way shown on seed packets. Through many years of trying, the best result I had was rather insignificant and open heads. They had lovely quality and colour, but in too small an amount to justify the time and space needed.

Verona regrowth outside in late January – the first growth was cleared for a small harvest in December

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Last December I decided to cut off the tops and dig out the roots, to transplant into a tray of compost, not too deep. The tray was in my tin shed, not ideal for forcing because there is some daylight and some frost. See above for a later result too, after another 13 days.

Treviso chicory for forcing – here I’ve just added compost on top of the roots

These forced Rossa di Verona roots were planted in a tray and kept dark in the shed for 29 days beforehand

The same day – these forced Treviso can now be thinned

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Rose del Veneto

This is like a pink sister to Verona, with equally small harvests and intended for forcing. They are even more beautiful for being pink rather than dark red. I would say this and the Verona are not for amateur gardeners, unless you have a lot of spare time and space. In that case, they are fun to grow!

(Information on the above six types is helped by chicoryweek.com.)

Pan di Zucchero/Sugarloaf chicory

This has a drawback – it is very pale in colour. Leaves are perhaps a little papery in texture and less crisp than other radicchios.

Yet the folded-in central leaves are sweet indeed, a real treat in autumn and superb roasted as well. Sow and grow as for all radicchio – heads are large and can weigh over 1 kg/2.2 lb from sowing in late June.

See the variability of heading in these Sugarloaf chicories

The last few Sugarloaf chicories sitting in a December frost

A Sugarloaf chicory head and middle leaves, on 19th December

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Puntarelle (also known as Catalogna de Galatina)

A large plant that is grown for the young, hollow-stemmed flowering shoots, rather than leaves. The shoots develop into dense beautiful buds with many points, like thin broccoli. Upon harvest, they are separated and julienned into thin strips, then soaked in cold water for a few hours to remove some bitterness.

They develop an elegant curl and the texture is crisp – either eat raw or, more commonly, cooked. A delicacy of the Roman region, where it is highly esteemed.

Puntarelle chicory making a shoot in late October – I had transplanted it in early August after a cabbage harvest

Some lovely shoots of Puntarelle chicory, outside on 23rd October

A bowl of elegant Puntarelle chicory after being soaked in icy water

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Suitable for containers/shade?

Chicory grows well in shade, and in containers too. Heads will be smaller because, to achieve a large radicchio, you need a decent amount of large leaves preceding it. Don’t expect a huge harvest, but still a worthwhile one. Especially because you can grow them after, say, a harvest of potato, French beans or lettuce. Chicory for leaves is more worthwhile in containers, as long as you like bitter leaves!

For bitter leaves through winter in the greenhouse, unheated, these are Palla Rossa, Frenzy endive and Castelfranco Salad King

sow & propagate

Transplant - Size, time of year, Spacing, support

water

container growing

Feed

Prune and train plants/thin fruit

Harvest times and method

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How to judge the readiness of radicchio

About ten weeks after sowing, watch for leaves folding in around developing heads. They are less obvious than cabbage, for example, and it’s difficult to know how dense they are just by looking.

Use your fingers to push into heads and feel if they are soft or firm.
Best harvests are when they feel reasonably solid.
If you wait more than two to three weeks after that, there is a risk of some decay on heads’ outer leaves.

How to pick

This depends on what you hope for after harvesting the head.

An option is to leave roots in the ground, for secondary harvests of much smaller heads. They are side shoots that grow out of the main stem. Simply cut just below head level for your radicchio, and trim off outer leaves until you have a nice head. Next, at ground level, remove any decaying lower leaves, so that within one or two months you will see new but small shoots. They keep appearing until spring, depending on your climate.
When your aim is to clear the ground, harvest by grasping a plant with both hands, outer leaves and all. Gently rotate it, with a slight pull. This removes just the central cluster of larger roots and leaves most in the soil. Trim those roots and the outer leaves to find your radicchio.

Roots to force

Use a sharp spade pushed vertically down and close to the main root, then lever while pulling on the root’s shoulder. Do this in late autumn to early winter, before frosts colder than about –6 °C/21 °F.

Place the roots in pots or trays, with only enough compost that they stay moist. Use any tray and pack them in, at 15–20 cm/6–8 in apart – the closer spacing is for smaller roots.

Storing

Firm heads store well. Be sure there are no rotting leaves on the outside, and place them in boxes or crates to keep anywhere cool and damp. In my brick shed, with temperatures -1–10 °C/30–50 °F through winter, they store for up to six weeks.

Before eating them, you need to trim off a few decaying outer leaves. Slow growth continues in stored heads, with their central stem elongating as it moves towards flowering. So the number of usable leaves decreases all the time.

Saving seed

I have not tried this yet but I want to. I have not found information about how many plants you need for pollination to be successful. In 2020 I succeeded with just one plant of endive (a close relative of chicory), with subsequent growth through winter being strong and even.

This suggests there was no inbreeding from only one plant producing the seed, which is the case with lettuce. I think that chicory may be the same.

See more on Real Seeds UK website.

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Potential problems

Clear

See ‘How to pick’ above. The main point is that any stem with its root system left in the soil will usually survive winter while growing more small chicory leaves, and then develop flower stems through spring. It’s fine to leave many small roots in the soil.

Follow with

Harvests are in autumn and there is usually not time to follow with new plantings. My normal process after plantings is to mulch beds with compost for the year ahead.

Variations could be to sow or transplant broad beans and garlic.

Or, after earlier harvests of chicory sown by mid-June, there is time (just) either to transplant autumn salads, or to sow a cover crop.

In 2020 I compared sowings on 1st October of buckwheat (Fagopyrum esculentum) and white mustard (Synapsis alba).

The buckwheat barely grew before it was killed by a slight frost in early November. Clearly it needs sowing earlier, by mid-September at the latest. What I had read about its sowing dates was unclear.
Meanwhile the mustard grew strongly, and we even took several harvests from its tops for salad leaves, from late October through November. Then it was killed by -5 °C/23 °F frosts by mid-January.