- Radicchio: origin and characteristics
- Radicchio varieties
- Buy radicchio plants: you should pay attention to this
- Growing and planting radicchio
- Caring for radicchio: the right watering and fertilizing
- Propagating radicchio
- Harvesting and storing radicchio
- Radicchio: ingredients and use
- Radicchio: diseases and pests
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The Italian salad with the bitter note is very popular and extremely he althy. We show what you should consider when growing radicchio.
Radicchio (Cichorium intybus var. foliosum) is a popular vegetable from Italy that we mainly enjoy in a salad. However, the cultivation of red leafy vegetables differs from normal lettuce because they are sensitive to low temperatures in the germination stage. Nevertheless, it is possible to grow the Italian delicacy with us. We'll tell you what you need to know so that radicchio can also thrive in your garden. In this article you will learn everything about the origin, suitable varieties, cultivation, care, harvesting and use of red lettuce.
Garden lettuce belongs either to the lettuce genus (Lactuca) or to chicory (Cichorium). The radicchio counts together with chicory (Cichorium intybus var. foliosum), endive (Cichorium endivia) and Sugar Loaf (Cichorium intybus var. foliosum f. cylindricum) to the genus Chicory. Together with chicory, radicchio forms the special subspecies Cichorium intybus var. foliosum. Typical of these is the bitter taste caused by the bitter substance lactucopicrin. Radicchio is also known as red chicory or red chicory.
For a long time it was only grown in Italy and imported to countries north of the Alps. In the meantime, breeding has succeeded in producing new varieties that can also grow in a cooler climate. The red leaves not only bring color to our plates, but also beautify our vegetable beds in the garden with their bright red heads of lettuce. Although radicchio is mostly used in Germany to spice up other leaf salads, it can also be enjoyed fried or steamed. Thanks to its bitter substances and other ingredients, it is very valuable for nutrition.
Radicchio: origin and characteristics
The origin of themost radicchio varieties is in the north of Italy, where the most diverse plants of the genus thrive particularly well. For a long time, radicchio was only grown there. Since about 1985, however, cultivation north of Italy has also been possible. Nevertheless, the largest growing area for radicchio is still in Bella Italia, especially around the towns of Chioggia and Treviso, which even gave their name to two of the most important radicchio varieties. But nowadays radicchio is also cultivated on a large scale in Spain and France.
In the past, radicchio was mainly grown as a biennial plant - today, however, it is usually only cultivated as an annual. It forms a strong taproot and, depending on the variety, develops a more or less thick rosette of leaves with a firm or loose head of lettuce. It also depends on the variety whether the radicchio grows roundish or elongated. The leaves of the lettuce can be classic red with white mottling, completely red, green or yellowish. Radicchio is generally preferred in our latitudes and not sown directly outdoors, as this reduces the risk of flowering without a head forming.
Radicchio varieties
There are many types of radicchio in northern Italy. Some are of protected origin and may only be sold under the variety name if the cultivation has taken place in the corresponding region. In Italy, a distinction is made between two types: Type A is sown from spring to summer and harvested in autumn. Type B is sown from late summer to autumn and has limited winter hardiness. This type can be overwintered in Germany in wine-growing regions, in foil tunnels or under fleece. The numerous radicchio varieties differ mainly in their colour, shape and harvest time. Below we have listed some well-known varieties for you.
Round Radicchio
- 'Rosso di Chioggia': This variety forms the round, dark red heads typical of radicchio with white-ribbed leaves. It is also well suited for cultivation in northern Germany.
- ‘Indigo’: This variety also impresses with a rounded head shape and dark red, white-ribbed foliage.
- ‘Palla Rossa’: This variety forms round, small heads that glow an appetizing red with white leaf veins.
- 'Orchidea Rossa': This radicchio variety has bright red leaves. The head is loosely open.
Elongated Radicchio
- 'Di Trevisio': The growth of this variety is rather unusual because itis particularly tall. In addition, it has good resistance to cold and bears white-ribbed, dark red leaves.
- 'Granato': This variety has an elongated head shape and deep red leaves with white veins. It is ideal for dipping sauces, creams and also for topping and decorating bread.
Colourful Radicchio
- ‘Galileo’: Yellow to light green radicchio; this variety has special pink-red spots to offer. It is also characterized by its fine, mild taste and is highly recommended for salads.
- 'Variegata di Lusia': Solid light green heads; the taste is delicate and mild.
- ‘Rosalba’: This variety has light pink colored leaves and is rather rare.
- 'Der Gelbe von Trieste': This variety impresses with yellow-green, round-oval leaves that have a mild taste.
- ‘Cicorino verde’: This radicchio variety has green leaves.
Radicchio Variegata di Castelfranco: A special delicacy
The 'Variegata di Castelfranco' variety with the peculiar shape comes from the municipality of Castelfranco Veneto in north-eastern Italy. Italians appreciate the speci alty because of its mild aroma and good taste. The variety also differs from the classic radicchio in terms of appearance, as its shape is more similar to that of the typical lettuce. The leaves of 'Variegata di Castelfranco' are light yellow with red splashes of color - this may have given the variety its nickname "Orchid Salad".
But not only its appearance is attractive: 'Variegata di Castelfranco' is rich in vitamins and, according to nutrition experts, should have a positive effect on digestion and blood formation. Since the demand is currently very high, this also explains the exorbitant price of up to 15 euros per head of lettuce. In Italy, too, local traders charge a whopping 12 euros for the salad.
Buy radicchio plants: you should pay attention to this
When buying radicchio for your garden, you should consider whether you prefer to grow the young plants yourself or whether you want to buy them in stores. Growing your own radicchio is not that easy and requires a certain amount of sensitivity so that you don't just find blooming heads of lettuce in the bed later on. However, early young plants are more expensive to buy than radicchio seeds.
Whether you choose to buy seedsor seedling, in any case you should pay attention to the choice of the right variety. Because not every variety is suitable for cultivation in our climate zone. The variety also determines the color and shape of the leaves. Further criteria when buying young plants should be optimal he alth and a vital impression of the little plants: You should not buy very soft, limp, yellowish or very long ("overgrown") young plants. When buying seeds, you should pay attention to the expiry date or the year the seeds were produced. Radicchio seed has a shelf life of 5 - 6 years, but germination capacity decreases every year.
What should you look out for when buying radicchio?
- Selection of varieties: Only select varieties that are suitable for the location.
- Young plants: Only buy firm, well-colored, short radicchio young plants.
- Seeds: Note the shelf life or year of bottling.
You can find radicchio seeds and young plants in garden centres, nurseries and at the weekly market. You will also find what you are looking for on the Internet. The online seed retailer italian-samen.de offers a large selection of different varieties. Radicchio young plants that have already been grown can be obtained online, for example at Dehner.de.
Growing and planting radicchio
Especially when young, radicchio is particularly sensitive and needs optimal conditions in order to be able to grow. In the next section we will tell you what to look out for when growing radicchio, when it is best to sow and plant the lettuce and how to do it correctly. For even more information, check out our lettuce growing overview article.
When to grow radicchio?
The cultivation of radicchio takes place from sowing to the last harvest between mid-March and early winter. Grow indoors or protected under glass between mid-March and late May. The early varieties sowed in mid-March are planted out under protection from the beginning of June. At the end of June, the young plants sown in April are brought outside. The late radicchio varieties sown after the end of May can be planted out from July to the beginning of August.
Tip: Bolting, i.e. the termination of head formation and the emergence of the inflorescence, are promoted equally by cool temperatures and the length of the day. This means radicchio that is planted out early is in cool yearsalways at risk of bolting and must be covered to keep the plants warm and to shield them from the light. Late planted radicchio are less likely to shoot as late summer is usually consistently warm and day length decreases again.
Summary: When to grow radicchio?
- Early varieties between March and July, Late varieties between May and September/November until winter.
- Early varieties: prefer from mid-March, plant out from the end of June, under glass or plastic from the beginning of June.
- Late varieties: prefer from the end of May, plant out from July to the beginning of August.
Where to plant radicchio?
Radicchio is best cultivated in a sunny to partially shaded location. However, blazing midday sun should be avoided. As usual from his native Italy, he also likes it as warm as possible. A loose, deep soil is optimal for the radicchio. This allows the deep taproot of the plant to spread well. Radicchio does not tolerate waterlogging well, it tends to rot in soil that is too wet. In addition, the soil should be rich in nutrients, humic and slightly acidic. The radicchio is a weak feeder, so it does not tolerate heavy fertilization. Very lean soils can be enriched with a mainly organic long-acting fertilizer, such as our Plantura organic tomato fertilizer - these only release nutrients slowly so that oversupply does not occur.
The ideal location and soil for growing radicchio:
- Sunny to semi-shady
- As warm as possible
- Loose, deep, humus-rich soil without waterlogging
- Improve very poor soils with slow release organic fertilizer
Tip: Good neighbors in radicchio beds are beans (Phaseolus vulgaris), dill (Anethum graveolens ), fennel (Foeniculum vulgare) or onion (Allium cepa). Parsley (Petroselium crispum ssp. crispum), radishes (Raphanus sativus var. sativus) or Celery (Apium graveolens).
How do you grow radicchio?
When growing radicchio, sowing is a critical step, because young radicchio is particularly sensitive to cold. We therefore recommend sowing in the greenhouse or at home on the windowsill. Prepare the potty for thislow-nutrient potting soil, our peat-free Plantura organic herb and seed soil is a good choice, for example. Two to three seeds are then placed in these at a depth of one to two centimeters and only lightly sprinkled with soil and everything is well moistened. Now make sure that the temperature in the room never falls below 17 °C - temperatures around 22 °C are better. In a light location without direct sunlight, the seeds should sprout within ten to fourteen days. Once the seedlings have formed the first real leaves after the cotyledons, the plantlets are transplanted into larger pots. Select only the he althiest and strongest plants for this.
Summary: How to Prep Radicchio?
- Prepare pots with potting soil
- Seed placement at a depth of 1 - 2 cm
- Cover only lightly with soil
- Wet
- Put on plastic bag or put in mini greenhouse
- Put in a bright place
- Germination temperature: 20 - 25 °C
- Germination period: 10 - 14 days
- Prick out when the first true leaves appear
As soon as the temperatures outside remain constantly above 17 °C, the early young plants can be planted out in the bed. Loosen normal garden soil superficially. Only heavy soil should be dug deeper. Weeds and stones should be removed from the soil. Our Plantura organic tomato fertilizer ensures a good nutrient supply in the soil on very nutrient-poor soils and contributes to the formation of humus thanks to its mostly organic ingredients.
Now plant in rows 30 centimeters apart. Now prepare planting holes every 25 to 30 centimeters in the rows. These should only be as deep as the radicchio plants were in the pots. Now you can put the plants in the planting holes and fill the holes with soil. Finally everything is poured on well.
Tip: How about combining radicchio cultivation with inter-row planting? This allows you to make optimal use of the space and protects the floor. For example, stick onions or sow dill. Both grow more upright and will not hinder your radicchio.
Planting radicchio outdoors:
- Flatly loosening the bed, digging up heavy soil deeper
- Removing stones and weeds
- Improve very nutrient-poor soils with primarily organic fertilizers
- Row spacing: 30 cm
- Planting distance: 25 - 30 cm
- Plants only as deep as they were in the pot
- Water well
- Optional: Plant or sow good bed neighbors such as dill or onion between the rows
Tip: Be extra careful when releasing the seedlings from the pots. Radicchio forms long taproots that should not be damaged.
Caring for radicchio: the right watering and fertilizing
During the growth phase, radicchio does not tolerate drought well and should therefore be watered sufficiently in midsummer. If your radicchio was already fertilized when planting with an organic fertilizer with a long-term effect, such as our Plantura organic tomato fertiliser, further fertilizer applications are no longer necessary during the cultivation period.
What is the best way to fertilize and water radicchio?
- Basic fertilization with Plantura organic tomato fertilizer at planting
- Water sufficiently and regularly
Tip: Over-fertilizing red lettuce can lead to rotting heads. Burnt leaf edges on lettuce can be a sign of over-fertilization with nitrogen. It is therefore better not to use mineral fertilizers, but rather a predominantly organic fertilizer.
Propagating radicchio
If you want to get your own seeds from radicchio plants, you have to wait until next year. Only then do the plants form one to two meter high inflorescences with beautiful, light blue flowers. In order to be able to enjoy this splendor of flowers and the seeds that later develop from them, you must overwinter your radicchio plant well. It is best to protect them from the cold with a fleece or straw.
When the flowers have withered, remove the buds completely and dry them upside down in a warm place. Once dry, the seeds can then be easily removed and stored in a cool, dark and dry place. You can then use the seeds next year.
How to propagate radicchio?
- Winter lettuce plants: protect from frost with fleece or straw
- The radicchio flowers in the second year
- Let flowers wilt, cut off inflorescences completely and leave to dry upside down
- Remove seeds
- Store in a cool, dark and dry place
Harvesting and storing radicchio
Radicchio is a typical autumn and winter salad. This is partly due to the fact that the typical reddish coloring of the radicchio only develops when there are strong temperature fluctuations between day and night. We therefore recommend not harvesting the lettuce heads until October and November. Then you can really enjoy the rich, red lettuce leaves.
Tip: If you are expecting an early frost, you can cover non-hardy radicchio varieties with foil or fleece so that they are not damaged if it is too cold before harvest take.
Radicchio cultivation takes a relatively long time, so the lettuce can only be harvested about ten to twelve weeks after germination. To harvest, use a sharp knife and cut off the head above the ground. Alternatively, you can just pluck off individual leaves, so the whole lettuce stays fresh longer on the bed. But even when harvested, radicchio can be stored for a long time. You can store the fresh, red lettuce in the refrigerator for up to four weeks. If you want to store the lettuce for longer, we recommend harvesting it with the roots. The lettuce will keep for several months in a cool, dry place, such as a cellar.
How is radicchio harvested and stored?
- For a rich red colour, harvest from October onwards
- First harvest 10 - 12 weeks after germination
- Use sharp knife to harvest
- Cut the head of lettuce just above the ground
- Alternatively, just pick off a few leaves and harvest again and again
- Harvested radicchio stays fresh in the fridge for up to 4 weeks
- Harvested with roots, the lettuce lasts for several months
Radicchio: ingredients and use
Radicchio is not only appreciated for its bitter taste, but is also very low in calories and full of good ingredients.
100 grams of raw radicchio contain:
- 10 kcal
- 0.2 g fat
- 1.5 g carbohydrates
- 1.5 g fiber
- 240 mg Potassium
- 1.5 mg iron
- 28 mg Vitamin C
The bitter substances in the leaves have a digestive and appetizing effect. Because the leaves contain plenty of inulin, which is digested by the body like fiber and stimulates digestion. Radicchio not only spices up salad dishes visually, but can also be used elsewhere in the kitchen.In German-speaking countries, radicchio is mainly used in salads. However, Italians also appreciate the plant as a grilled accompaniment to meat and in pasta or risotto. During the war, a kind of coffee substitute was also made from radicchio and other chicory plants. The bitter taste should be reminiscent of the tart notes of the roasted coffee beans.
Today, radicchio is considered a delicacy. If you don't appreciate its bitter note, combine it with sweet fruit in a salad, such as oranges or pears, or soak it briefly in lukewarm water. If you then remove the leaf veins, it tastes much less bitter. Long radicchio varieties are best suited for cooking.
Radicchio: diseases and pests
In general, radicchio is considered to be robust and easy to cultivate. Occasionally, however, aphids (Sternorrhyncha) can infest the plant. Biological plant protection should definitely be used here. Leaf burn can also occur in nitrogen-rich soils or over-fertilization. Rotting of the leaf heads is also a sign of over-fertilization. Young plants in particular should be protected from slugs (Arion lusitanicus).
Anyone who likes to grow vegetables usually also values gentle and sustainable gardening. In our appropriate special article, we explain which home remedies against aphids will really help you.