How to Grow Radicchio

growing radicchio

Story at-a-glance -

  • Vegetables are a cornerstone to any nutritional plan, helping to provide you with essential vitamins, minerals and health-boosting compounds
  • Radicchio grows best in cooler climates in well-drained and composted soil, including containers; when the weather cooperates you may be able to harvest twice from one plant
  • Radicchio is a nutritional powerhouse and a tasty addition to salads, stews, soups and even omelets; the vegetable holds up well when sautéed, grilled or baked and lends a slightly spicy-bitter flavor to your salad
  • The vegetable has been part of a Mediterranean diet for centuries, with at least five varieties available in the U.S., all named for the regions of Italy where they were first propagated

By Dr. Mercola

High in fiber and containing a good deal of the vitamins and minerals your body requires, vegetables are a cornerstone to any nutritional plan. Nearly 23 percent of Americans report eating less than one fruit or vegetable each day with a median intake of just 1.6 times per day overall.1 By contrast, experts recommend at least five to nine servings of vegetables and fruits each day for optimal health.

Chances are you know vegetables are good for you and may even have been meaning to include more of them in your daily diet. A study finds people who consume seven or more portions of vegetables and fruit a day have a 42 percent lower risk of dying from any cause, compared to those who ate less than one portion, and vegetables have the greatest impact.2

Vegetables can be eaten raw, lightly steamed or cooked, juiced, added to stews and soups, and even fermented. If you'd like to add a pop of color using a vegetable packed with vitamins and health benefits, then reach for radicchio. This is a quick-growing Mediterranean leafy vegetable resembling red lettuce or cabbage, the varieties of which are named after the Italian regions from which they originate. Slightly bitter tasting and wine-red leaves set this vegetable apart from other leafy vegetables.

History of Radicchio

The radicchio plant belongs to the daisy family and is a slightly bitter-spicy form of chicory, related to Belgian endive.3 In 79 A.D., Pliny the Elder mentions this vegetable from the Veneto region of Italy in his encyclopedic "Naturalist Historia." He noted the plant appeared to be good for insomnia and purifying the blood.

Radicchio was originally cultivated by planting wild seed in the fields and vegetable gardens.4 Pliny attributed the plant to an Egyptian genetic breeding product on chicory, and not part of the lettuce or cabbage family as you might assume from its appearance.5 In the Middle Ages, radicchio was popular among monks who welcomed a vegetable adding zest and flavor to an otherwise bland meal.6 It also was found on the tables of nobles in both cooked and raw form.

Although the historical plant was tasty, the modern-day Radicchio Rosa was developed in the 1860s by a Belgian who applied techniques used to whiten Belgian endive called imbianchiamento, or "whitening."7 Plants were harvested in late fall and their outer leaves trimmed and discarded. They were then packed into mesh baskets and kept in darkened sheds as their roots were bathed in circulating spring water. During this process the leaves take on a pronounced wine-red color.

Radicchio Has a Range of Variety and Flavor

Like most vegetables in Italy, radicchio is seasonal and appears in the markets in late November.8 The vegetable is tastiest after the first frost period, and in recent years it has been introduced to California's Napa Valley and is becoming more popular in the U.S. due to its good flavor and health benefits. A mature plant is between the size of an orange and grapefruit, with crisp leaves offering a bitter flavor with a hint of spice.

While the vegetable is used widely in Italy where at least 15 varieties are grown,9 there are five varieties more commonly found in the U.S. including:10,11,12

  • Chioggia (Rosa di Chioggia): This is the most common radicchio variety, resembling a compact head of cabbage with compact beet-red, bitter leaves and white ribs.
  • Rossa di Verona: Also called Verona Red, this is another favorite radicchio producing a bright red head with prominent midribs and veins. The plant was bred from Rossa di Treviso in the 1950s and is longer and more oblong than its predecessor.
  • Rossa di Treviso: This was the first red chicory developed in the 16th century, growing green and bitter in hot weather. The leaves are long, conical and compactly arranged. A second growth produces bright-red, cone-shaped head with a pure-white central ribbing.
  • Early Treviso: The plant has a tapered heart with a compact head, crimson and pink leaves, and resembles a small reddish-purple romaine lettuce.
  • Castelfranco: This is a hybrid of radicchio and endive with crinkled lettuce-like leaves, with wine-red speckles, a mild flavor and tender texture.

Growing Garden Radicchio

Growing radicchio in your backyard ensures you're eating plants without chemical toxins. While the plant grows best in cool weather, it's also heat-tolerant. In hotter climates the plant does not form into tight heads like cabbage, but remains more open and loose-leafed. Cool weather sweetens the flavor of the plant, while warmer weather keeps the flavor bitter. Most varieties require between 60 and 70 days to mature and the plant benefits from a long cool season.

When planting through a mild winter, your garden may benefit from plastic sheeting around the radicchio plants to maintain growth.13 In regions where the winters are cold, plants are grown best in spring and early summer, but thrive in fall and winter in warmer weather regions.14

The soil should be prepared to encourage good drainage and organic compost added weeks before planting. Radicchio can be grown in raised beds or in containers where the soil is prepared in much the same manner. During cooler weather the plant grows best in full sun, but in summer months, plants benefit from afternoon shade.15

In the spring, start seeds indoors eight weeks before the last frost. Transplanting seedlings may work better than direct seeding to the soil.16 If you consider direct seeding, sow them in rows in raised beds and thin the plants 8 inches apart after leaves begin to form. When you transplant seedlings, leave 8 to 10 inches between plants and space rows 18 inches apart. If this is your first season for planting radicchio, consider transplanting seedlings every few weeks to determine the best time in your region.17

Like heads of lettuce, the plant puts down shallow roots and will benefit from consistent soil moisture. However, too much water can result in heart rot. Therefore, it is crucial to plant in a well-drained area or use raised beds for a successful crop.18

Once the plants are established, covering the area with organic mulch, such as a thick layer of untreated grass clippings, hay or straw, helps maintain moisture and prevent evaporation as well as reducing weed growth. Infrequent watering will increase the bitter flavor of the leaves. The most important watering time occurs seven to 10 days before the heads mature.19

Few Pests and Diseases Affect Radicchio

Radicchio plants are plagued by some of the same types of pests as the cabbage family, such as aphids, beetles, thrips and ants. The plant is also susceptible to a variety of fungal issues and powdery molds. These usually occur when there is inadequate drainage and are more common in areas with extremely wet conditions.20 Ensuring your plants are rooted in well-draining soil will go far to reduce the potential for fungal disease.

Aphids more commonly appear in the spring months and respond well to a mild household detergent.21 The soap damages the insect's protective coat and causes them to dehydrate and die. The same can be used for thrips, tiny black-winged insects that pose a serious pest problem when present in large numbers.

Ants can destroy a crop of radicchio and many of the other plants in your garden. However, there are several ways to treat an invasion.22 Baking soda is poisonous to ants and sprinkling it around your plants will ensure they stay away. Coffee grounds, chili powder, cinnamon and peppermint will also deter ants. You may also remove ants from your plants by mixing a spray bottle with one part white vinegar and one part water. The acid in the white vinegar will kill the ants on the plant.

Grasshoppers also enjoy feasting on the tender leaves of early seedlings. To deter grasshoppers you can apply a homemade garlic spray by blending two bulbs of garlic with 10 cups of water.23

Heat until boiling and then let it set overnight. Fill a spray bottle with one part of the solution and three parts water, spraying on the affected plants and including the underside of the leaves as well. Another option is to attract natural predators into the garden, such as many species of birds that enjoy feasting on grasshoppers. To attract these birds, set up a bird bath or a feeder in the yard.

Harvesting and Storing Your Crop

In this short video, horticulture specialist Kim Tuscano shows plantings of radicchio and discusses proper methods of harvesting and over-wintering. The leaves of the radicchio plant may be harvested at any time, but the compact head will not form until the latter part of the growing season. When the heads are firm to the touch, normally near 65 to 70 days, they're ready for harvesting.

As Toscano demonstrates in the video, cut the head close to the ground, just above the soil line. As the heads mature they may develop a more bitter taste. Not all heads in your radicchio crop will form and mature at the same time.

Interestingly, crops grown in the fall will form better heads than those grown in the spring. In some cases, if your region has a mild winter, you may get a second crop from the same plant in the spring. Radicchio keeps well in the refrigerator for approximately a week or two when the temperature is below 46.4 degrees Fahrenheit.

Highly Rated Garden Vegetable for Health Benefits

Health benefits from radicchio are related to more than the plant's high levels of vitamins. Radicchio is known as the vitamin K vegetable, as it has the highest amount in one serving. Your body has a limited ability to store vitamin K, so it is recycled in an oxidation-reduction cycle in order to be reused multiple times.

Vitamin K is a cofactor and present in many vitamin K dependent proteins involved in blood coagulation, bone metabolism and the prevention of vessel mineralization. Abnormal mineralization of blood vessels is a major risk factor in cardiovascular disease. Inadequate levels may precipitate the formation of calcium in blood vessels.24 Radicchio is also packed with:25

Vitamin A

B1 (thiamin)

B3 (niacin)

B5 (pantothenic acid)

B6 (pyridoxine)

B9 (folic acid)

Vitamin E

Vitamin C

Calcium

Copper

Magnesium

Phosphorus

Iron

Potassium

Selenium

One cup of shredded radicchio, equaling 40 grams, also has 43 grams of plant-based omega-6 and omega-3 fats, and a single serving contains 13 percent of the recommended daily allowance of vitamin C26 (ascorbic acid).

Vitamin C is a powerful antioxidant and an essential water-soluble vitamin, as you do not have the ability to make it and it must be obtained from your diet.27 It plays a significant role in the formation of collagen, important to antiaging skin care.28 Vitamin C also functions as an essential cofactor in the number of enzymatic reactions, and has been found to:

  • Reduce the risk of cardiovascular disease
  • Support the immune system
  • Support the growth of beneficial gut bacteria
  • Support neutralization of environmental toxins

Also found in radicchio are:29,30

  • Lactucopicrin (intybrin): Responsible for radicchio's bitter flavor, lactucopicrin may be an effective antimalarial agent, and possesses sedative and analgesic effects.
  • Phenolic flavonoid antioxidants zeaxanthin and lutein: These carotenoids protect your eyes from age-related macular degeneration by filtering out harmful ultraviolet rays.
  • Inulin: This substance could help balance your body's blood sugar levels and reduce risk for cardiovascular diseases like strokes and/or heart attacks. Furthermore, the combination of inulin and some polysaccharides could stimulate the growth of beneficial gut bacteria like Lactobacilli and Bifidobacteria, and potentially prevent harmful bacteria growth.

Using Radicchio in Recipes at Home

Radicchio can be eaten raw or cooked, using either the individual leaves or cutting the head. Adding Himalayan sea salt when serving the leaves, which are slightly more bitter tasting than the head, will help to counter the bitterness. Consider a simple side dish of radicchio leaves tossed with olive oil and salt. The plant may be blended with milder lettuces and greens for a fresh salad or roasted and grilled in chunks.31

Radicchio can also be sautéed, baked or added to soups, rice dishes and even omelets. The bitter flavor of the leaves works well with balsamic vinegar, butter, Italian cheeses, salami and lemon. Plants purchased at the grocery store are often imported from the Mediterranean.

Prepare your plants by trimming off the outer leaves as you would a cabbage and washing the head under cool running water. Now the head can be cut into quarters or wedges and mixed with your favorite dishes.32 Although grilling radicchio chunks is popular, it is ideal to eat this veggie raw as you'll obtain most of the nutrients this way.33 If you want an easy recipe to try, consider this radicchio salad with endives, orange and walnuts recipe:34

Radicchio Salad With Endives, Orange and Walnuts

Ingredients

  • 3 cups thinly sliced radicchio
  • 3 cups chopped endive
  • 1 cup peeled and segmented orange
  • 1/3 cup walnuts
  • 2 tablespoons olive or walnut oil
  • 2 tablespoons orange or grapefruit juice
  • 1 tablespoon lemon juice
  • 2 teaspoons maple syrup
  • 1/4 teaspoon sea salt (or to taste)
  • Black pepper to taste

Instructions

  1. Combine the radicchio, endive, orange, and walnuts in a large mixing bowl.
  2. Whisk the oil, juices, syrup, sea salt and black pepper. Toss dressing with salad and mix well.
  3. Serve immediately.