Cabbage & Kale Facts

Cabbage and kale are among the hardiest and most nutritious vegetables a home gardener can grow with ease. Both are handsome in the garden, with colors ranging from pale green through dark battleship blue, to deep reddish purple. Flavors range from mild to strong, and both lend themselves to dishes both raw and cooked.

Cabbages, with their leaves formed into heads, are more sophisticated than kales. Greek and Roman colonists brought cabbages to the Black Sea region; Slavs were growing cabbages in the 9th century. Soon cabbages worked their way north into Russia. Within several centuries, Russian princes paid tribute with garden plots planted with kapusta (as they called cabbage) in addition to gifts of racing horses and jewels.

The Celts of central and western Europe were influential in making cabbage a popular food plant. The first written record of “white” cabbage (hard-heading) was by Albert of Cologne in the 13th century. In 14th century England, the distinction was made between heading and non-heading kale or coleworts, as they were then called, but it wasn’t until a century later that descriptions of hard-heading cabbages were made in Europe. The English grew loose heading, crumpled-leaf Chou de Savoys (named for the Italian province) in the 1500s. The first record of “red” cabbage in England was in 1570.

On his third voyage in 1542, Jacques Cartier planted cabbage in Canada. Because of its popularity in Europe, it is believed that early colonists grew cabbage in the United States; however, the first written record was not until 1669. By the 1700s, both the colonists and Native Americans were growing cabbage.
Chinese cabbage has been cultivated and grown in Asia from earliest times, although it is not mentioned in Chinese literature until the 5th century. It was introduced from China to Japan in the 1860s; in the 1880s and 1890s immigrant laborers brought it to America.

Kales, with their loose leaves, are the most primitive members of the cabbage family. Their origins are in the eastern Mediterranean area and Asia Minor. Kales have been food crops since about 2000 B.C. In 350 B.C., Theophrastus described a savoyed form of kale. In Europe, kale was the most common green vegetable until the end of the Middle Ages. The first mention of kale (colewort) in America was in 1669; but because of its popularity in European gardens it was probably introduced earlier. Russian kale was brought to Canada (and then the U.S.) by Russian traders in the 19th century.

Celtic knowledge of cabbage was so ancient as to have influenced the Latin name, Brassica (from the Celtic word bresic,meaning "cabbage"). "Cabbage" is an Anglicized version of the French caboche, which means "head." The term has been used to refer to loose—and even non-heading forms of Brassica oleracea as well as to the modern hard-heading cabbage, classified as B. oleracea Capitata group. Kale is Brassica oleracea Acephala group (Acephala meaning non-heading). Chinese cabbage is more closely related to mustard than cabbage, as its botanic name reveals: Brassica campestris, Pekinensis group. They are all members of the cabbage family Brassicaceae (formerly the mustard family Cruciferae).

Classification Cabbage
The most common cabbages, Capitata or head-shaped group, are generally classified as one of three leaf and color types: green-leaved, which has smooth green leaves; red, with smooth reddish-purple leaves; and Savoy, with crinkled leaves. Within these three groups, the choices break down to head shape (round, conical or cone shaped, globe, or flat round), and harvest time (early, mid-season, or late). In all, the outer—usually darker—leaves are called wrapper leaves. Flat-headed cabbages are best for stuffing. Large, late cabbages are most flavorful and best for sauerkraut.

Classification Kale
Kale is a Scottish word derived from coles (Greek) or caulis (Roman), terms that refer to the whole cabbage-like group of plants. The German word kohl has the same origin. Sometimes called borecole, kale can grow in northern climates—often well into winter.

In summer, as the weather warms up, the flavor of spring planted kale becomes more intense—almost bitter. Kale actually tastes sweeter and tastier after being exposed to a light frost. Tender kale greens can provide an intense addition to salads, particularly when combined with other such strongly flavored ingredients such as dry roasted peanuts, tamari-roasted almonds, or red pepper flakes. Kales noted as “baby” and “mature” can be used raw when young and cooked when they mature.

Although kale varies in color from pale yellowish to deep green through deep steely blue to purplish red and almost black, it is usually classified by the leaf form and texture—Scotch types have very curled and wrinkled leaves, Siberian (or Russian) types are almost flat with finely divided edges, while heirloom ‘Lacinato’ is in a class of its own. Blue-green color is associated with greater cold tolerance. Japanese kale is primarily used for decorative or ornamental purposes.

How to Grow
Both cabbages and kales prefer cool weather and can withstand light frosts. They grow best in full sun in rich (mix plenty of organic matter, such as compost, humus, well rotted manure, or leaf mold into the soil before planting), moist, slightly alkaline (pH 7.0) well-drained soil. To avoid any soil borne diseases, rotate crops; i.e., do not plant any members of the cabbage family (including broccoli, cauliflower, kohlrabi, rapini, Brussels sprouts, mustard) in the same place for four years.

Start From Seed Indoors
Start cabbage seeds indoors eight to ten weeks before the last frost date. Sow the seeds 1/2 inch deep, in sterile starting mix. Water thoroughly. Once the seeds have sprouted, keep the soil lightly moist. Make sure the plants have plenty of light—a south facing window or fluorescent tubes—so they don’t become lanky. Feed the plants with half-strength liquid fertilizer every two weeks. Once the plants have two sets of true leaves, harden the plants off by setting them outside. Start with two hours a day, and increase by two hours each day until they remain outdoors overnight.

Set the plants at least 12 inches apart; space rows 24 to 36 inches apart, depending on the variety. To get the plants off to a good start and encourage root development, pour in one cup of a soluble starter fertilizer (diluted according to package directions) to each planting hole before filling it in. To avoid cutworm damage, place a tuna fish or cat food can (with top and bottom removed) halfway into the soil to act as a collar for the plant.

Start from Seed Outdoors
Chinese cabbage and kale are best direct seeded into the garden. In cool weather climates, you can start other cabbages outdoors as well, up to four weeks before the last frost date. For fall harvest, sow seeds in July. Conserve seed by grouping 3 to 4 seeds at the desired plant spacing instead of the traditional continuous row and then thinning and throwing away a lot of seedlings. Sow the seeds 1/4 inch deep. Water well; keep the top level of soil moist, especially for drier mid-summer planting. Once the seedlings are several inches tall, with at least two sets of leaves, pinch out all but the strongest one in each group.

Growing On
Keep plants lightly moist. This is especially important for plants started in the summer for fall and winter harvest. Side dress with nitrogen fertilizer when the plants are half grown, or foliar feed every three weeks. Mulch with 1 to 2 inches of organic matter, keeping the mulch an inch away from the stem of the plant. Mulching helps keep the soil moist, feeds the plants, and controls weeds. Irrigation is especially important to help the young plants withstand the intense sunlight and heat of summer and to supply the developing heads with sufficient water to develop quickly.

Insects and Pests
Among the most common pests are aphids and cabbage loopers. The small white moths in the gardens lay eggs that turn into cabbage loopers. Cover the plants with screening or floating row cover to prevent this. Control aphids by spraying with frequent hard blasts of water; try spraying with insecticidal soap or hot pepper spray.

Harvest and Storage
Cabbage: You can harvest cabbage anytime after the heads form. Cut the heads when they are solid (firm to pressure) but before they crack or split. Springy heads are not mature. For spring planted cabbages, cut the head only; do not pull up the whole plant. Cut as close to the lower surface of the head as possible; leave the loose outer leaves intact. Buds will grow in the axils of these leaves, forming “cabbage sprouts.” Pick them when they are firm and 2 to 4 inches across.

Store late fall or winter cabbage for several months in humid conditions as close to freezing as possible. Store only disease-free heads. Pull out the cabbages and hang in a moist cellar, roots and all, or cut heads, remove loose outer leaves and spread one layer deep on shelves or pallets in a moist root cellar.

Kale: Pick outer leaves as you need them and kale will keep producing new inner leaves. Harvest when leaves are large enough for intended use. Tender young leaves are best for salad, older leaves for cooking. Frost improves the flavor of kale. Mature plants survive to 10°F or below. Mark the site so you can find the fresh greens under the snow.

Use of Cabbage and Kale as Ornamental Edibles in Gardens
Kale and cabbage are gorgeous additions to a perennial or mixed border. In Anchorage, Alaska, you are likely to see Savoy cabbage growing in planting beds along the city streets next to petunias and geraniums. Deep purple ‘Red Winterbor’ kale pairs well with fall or spring pansies, curly parsley, and nasturtiums. Dark green leaved ‘Blue Ridge’ kale creates an exciting backdrop for flowerbeds.

Nutritional Values – Raw and Cooked
Dark green leafy cabbage is high in Vitamin C, iron, and folate. Cabbage also contains beta-carotene, potassium, and phyto-chemicals, such as glucosinolates—proven to reduce cancer, especially lung cancer. The pale center leaves are much less nutritious. Avoid overcooking as this depletes the nutritional content. Raw red, green, or Savoy cabbage has about 20 calories a cup; cooked it is 30 calories, while Chinese cabbage is only 11 calories a cup raw; 15 cooked, and is higher in Vitamin C than the other cabbages.

Whether raw or cooked, kale is a low calorie, high nutrition leafy green. A cup of raw kale has 60 calories; cooked it is 48 calories. Even cooked, where it can lose one-third or more of its nutritive value, a cup of kale provides the minimum daily requirement of Vitamins A and C and 13 percent of the calcium requirement. A good source of glucosinolates, Vitamin E, and manganese, kale is used as a green vegetable, steamed and served with butter or vinegar, or in soups. Unfortunately, kale is often used in salad bars as the decoration covering the ice rather than as a selection on its own.

The Cabbage & Kale Fact Sheet is provided by the National Garden Bureau.

© 2007 National Garden Bureau