Kohlrabi

Basic Information

Common Name: Kohlrabi

Scientific Name: Brassica oleracea var. gongylodes

Native Habitat: Europe

History / Discovery / Cultivator

Kohlrabi, sometimes referred to as the German turnip, boasts a fascinating history intertwined with the evolution of the Brassica oleracea species. This species is a botanical powerhouse, giving rise to a diverse range of vegetables, including cabbage, broccoli, cauliflower, kale, and Brussels sprouts. Kohlrabi, however, stands out with its unique swollen stem, which is the edible part of the plant.

The precise origins of kohlrabi are somewhat murky, but botanical historians generally agree that it likely arose in northern Europe sometime in the late Middle Ages or early Renaissance. While the other members of the Brassica oleracea family have roots stretching back to antiquity, kohlrabi is a relatively newcomer, with the earliest documented descriptions appearing in the 15th century. It’s believed to have originated from a wild cabbage ancestor, potentially through selective breeding by farmers who favored plants with thickened stems. The name “kohlrabi” itself is a testament to its German heritage, combining the German words “kohl” (cabbage) and “rabi” (turnip), reflecting its perceived resemblance to both vegetables.

One of the earliest documented references to kohlrabi can be found in the writings of the German botanist Hieronymus Bock in 1553. Bock described the plant and noted its cultivation in Germany. From Germany, kohlrabi gradually spread to other parts of Europe, including England, France, and Italy. By the 16th and 17th centuries, it was becoming increasingly popular as a garden vegetable and a staple in some regional cuisines.

The introduction of kohlrabi to North America occurred in the early 19th century. It was initially viewed with some skepticism, perhaps due to its unusual appearance and unfamiliar flavor. However, as European immigrants brought their culinary traditions to the New World, kohlrabi slowly gained acceptance. Today, it’s grown in many parts of the United States and Canada, although it remains less widely cultivated than other Brassica oleracea vegetables.

Throughout its history, kohlrabi has been valued for its versatility and nutritional benefits. The swollen stem can be eaten raw or cooked, offering a mild, slightly sweet flavor reminiscent of turnip or cabbage. It’s a good source of vitamin C, fiber, and potassium. The leaves are also edible and can be cooked like spinach or kale.

Over the centuries, various cultivars of kohlrabi have been developed, differing in color (ranging from pale green to purple), size, and growth habit. Some cultivars are specifically bred for early maturity, while others are more suited for storage. Modern breeding programs continue to focus on improving traits such as yield, disease resistance, and flavor.

While no single individual can be definitively credited with the “discovery” of kohlrabi, its emergence as a distinct vegetable is a testament to the ingenuity and selective breeding practices of early European farmers. These cultivators recognized the potential of the Brassica oleracea family and, through generations of careful selection, transformed a wild cabbage ancestor into the unique and nutritious vegetable we know as kohlrabi. Its journey from a relatively obscure vegetable to a globally cultivated crop reflects the enduring power of human intervention in shaping the plant world.

Plant Care Summary

Botanical Insights

Adaptations

Kohlrabi’s most notable adaptation is its swollen, globe-shaped stem, which is an above-ground storage organ. This adaptation allows the plant to store water and nutrients, enabling it to withstand periods of drought or nutrient scarcity. The stem’s smooth, waxy surface also helps to reduce water loss through transpiration. The plant’s ability to thrive in relatively cool temperatures allows it to be grown in a wide range of climates. Kohlrabi is also relatively quick-growing, allowing for multiple harvests in a single growing season.

Propagation Methods

Kohlrabi is typically propagated from seed. Sow seeds directly into the garden or start them indoors 4-6 weeks before the last frost. Transplant seedlings when they have developed several true leaves. Ensure adequate spacing between plants to allow for proper bulb development. Successive sowings can be made every few weeks to ensure a continuous harvest.

Toxicology

Kohlrabi is considered non-toxic to both humans and pets. All parts of the plant, including the stem, leaves, and roots, are edible. However, consuming large quantities may cause mild digestive upset in some individuals due to its high fiber content.

Common Problems

Pests:

• Cabbage worms
• Aphids
• Flea beetles

Diseases:

• Clubroot
• Blackleg
• Downy mildew

Other:

• Cracking bulbs: Caused by inconsistent watering or rapid growth spurts.
• Woody texture: Occurs when kohlrabi is allowed to grow too large or is harvested too late.
• Poor bulb formation: May be due to insufficient sunlight, poor soil, or inadequate fertilization.

Rarity & Value

Rarity:

Kohlrabi is not generally considered a rare vegetable. It’s widely available in many parts of the world and is relatively easy to grow. However, certain heirloom varieties or cultivars with unique colors or flavors may be less common and more sought after by gardeners and chefs.

Value:

The value of kohlrabi is typically determined by its size, freshness, and quality. Smaller, younger bulbs tend to be more tender and flavorful than larger, older ones. Organically grown kohlrabi may also command a higher price. The market value can be influenced by seasonal availability and local demand. Specialty varieties may also fetch a higher price due to their unique characteristics.