Cucumber

The cucumber, scientifically known as Cucumis sativus, is a climbing vine that lives for a single growing season. It belongs to the Cucurbitaceae family and produces fruits that range from cylindrical to round, typically used as a vegetable in cooking. The three primary categories are those meant for fresh slicing, those intended for pickling, and seedless varieties.

Its origins trace back to Asia, specifically an area covering India, Nepal, Bangladesh, parts of southern China (Yunnan, Guizhou, Guangxi), and northern Thailand. Today, it is grown across most continents, with numerous commercial types traded worldwide. In North America, plants called "wild cucumbers" belong to the genera Echinocystis and Marah, but they are not closely related to the true cucumber.

Cucumbers have been under cultivation for at least 3,000 years. Roman Emperor Tiberius had them available year-round, and Charlemagne ordered them grown during the Middle Ages. The Spanish introduced cucumbers to the Americas in 1494 as part of the Columbian exchange. China dominates global production, accounting for over three-quarters of the total.

Description

As a vine, the cucumber plant roots in soil or a soilless medium and uses thin, spiraling tendrils to climb trellises or other supports. Without support, it sprawls along the ground. Its large leaves form a canopy over the fruits.

Typical cucumber fruits are roughly cylindrical, often elongated with tapered ends, and can reach up to 62 cm long and 10 cm in diameter. Botanically, the fruit is a pepo—a type of berry with seeds and a tough rind—though it is treated as a vegetable in cooking. Cucumbers are 95% water.

Cultivars and pollination

Most seeded cucumber varieties require pollination, often relying on honeybees, bumblebees, or other wild bees. Thousands of beehives are brought to fields just before bloom. These plants are usually self-incompatible, needing pollen from another plant to produce seeds and fruit, though some self-compatible types, like the 'Lemon cucumber', exist. Parthenocarpic cultivars produce seedless fruit without pollination and are often grown in greenhouses, though bee visits still boost fruit set.

Traditional varieties produce male flowers first, then female, in roughly equal numbers. Newer gynoecious hybrids produce almost all female blossoms and are often interplanted with a pollenizer variety, with increased beehive density. Temperature changes can induce male flowers even on these hybrids, sometimes providing enough pollen.

Herbivore defense

Cucumbers produce cucurbitacin C, a bitter compound that may deter herbivores like insects, nematodes, and wildlife. This chemical defense is found in the leaves, cotyledons, pedicel, carpopodium, and fruit, and is under preliminary research for its role in resisting environmental stress.

Taxonomy and genetics

Carl Linnaeus described Cucumis sativus in 1753 in Species Plantarum. The genus Cucumis, also created by Linnaeus, now includes 61 accepted species according to Plants of the World Online. C. sativus is the only member with 2N=14 chromosomes. Its genome was sequenced in 2009, and studies of genetic recombination during meiosis have mapped DNA double-strand breaks and crossovers in high resolution.

In 2024, global production of cucumbers and gherkins reached 88 million tonnes, with China contributing 78%. Raw cucumber with peel is 95% water, 4% carbohydrates, 1% protein, and negligible fat, providing 65 kJ of energy per 100 g. It is low in most micronutrients but offers 14% of the Daily Value for vitamin K. The distinctive aroma comes from compounds like trans,cis-2,6-nonadienal (cucumber aldehyde) and isomers of 2-nonenal, which also give a mild melon flavor. The bitter taste in the rind is due to cucurbitacins, and unpeeled cucumbers have higher polyphenol content.

Cucumbers are classified into slicing, pickling, and seedless/burpless groups. Slicing varieties are grown for fresh eating, with large leaves that shade the fruit. Commercial slicers in North America are longer, smoother, and have tougher skin, while European types are smaller, thinner-skinned, and often sold wrapped in plastic. In Australasia, these are called 'telegraph cucumbers'.

Pickling cucumbers are shorter, thicker, and thinner-skinned. Gherkins, cornichons, or baby pickles are small cucumbers (1 to 5 inches long), often bumpy, used for pickling. The word "gherkin" comes from early modern Dutch gurken or augurken ("small pickled cucumber") and also refers to Cucumis anguria, the West Indian gherkin, a close relative. Burpless cucumbers are sweeter.