The cucumber is one of the oldest of our cultivated vegetables. It has been cultivated in India for at least 3,000 years, but according to DeCandolle was not introduced into China until the second century before Christ. It was first grown in England in 1573. Cucumbers were grown by the earliest settlers in this country, and the crop has been increasing in commercial importance. It is used largely for slicing and pickling and to some extent for cooking. The main trucking districts of the South regard it as one of their standard crops. In some parts of the North it is grown on a large scale for pickling. It is third in importance of the vegetables produced under glass.
The cucumber is an annual, belonging to the genus Cucumis and to the family Cucurbitaceae. The stems are rough, creeping, angular and flexible, bearing tendrils and cordate obscurely five-lobed leaves.
Both staminate and pistillate flowers are produced in the axils of the leaves, the staminate appearing first generally near the bases of the stems. The flowers are large, yellow and usually on short peduncles. They require the assistance of insects to effect pollination. In greenhouses this is accomplished by means of bees or by hand pollination. There are two types of fruit—the English, long and slender, and the American, short and thick.
English varieties are not grown in this country except to a limited extent in greenhouses. The best representative of the American type is White Spine. It is especially desirable for slicing. For this purpose it is grown under glass as well as in the open. The various strains of White Spine are grown more largely than all other varieties combined. Several varieties are regarded as especially valuable for pickling. Among them may be mentioned Chicago Pickling, Boston Pickling and Fordhook Pickling.
The cucumber is grown commercially, on a large scale, under a wide range of climatic conditions. All the trucking sections of the South and of the Atlantic Coast are favorable to the production of the early crop, while the cooler summers of the North are well adapted to growing picklers. The plants are sensitive to frost as well as to extreme heat, but thrive under cooler conditions than the melons. Because of the short period required to mature the crop, there are very few sections in the United States where it cannot be grown successfully.
The light sandy soils are best for the early crop, if earliness is the chief consideration; but yields are larger and the bearing period longer in the heavier soils. The cooler clay loams are often used for the late crop and for the growing of picklers. Whatever the type of soil, it should be moist but not wet.
Practically all of the seed is grown in this country. Careful selection is important. Since market requirements differ somewhat, this factor should be considered when buying or when saving seed from the home planting.
Earliness is such an important factor in securing remunerative prices that many growers start some of their plants under glass. Greenhouses are most suitable for the purpose, although hotbeds, glass and cloth-covered frames are often employed. Formerly, inverted squares of sods were used extensively in which to start young plants. They are still popular with some growers. Rather thick, tough sods are cut in squares of about 6 inches, inverted and hollowed out to provide a receptacle for soil and seed. They furnish excellent conditions, but are troublesome to prepare and are not so convenient to handle as earthen or paper pots, berry baskets and dirt bands. The pots or other devices should not be less than 4 inches in diameter and should be filled with a light, rich, porous, garden soil. It is an advantage to place an inch of rotten manure in the bottorn of berry baskets or dirt bands before rilling with soil. Six to eight seeds should be planted in each, and the plants then thinned to the strongest two or four. It is customary to leave only two plants, while a greater field area may be covered by starting four together and then spacing more liberally in the field than if there were only two in each hill.
The seeds should not be sown more than a month before the time for hill planting, for if too far advanced there will be danger of a check in growth when the plants are transferred to the field. A night temperature of 60 degrees and a day temperature of 70 are suitable for germination and the growth of the plants. The plants should be hardened by moderate watering and by free ventilation before setting in the field.
Early plowing and frequent harrowing before planting are important. It is often possible to grow a green manurial crop in the fall to plow down in the spring. For the early crop some growers prefer to throw up the land into slight ridges, thus securing better drainage and somewhat warmer soil conditions.