Aside from grouping, a system of classifying and naming is essential to the proper description and identification of a given vegetable crop. Botanically, a vegetable plant is identified by its Latin binomial, giving genus and species, together with botanical variety if needed. It is further identified according to horticultural variety, or cultivar, and often strain. A cultivar includes plants similar in important physical characteristics that are maintained true to type from one population to the next. Strains within varieties differ less significantly and have most of the characteristics of the variety. The designation of a variety of cabbage would be as follows: cabbage (Brassica oleracea var. capitata), horticultural variety Golden Acre, resistant strain.
Botanical and Morphological
Vegetables may be grouped into botanical families on the basis of plant characteristics. They may also be classified morphologically according to the particular part of the plant that is harvested as food. See accompanying tables.
Temperature Requirements
The nonperennial vegetables commonly grown in temperate zones may be separated into cool-season and warm-season vegetables. For most vegetables this grouping parallels the separation into vegetative parts and fruit parts.
In general, cool-season vegetables prefer monthly mean temperatures of 60° to 65° F (15.5°–18° C). They are intolerant of high temperatures but tolerant of some frost. Cool-season crops include cabbage, cauliflower, turnips, radishes, spinach, lettuce, potatoes, celery, and peas. They have a restricted habit of growth and a short growing season. The part eaten is vegetative. It reaches a usable size in a relatively short period. Hence, these crops are grown in most agricultural areas of the world. The vegetable should be stored near 32° F (0° C) after harvest.
In contrast, warm-season crops generally prefer monthly mean temperatures above 65° F (18° C). They are intolerant of low temperatures and of frost. Warm-season crops include tomato, eggplant, okra, pepper, melons, and cucumber. They have a relatively unrestricted habit of growth and require a long growing season. Production is limited to summer in the temperate areas, where it is often desirable to extend the growing season by the use of forcing structures or protective devices. The edible part is the fruit structure. The vegetable should be stored above 50° F (10° C) after harvest.
Cultural Practices
Vegetables may also be classified according to their cultural requirements. In such a system, vegetables may be grouped in the following categories: perennial crops, greens, salad crops, cole crops, root crops, bulb crops, the potato, the sweet potato, beans and peas, solanaceous fruits, cucurbits (vine crops), sweet corn, and okra.
