The cucumber is a vegetable that belongs to the cucurbitaceous family, and which is known scientifically as Cucumis sativus.
It is an annual monoecious trailing, climbing, herbaceous plant whenever an adequate system of training ties or trellising is used.
The root system consists in a main root, which branches out into very fine superficial secondary roots which are white in colour. The main stem is angular and thorny with nodes at the point where the thorns and leaves develop. Secondary shoots will bud from each leaf axil.
The leaves are positioned alternately along the stem; they have stalks which are lobe or bell shaped with 3 or 4 dark green lobes, covered in a very fine down.
The flowers are yellow drooping leaf axils which are generally unisexual.
The male flowers appear grouped in the leaf axils of the secondary stems and are grouped together in clusters of 3 to 5 flowers.
The female flowers are also found in the leaf axils of the secondary stems. These appear after the male flowers and they are situated individually and not in clusters.
They have an inferior ovary with three thick bipartite stigmas.
The fruit is a fleshy, smooth or rough berry, depending upon the variety. The epicarp ranges from a green colour, in its immature state, to a yellowish orange once the fruit is ripe.
The pulp is watery and whitish in colour, with seeds on the inside situated throughout the length of the fruit.
The aforementioned seeds will be found in variable quantities and they are oval and slightly flat in shape and tend to be a whitish yellow colour.
Cucumber plants require more heat than melons, but less than courgettes.
The optimum daytime temperatures vary between 20ºC and 30º C. Depending on how the temperature increases within this range, early growth rate will increase.
The cucumber is a plant that requires high levels of humidity due to the large surface area of its leaves. The optimum relative humidity during the day is 60-70% and at night between 70-90%.
The cucumber plant will grow, flower and produce fruit in a normal way even when daylight hours become shorter. However, it will also tolerate a high intensity of light and the greater the amount of sunlight, the more abundance of crop yield will result.
Cucumbers may be grown in all types of loose soil as long as it is well drained and contains sufficient organic matter.
It is a plant that will tolerate certain amounts of salinity although less than the melon plant.