The courgette is a vegetable which belongs to the family Cucurbitaceae and is known scientifically as Cucúrbita pepo.
It is an annual herbaceous plant with compact foliage and an indefinite growth rate.
The root system consists in a main root which reaches an extensive growth rate when compared to the secondary roots which only spread out superficially.
It possesses a main stalk from which secondary stalks grow but they will wither unless pruning is carried out in order to induce them to branch out into two or more stems.
The plant can reach up to more than a metre in length; it is thick and cylindrical in shape, with a prickly surface which is rough to the touch. It possesses a series of short internodes, from which the leaves, flowers, fruits and various thorns sprout.
The leaves are palm−shaped, green in colour, they are held up by long strong petiole, which sprout directly from the stalk, alternately and in a spiral fashion.
The blade is large with a glabrous shaft and a rough underside which is covered in prickly hairs.
The flowers are large solitary axillary blooms which are bell−shaped and yellow in colour. They can be either masculine or feminine, both sexes coexisting separately on the same monoicous plant.
The calyx consists of five pointed green sepals. The corolla is made up of five yellow petals.
The fruit is fleshy pepo which is unilocular without a central cavity, variable in colour, and it might be smooth, stripy or mottled.
The seeds are a yellowish-white colour, elongated and oval in shape with a pointed tip. They are smooth with a groove along the length of the seed, which is parallel to the outside edge.
The courgette is not particularly demanding as regards temperature requirements; in fact it is less demanding than the melon, the cucumber and the water melon.
The optimum temperature for vegetative growth is between 25ºC and 30ºC and during the flowering stage this will vary between 20⁰C throughout the night and 25ºC during the day.
The optimum relative humidity of the air in the greenhouse will vary between 65% and 80%.
The bushy foliage of the plant and the high water content of the fruit, make it obvious that the crop in question will require plenty of water; this means it will need to be watered on a regular basis.
As far as the courgette is concerned, the length of daylight will not have excessive repercussions on plant growth as there do not tend to be any problems with regard to flowering. Due to this fact, courgettes can be grown in greenhouses at any time of the year. However, sunlight will aid photosynthesis and will also play a part in maturing the fruits and in their earliness.
The courgette easily adapts to all types of soil, although loamy, deep, well drained soils are the most recommended.
Nevertheless, the courgette is very demanding where the intake of organic materials is concerned.
The optimum pH level of the soil varies between pH5.6 and pH6.8 although the courgette can adapt to soils with levels between pH5 and pH7.
This is a species which is fairly tolerant towards to both soil salinity and the water used for irrigation purposes; it is however, less tolerant than the melon and the water melon and more tolerant than the cucumber.