How to grow cucumbers

Learning to grow your own cucumbers. Tips and helpful information.

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 30ºC. 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.

The optimum pH range is pH 5,5 and pH 7.

The planting of cucumber plants in greenhouses is carried out with seedlings taken from seedbeds once they have produced between 2 and 3 well established leaves.

In order for transplanting to take place, holes are made in the soil and once the root ball is placed into the hole, it is covered and watered so the plant takes a firm foothold with regard to the root taking process.

The settings for planting are established depending upon the crop cycle. For early crops with a short cycle, the settings for planting are usually 1,5m×0,4m or 1,2m×0,5m.

If the crop being gown is a later crop or the idea is to extend production on into the colder months, then the settings for planting will be increased. The most commonly used settings being 2m between the lines and 0,5m between the plants, or 1,5m between the lines and 0,6m between the plants.

Pruning takes place a few days after transplanting has been carried out. With regard to cucumbers of the "Dutch type", the side shoots are removed in order to leave the plant with a single main stem. As concerning other types of cucumber, pruning methods are similar although the side shoots are not eliminated but blunted from the second leaf upwards.

The old, yellow or diseased leaves are removed from time to time in order to facilitate aeration.

Staking and tying the plants will maintain them in an upright position; it will also improve general aeration of the plants and will make it easier to take advantage of sunlight and to undertake all of the care necessary with relation to crop production. Once the plant reaches the wire it will then move towards the next wire situated at a distance of 0.5m away, while at the same time leaving a trailing shoot over the wire.

With the objective of increasing the effectiveness of cross pollenization, beehives of Bombus terrestris should be placed inside the greenhouse.

Cucumber plants will require fairly large quantities of water, especially at the fruit formation stage and throughout the growth stage.

With regard to nutrition, it is important to take into account the ratios of Nitrogen/Potassium throughout the whole of the crop cycle. Besides this, phosphorous is important; above all during both the root taking and flowering stages, as is calcium with regard to enhancing plant quality and protecting the plants against disease.

This is a crop that will require quite a large quantity of micronutrients, especially manganese and iron.

Whitefly and thrips are among the main plagues that are found to adversely affect the cucumber plant. In order to biologically control these plagues the release of auxiliary fauna is undertaken, the most commonly practised method being the use of Amblyseius swirskii.

Another plague of lesser importance, are aphids. Their biological control is carried out by the use of parasitoids such as Aphidius colemani.

The main diseases found to affect this crop are Mildew, Fusarium and Botrytis.

Depending upon both crop and temperature, the growth period from flowering to harvest will take between 55 to 60 days.

The fruits are usually harvested whilst still slightly unripe, prior to full seed development and before they harden.

Due to the fact that the cucumber itself contains a large amount of water, dehydration must be prevented by cutting the fruit during the coolest hours of the day.