CUCUMBER FARMING IN KENYA: PRODUCTION GUIDELINE

Cucumber, Cucumis sativus, is part of the Cucurbitaceae family and is said to have originated from Nepal.  They are sensitive to frost and are grown in the open fields or the greenhouses dependent on the type. Greenhouse cucumbers are parthenocarpic, meaning that they produce fruit with no need for fertilization and the fruits are usually seedless. 

Cucumber Farming in Kenya

The cucumber fruit has a mild flavor with a thin, tender, dark green outer skin that needs no peeling. It has roughly cylindrical, elongated, with tapered ends and range from 12-38cm shape when ready for harvest. Cucumbers are usually eaten in salads, or as accompaniments to different foods.

Varieties in Cucumber Farming in Kenya

Jude F1, Envoy F1 and GS 18-4115 are the best cucumber varieties for farming in Kenya:

1. Jude F1: This early-maturing variety takes about 75 days to reach maturity after transplanting. With a spacing of 60 cm by 45 cm, an acre can yield 4-5 tonnes of fruit, with each fruit weighing 50-75 grams. Jude F1 cucumbers are long, cylindrical, medium green, and measure approximately 10 cm by 1 cm.

2. Envoy F1: Known for its high resistance to cucumber mosaic virus, cucumber vein yellowing, and powdery mildew, this variety produces dark glossy green fruits that measure 22-30 cm in length and have a diameter of 5 cm. It is highly recommended for greenhouse farming.

3. GS 18-415: This slicer cucumber is suitable for both greenhouse and outdoor farming. It matures early, producing dark green fruits measuring 19-22 cm in length and weighing approximately 240 grams.

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Climatic Requirements in Cucumber Farming

• Optimum germination temperature: 25-28°C, night temperature not lower than 20°C.

• Optimum growth temperature: 25-30°C, night temperature not lower than 18°C.

 Soil Requirements in Cucumber Farming

Greenhouse or tunnel cucumbers are usually planted in bags filled with sawdust or a combination of coconut fiber, peat, perlite, polystyrene, or bark. A good potting mixture has good water holding capacity, adequate drainage and should not decompose rapidly. Peat, vermiculite and coconut fiber are the most popular amendments added for increased water holding. Perlite and horticulture grade sand are commonly used to improve drainage. Some growers prefer to plant in soil.

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Cucumber plants are deep-rooted crops, which grow best in well-drained, fertile, soil that is low in soluble salts and free of soil-borne diseases. The soil should be at least 1.2m deep and sandy loam soil is preferable to light sand or clay. Well-composted organic matter may be worked into the soil before planting to increase nutrient levels and water-holding capacity. Seeds can be directly sown, but are usually germinated in seedling trays and then transplanted. 

Cucumber roots are very sensitive and care must be taken during transplant not to damage them. The use of a sterile seedling medium is recommended to prevent disease infection.

Greenhouse Cucumber Farming Types

The most popular types grown in greenhouses are the long, seedless hybrid F1 varieties often referred to as English cucumbers. These seedless varieties are gynoecious in flowering habit (produce only female flowers), and produce parthenocarpic fruit (not needing pollination for fruit development). The fruit have thin, edible, smooth green skin, which can have slight longitudinal ridges/ribs. Varieties with shorter fruit, known as midi cucumbers are also gown for some markets.

A Flowering Cucumber Crop

Traditional Seeded or Field Cucumber Farming Types

The traditional seeded varieties produce both male and female flowers and require pollination to form healthy fruit, which have seeds and white spines. These are more suited to open field production, and are commonly called Field Cucumbers. In order for pollination to take place pollen must be transferred from the male flowers to female flowers. Outdoors, bees normally do the pollination under good weather conditions, but in greenhouses it is the grower’s responsibility to transfer pollen.

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When cucumbers are not properly pollinated, the fruit will be misshapen and poorly developed, especially on the blossom end of the fruit. The fruit should be harvested when they have reached full diameter but while the seeds are still small and soft. If the fruit are light green or yellow or have hard mature seeds, the fruit are considered over-mature.

Cultivation Practices in Cucumber Farming

Germination and Transplanting

The optimum germination temperature for cucumber seed is 25 degrees Celsius to 28 degrees Celsius. Daytime temperatures should be maintained between 23°C to 25°C and night temperature not lower than 18 degrees Celsius. Seedling must be kept moist but not water soaked. Seedlings in seeding trays could be transplanted to bags three to four weeks after germination, or the seed can be planted directly into the planting bags. 

Begin fertilizing three days after transplanting or when true leaves have begun to emerge. Plants should be watered frequently with the fertilizer solution. A minimum of 14 hours of strong direct light is required for developing seedlings.

Lentils price has remained at an all time meaning the market is there but the supply is low. Have you thought about growing them for sale? See Lentil ( Lens Culinaris) Farming in Kenya

 Plant Spacing

The light availability, production system and trellising method will affect the exact spacing required. Generally, under good light conditions, 2.2 to 2.5 plants per square meter should be sufficient. This should ensure good air circulation and adequate light for fruit production. A well-ventilated tunnel will have lower disease pressure and will have easier access for spraying of pest and diseases.

Fertilization and Irrigation

In order to prevent over or under fertilizing, it is very important to have a soil and water analysis to be used for cucumber growing. This should be taken into account when calculating the fertigation program. The ECW (electrical conductivity of the water) must be taken into account when determining what the total EC should be. 

EC and pH should be checked when the fertigation mix flows out of the tank, again where it flows into the growing media or soil, and once more when it flows out of the growing media or soil. 

Generally, to lower the pH either nitric, sulfuric or phosphoric acid may be recommended. Potassium hydroxide is usually used when it is needed to raise the pH. If the source water is alkaline as a result of high bicarbonate concentrations, the pH should be amended before the fertilizer salts are added to prevent precipitation.

Cucumber Fruit

Pests and Diseases in Cucumber Farming

There are many difficulties associated with cucumber cultivation such as insect pests and diseases, varieties and markets.

Pests and diseases on cucumber are not as many as in solanaceous or the cabbage family crops. Usually, problems with pests and diseases are linked to crop timing and yield.

Major diseases of cucumber, such as angular leaf spot, powdery mildew, downy mildew and soil-borne diseases such as bacterial wilt can be prevented by cultivation and other cultural practices. Growing resistant varieties can effectively reduce insect pests and diseases.

Trellising and Pruning in Cucumber Farming

In order to get an optimum cucumber production, a proper balance is needed between the vegetative growth and fruit load. This balance is achieved by constant pruning of shoots, foliage, fruit and flowers. 

If the canopy of leaves is too dense it will shade fruits from sunlight, causing them to be pale or unevenly colored. If fruit are not pruned and too many are allowed to form at any one time, a large proportion may be aborted, malformed or poorly colored because the plant may not have sufficient reserves.

Therefore, generally only one fruit should be allowed to develop in a leaf axil, although vigorous cultivars can sometimes mature more than one fruit at a node. Short, midi cucumber types will support several fruit per node. 

Cucumbers are trellised on a string or wire system. Various trellising methods are used by different growers. The main aim should be to capture sunlight uniformly throughout the greenhouse.

Cucumber Harvesting

Cucumbers are harvested as immature fruit when full length has been reached. At suitable harvest maturity, a jellylike material has started to form in the seed cavity. However, if the fruits are left on the plant for too long there is a likelihood of a reduced harvest. Cucumbers are hand harvested, normally 3 times per week, depending on the weather and growth stage of the plant.

Harvest at the coolest time of day and avoid any heating of the harvested product. To reduce damage and disease use a sharp clean tool to cut the fruit from the plant. The harvested fruit should be placed in clean harvesting containers and placed in a shaded area. It should be transported for packing as soon after harvest as possible. Cucumbers should be handled carefully and care taken not to damage the thin skin.

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Post-Harvest Handling

Cucumbers lose moisture quickly and have the tendency to soften during storage. Marketable cucumbers should be sorted according to size and quality and individually wrapped in clear plastic. The optimum storage temperature for cucumbers is 10-12.5 degrees Celsius at relative humidity of 95%. Storage or transit temperatures below this range should be avoided as this will result in chilling injury after 2-3 days.

Frequently Asked Questions

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