Table of Contents
Cucumber belongs to the cucurbitaceae (gourd family). Most cultivars are monoecious, with separate male and female flowers in the same plant. Gynoecious or “all-female” cultivars produce only female flowers resulting in up to 13 times more female flowers than those obtained in monoecious cultivars. The cucumber is used as salad, pickle and also as cooked vegetable. It has a cooling effect, prevents constipation, useful in jaundice and its seeds have number of ayurvedic uses
Varieties grown in Bhutan
Shabi Genchu, Santon No 1 and Frontier (F1)
Cucumber is a warm season crops and grows best having temperature range between 20° to 25°c. Prolonged temperatures below 150 C and above 320C will slow down the growth of the plant and increase the bitterness of the fruit (cucurbitacin).
Though it is grown in a wide range of soil types, deep, fertile soils with good drainage and the pH ranging from 6.5-7.5 are ideal for its growth.
The field must be prepared well with 2-3 ploughings in order to bring the soil to fine tilth. In case if the field is covered with cover crops or green manure crops, it should be turned over 2-4 weeks prior to planting cucumbers to allow for litter decomposition.
Seeds are sown in Feb-March or June in the foothills. The soil is well pulverised and beds raised 15-20 centimeters high, 1 meter wide and 4-5 meters long. The seeds are then sown in rows 10 centimeters apart. Nurseries can also be raised in pluck trays where the media is prepared with the ratio 1:1:1
(FYM: soil: sand)
Cucumbers can be either direct seeded or grown from transplants but transplants can result in an earlier crop given that the seedlings are well hardened before shifting it in the main field. For direct seeding, sow 2-3 seeds per hole on ridges or raised beds at a depth of 1 inch and
spaced 60 centimeters between seeds.
Before sowing seeds, treat them with the suitable chemical to protect them from pest and disease and to increase viability. Seeds are treated with Trichoderma viride 4g/kg or Pseudomonas fluorescens 10g/kg or Carbendazim 2 g/kg of seeds.
Harden the seedlings for 5 days (Gradually reducing the frequency of water and exposing them to more sunlight). A good seedling is in the 4 or 5 leaf stage (about 4 weeks old), vigorous, disease-free, stocky and without flowers
The seedlings with 12-15 centimeters height with 4-5 leaves should be transplanted in the field. Transplanting is usually done in the evening or early morning to reduce transpiration rate. The seedlings are spaced 30cm apart and 120cm row to row. The seeding rate for transplant
production is 2.2kg/ha whereas 3-5kg/ha for direct seeding
Application of fertilizers
Fertilizer applications should be based on crop nutrient demands and stage of crop growth. It should be applied after having the soil tested. The general recommended rate in the region as per the NSSC (Soil fertility and Nutrition, 2013) is 10 t/ac of FYM and18:14:10 kg NPK/ac
as basal. Top dress 4-6weeks after planting (12kg N2/ac).
Cucumbers are susceptible to damage from wind and need the protection provided by windbreaks in wind-prone areas.
Cucumbers can be directly planted on a bare ground but the most effective planting method would be with the use of mulch (dry grass/plastic mulch)
3-4 weedings/hoeings is done depending upon the soil types, texture, structure and climatic conditions of the locality.
The frequency of irrigation depends upon the type of soil and weather conditions. In general, for sandy soils with dry weather, the fields should be irrigated at least every other day if not more often at a rate of 1-2 inches per week. Plants have a higher demand for irrigation during pollination and fruit development.
Cucumber needs staking as it increases harvesting efficiency and yields, improves pest management, uniform fruit colour and reduce the incidence of soil diseases. It should be done before flowering.
Flowering/sex expression of the plant
Cucumber varieties are either monoecious or gynoecious in their flowering patterns. Formonoecious type plants, pollinators like bees play a very vital role in pollinating. Thus care must be taken to protect bees from nearby insecticide application as it will hamper the activity of the pollinators. It is best not to apply any of the insecticide during the pollination period. However, if the application is necessary, it is advised to apply any chemicals late in the day as the bees pollinate actively most in the morning and early afternoon.
Many cucumber hybrids are gynoecious which produces large numbers of female flowers and have fairly concentrated flowering period. The female flowers of the gynoecious varieties still need to be fertilized with pollen from male flowers, so a certain percentage of monoecious plants need to be planted along with the gynoecious plants to serve as pollinizers The green house cucumbers are usually seedless as they set and develop fruit parthenocarpically (without pollination).
Pest and Diseases
Pest and diseases are one of the factors that contribute to low yielding in cucumber. Cucumber beetles, pickle worm, fruit fly, mozaic viral disease, angular leaf spot, scab, gummy steam blight and black rot and downy mildew are some of the common pest.
Basic Techniques for Cucumber Pest and disease Control and Prevention:
Use clean seeds
Crop rotation with non-cucurbits
Rough and destruction of diseased plants
Early detection of insect and disease problems.
Use resistant or tolerant varieties where possible
Proper weed management.
Clean farm machinery and tools to prevent soil-borne pathogen spread.
The fruits can be harvested as quickly as 35-40 days from date of planting depending on the variety and weather conditions. Cucumbers are harvested at a variety of stages, from quite young to mature before seeds reach final maturity and harden depending upon the market demand. Frequent harvesting is necessary because fruits mature quickly. So, timely harvest keeps the plants in a productive mode since cucumber plants have a limit to the number of fruits they can support at any one time.
The fruits (slicing cucumbers) are harvested when the size ranges from 6-10 inches in length and 1.5-2.5 inches in diameter. It should be fresh, crisp, of medium size, well formed, uniform and of a deep green colour. A light green or yellow skin colour is an indication that the fruit is over mature for picking.
3.5-4 t/ac in 80 to 90 days after the date of planting.
Pre-cooling of cucumber under the shade is necessary before taking it to the packinghouse to maximize shelf-life. Decayed fruit should be discarded and then washed in chlorinated water.
The fruit should be firm, straight, uniformly smooth and deep green. It can be stored for 10-14days at temperatures 10-13oc with 95% relative humidity.
In some of the countries, cucumbers are waxed as the water loss from the fruit is reduced by
50%. Shrink-wrapping with polyethelene film, a common practice with greenhouse European cucumber, also extends fruit shelf life by preventing water loss.
For consumption, cucumbers are harvested when immature while for seeds purpose it is harvested when fully matured. As the seeds develop and reach full maturity, the fruits will eventually change its color to yellow and lose firmness. The fruits can also be left on the vine in the garden while they continue to mature and soften if the weather conditions are favorable. Mature cucumbers will pull easily from the vine when ripe.
Scoop out the cucumber seeds into a container with some water
Ferment (open container) it for 1-3days to remove the pulp from the seeds
After fermentation, add more water to the container and stir the mixture (discard the pulp and seeds that floats)
Rinse the seeds (viable) which have settled at the bottom of the container and dry it until it can be cleanly snapped in half.