How to grow cucumbers

How to grow cucumbers

Greenhouse cucumbers

                                                                                             

Savour the taste of summer with your own home grown cucumbers. Cucumbers are an essential ingredient for adding to sandwiches, delicious salads, and those long, cool summer drinks on the patio.

You don’t need a greenhouse to grow them as there are indoor types and outdoor varieties available. But it’s worth checking that you have the right type for your garden before you start sowing. You can grow cucumbers in the ground, in growbags and even in containers. View all of our cucumber seed varieties.

Different types of cucumber

mophead hydrangea
Growing cucumber plants is really quite easy once you understand that there are two main types available, and these need different treatment to produce a good crop. So to keep things simple, here are the main differences between greenhouse and outdoor cucumbers.

Greenhouse cucumbers
If you’re lucky enough to own a greenhouse then it’s well worth growing cucumbers indoors. Greenhouse cucumber plants produce long, smooth fruits similar to those that you find in the supermarkets. Greenhouse varieties don’t need pollinating - in fact, you should remove any male flowers to prevent pollination happening as this produces fruits with a bitter flavour. You can even buy ‘all female’ F1 hybrid varieties such as Cucumber ‘Flamingo’ which only produce female flowers, so you won’t need to worry about male flowers at all!

Outdoor cucumbers
Outdoor varieties are called ridge cucumbers. These varieties tend to be shorter with a rougher skin but have the advantage of being able to crop outdoors, so they are perfect for gardens without a greenhouse. Ridge cucumbers produce male and female flowers, and these need to be pollinated. This is not usually a problem though, as the insects outdoors will do the job for you.

Some ridge cucumbers are suitable for growing in the greenhouse if you prefer, but most gardeners would rather use their precious greenhouse space for greenhouse-type cucumbers. It’s important to never grow ridge cucumbers in the same greenhouse as an ‘all-female’ Greenhouse type as this will lead to cross-pollination, which can produce bitter fruits.

If you’re feeling adventurous you can even try growing white and yellow cucumbers or even ball shaped varieties. Some are ridge cucumbers while others need to be grown in the greenhouse. Always check before you sow them

CUCUMBER INTRODUCTION

The cucumber belongs to the Cucurbitaceae (gourd family). The cucumber belongs to the genus Cucumis of which there are 20 to 25 species found mostly in Asia and Africa. Only two Cucumis sativus (cucumber) and Cucumis melo (melon, muskmelon and persian melon) are of commercial importance in North America. It is an annual trailing or climbing vine usually with flowers of both sexes on the same plant(monoecious). Current market hybrids are produced on genetically gynoecious lines(all female blooms). Commercial seed lots have up to 10% of a monecious variety to provide sufficient pollen for fruit set. European greenhouse cucumbers set fruit without pollination (parthenocarpic). The cucumber is native to the northwest of India and has been cultivated there for at least 3000 years. The cucumber was known in France in the 9th century and was common in England in 1327.

          Cucumbers are very sensitive to cold temperatures and may be killed at 1°C. It has a minimum germination temperature of 16°C, an optimum germination range of 16°C to 35°C, with an optimum germination temperature of 35°C, and a maximum germination temperature of 40°C. Soil temperatures at planting must be at least 10°C for table cultivars and 13°C for gherkin cultivars. Planting must be delayed until all danger of frost is past. Windbreaks are essential for early production of this crop.

          A well drained loam to sandy loam soil with high organic matter with no frost pockets or problems with surface drainage is the ideal field situation. Wind protection, natural or artificial, is necessary.

           Slicing cucumbers, with the aid of plastics, are harvested from the field in early to mid July. Most of the field crop does not come on until early August. Slicing cucumbers average 15,000 kg per hectare with some yields as high as 22,000 kg per hectare. Due to market gluts in warm seasons not all of the crop is marketed. (2,500 doz per hectare to 5,000 doz per hectare). Pickling cucumber yields depend on the size of fruit harvested. (15,000 to 17,000 kg per hectare).

          Cucumbers are an important crop in the Atlantic area though market potentials may not be large. On the fresh side there is a strong demand for the product as it is a salad vegetable but processing cucumber markets have declined. The greatest potential would seem to be to extend the season by earlier production (use of plastics) and to look for speciality markets.

           Nutrient Content: Contains fair amounts of potassium, calcium and folate; and small amounts   of other nutrients including Vitamin C. Very low in calories. 6 slices contains 5 kilocalories.

Crop Growth and Sex Expression

  

Cucumber is an annual deep-rooted (ca. 3 ft) crop with tendrils and hairy

leaves. The plants may have an indeterminate, determinate, or a compact plant

habit. The compact growth habit consists of plants with shorter internode

length than plants with indeterminate or determinate growth habit. Optimum 

growth occurs between 70-75F (20-25C), with growth reduction occurring

below 60F (16C) and above 90F (30C).

Several flowering habits exist in cucumbers. 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 so-called "PF"

hybrids produce predominantly female flowers but also produce a small

number of male flowers. Often "pollination" plants are supplied to insure 

fertilization on "PF" types. Many cultivars grown in greenhouses such as 

European cucumbers are parthenocarpic. Parthenocarpic varieties require no 

pollination for fruit production. In fact, pollination of these cultivars causes

 an off-shaped appearance of the fruit.

 The first flowers of monoecious plants are staminate or 'male' followed by 

pistillate or 'female' flowers from which fruits are born. Sex expression in 

cucumber may be affected by several factors such as plant density, plant

stress, temperature, and light intensity. Reduced rates of female flowers in 

gynoecious cultivars may result from exposure to stress caused by high plant 

population densities, insect attack, wind damage, and combinations of low light

intensity and high ambient temperatures. The commercially available hormone

etephon, at 125-250 ppm, increases the production of pistillate or female

flowers in gynoecious cultivars. Cucumbers will interbreed with other

cucumber cultivars but not with melons nor squash. Some markets, such as the

Japanese market, prefer 'bloomless' fruits, or fruit free of the natural film or

powdery tissue that cover the skin of cucumbers and several other vegetables.

Cultivars

        Cultivar selection is one of the most important decisions made during the cproduction process. Selection of cultivars adapted to local growing conditions and seed quality are significant production factors that deserve careful planning and consideration. Desirable traits required for local cultivars include high productivity, high fruit crispness and firmness, and resistance to watermelon mosaic virus, zucchini mosaic virus, cucumber mosaic virus, powdery mildew, and angular leaf spot (Figure 1). As a standard for fruit quality the market still relies on the old 'Burpee Hybrid' first released in 1945 and which included >75% of cucumbers grown locally in the 1960s. 

         Newer commercial cultivars are available with resistance to important diseases such as angular leaf spot, anthracnose, cucumber mosaic virus, watermelon mosaic virus, zucchini yellows mosaic, downy mildew, powdery mildew, and scab. As described in the previous section, hybrid cucumber cultivars may be monoecious, gynoecious, or parthenocarpic. Parthenocarpic cultivars will produce seedless fruit in the absence of bees and pollination during the crop growth cycle. If bees are present for pollination, parthenocarpic plants will yield normal seeded fruits but fruit may be off-shaped. 

       Cultivars adapted to Hawaii include:

        Table 1. Cultivars adapted to Hawaii

        Western Slicing Types Fruit Length Fruit Diameter

        (inches) (inches)

        Burpee Hybrid II 8 2-1/2

        New Market #2 10 2-1/2

        Sweet Slice Hybrid 1 1 2-1/2

        Lani Hybrid (UH cultivar) 9 2-1/2

        Milo Hybrid* 8 2-1/2

        Dasher II (gynoecious) 8 2-1/2

        Sakata #69 8 2-1/2

        Slicemaster 8 2-1/2

        Slicing Oriental types (monoecious with an upright habit):

        Progress Hybrid-- 10 2

        Tasty Gem Hybrid-- 10 2

        Spring Swallow 7 1

      * (UH cultivar, indeterminate monoecious)

    Promising cultivars in Hawaii based on trials in Oahu include Genuine and Spring Swallow.    Other for-trial cultivars include Soarer, Southern Delight, Pegasus, Green Knight, Tokyo Slicer, Conquistador, and Brocade.

    

FERTILIZER RECOMMENDATIONS

      Soil Type

      Cucumbers are adapted to a wide variety of soil types which have good                 drainage and adequate soil-holding capacity.

        Optimum pH

   Cucumbers don't perform well on acid soils but do well under slight acidity. The optimum pH is 5.5-7.0. In general, if the soil pH is below 5.8 and the available soil calcium is less than 2,000 lbs. per acre, apply 2,000 lbs. per acre (4.5 lbs./100 square feet) of agricultural lime 8 to 12 weeks before planting. However, some Hawaiian soils may require considerably more lime. Liming to a pH of 7.2 to 7.5 plus the use of nitrate-nitrogen fertilizer sources help to reduce incidence of Fusarium wilt, Fusarium oxysporum in the field. Micronutrient availability may be reduced at a pH above 6.5.

Nutrient Rates and Placement

    Fertilizer applications should be based on crop nutrient demands and stage of crop growth. Tissue and soil analysis help to determine how much fertilizer to apply to complement the nutrient levels already available in the soil. Soil samples should be taken and appropriate fertilizers added as recommended by University of Hawaii soil scientists for the particular soil type. If the soil series is not known, growers should supply ample information about the origin of the soil sample so that the soil series can be determined through soil survey maps. Excessive fertilizer rates beyond crop needs may result in salt buildup, phytotoxic effects on plant growth, ground water contamination, delayed harvest due to excessive foliage growth, and capital losses due to purchase of unneeded fertilizer. Cucumbers tolerance to salt build-up in the soil ranges from moderate to sensitive.

   Estimated rates of nutrient removal for N-P2O5-K2O-MgO-CaO in fruits, leaves and stems with yields of 10,000 lbs/Acre are 32-9-44-6-23 lbs/Acre, respectively. Over 80% of the total crop nutrient removal takes place during the fruiting stage of crop growth.

              

  

Greenhouse studies of fruit growth and nutrient uptake rates in the continental U.S. indicate that cucumbers respond better to nitrate than ammonium N fertilizer sources. This results in greater Ca, Mg, and K levels in the fruit. Recommended fertilizer rates for Hawaii are 1,500 to 2,000 lbs. per acre of 15-15-15 or similar N-P-K fertilizer. Band half of the fertilizer 3 inches to the side and 3 inches below the seed at planting. Side-dress one quarter of the fertilizer rate at 3-4 weeks after planting and the remaining quarter, 6 - 7 weeks later. With the onset of harvest, side-dress every two weeks with a 3:1 mixture of sulfate of ammonia (21% Nitrogen): muriate of potash (61% potassium) or a 1:1 mixture of urea (46% nitrogen): muriate of potash at a rate of 200 lb per acre. Since N and K tend to leach, apply additional fertilizer after a heavy rain.

  On soils very low in available phosphate, apply 1,500 lb/Acre of treble super phosphate (47% phosphorus) or 1,500 lb/Acre of monoammonium phosphate (11-52-0). If both lime and phosphates are required, both should be incorporated together 8 - 12 weeks before planting.

Potassium improves fruit deep green color, firm flesh, shape, and overall yields.

   Magnesium is required in cucumbers to help obtain a deep-green fruit color. Magnesium deficiencies will be intensified in fields which have received high N or K fertilizer rates. For soils low in magnesium, apply magnesium sulfate (epsom salt, 9.8% Mg.) or its equivalent at 150 - 500 lbs/Acre. Soil magnesium deficiencies can also be corrected with periodic light dolomitic limestone applications.

   Cucumber's nutrition program should be tuned to achieve maximum yields and optimum market quality. For example insufficient potassium will result in misshapen fruit or "bottlenecks", and low nitrogen restricts growth, modifies the length-to-diameter ratio of fruit, reduces fruit set and color development. The symptoms listed in Table 2 should be helpful to help diagnose specific deficiencies. However, be aware that abnormalities such as those caused by root rot and nematode infections may produce similar symptoms in plants.

      Table 2. Common Nutrient Deficiency Symptoms in Cucumber

      Nutrient Deficiency Symptoms

   

Nitrogen Mature leaves yellowish green to yellow; stems slender, hard and fibrous; fruits light in color, pointed at blossom end; Stunted roots turn a brownish color and then die. Phosphorus Mature leaves change from a dark to dull green; Stems slender; Fruits dull green to bronze.

       Potassium Mature leaves bluish green near veins,

  

   Bronzing and necrosis of leaf margins; Young leaves are puckered or crinkled; Fruits constricted at stem end; Plant growth slow.

       Magnesium Plants are small and appear weak;

center-veinal chlorosis on mature leaves, veins remain green; Mature leaf edges brittleand ragged; Yields are low and quality of fruit is poor.

   Calcium Misshapen fruit; Water soaked and necrotic

  lesions on blossom end; "Pillowy" fruit disorder. Reduced shoot, root and fruit growth.