Growing Water Spinach (Kangkong)Note Number: AG0900Published: March 2002Updated: August 2010Water spinach (Ipomea aquatica...
Practically all parts of the young plant are edible, although the shoot tips and younger leaves arepreferred. Water spinac...
Water spinach can also be raised from stem cuttings, 30-40 cm long, taken from the young growth justbelow a node, and plan...
on plant vigour and temperature. About 40 tonnes/ha can be harvested from three or more cuttings in ayear.Rapid and carefu...
1 Spring StreetMelbourne, VictoriaThis publication is copyright. No part may be reproduced by any process except in accord...
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Growing water spinach

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Growing water spinach

  1. 1. Growing Water Spinach (Kangkong)Note Number: AG0900Published: March 2002Updated: August 2010Water spinach (Ipomea aquatica) is of East Indian origin and a member of the Convolvulaceae (morningglory) family. It has long, jointed and hollow stems, which allow the vines to float on water or creepacross muddy ground. Adventitious roots are formed at nodes which are in contact with water or moistsoil. They exude a milky juice, and are white or green, depending on variety. Water spinach has norelationship with common spinach, but is closely related to sweet potato (Ipomea batatas).IntroductionWater spinach is an herbaceous aquatic or semi-aquatic perennial plant of the tropics or subtropics.Leaves are flat, and vary in shape depending on variety, from heart-shaped to long, narrow and arrow-shaped. Narrow leaves are 1-2.5 cm wide and 20-30 cm long. Broad leaves are up to 5 cm wide and 15-25 cm long.The large, attractive flowers have the typical open, trumpet shape of convolvulus or bindweed flowers.They are usually white, sometimes with a pinkish centre. Wild forms may have purple or mauve flowers.The leaves have a very pleasant, mild, sweet flavour and a slightly slippery texture, which contrast whencooked with the crispness of the stems. The Chinese consider the white-stemmed forms betterflavoured and tenderer than the green. Like many other leafy vegetables, water spinachs leaves arevery nutritious, being rich in vitamins and minerals. They are also a mild laxative.There are two major cultivars of water spinach, Ching Quat (known as “green stem”) – this has a narrow, pointed leaves and white flowers and is adapted for moist soils. This can be grown in beds, provided there is always plenty of moisture. Pak Quat (known as “white stem”) – this has broad, arrow-shaped leaves and pink flowers. It is adapted to aquatic conditions and also called “Water Ipomea”.Water spinach has different names according to language and dialect. Water convolvulus, Kang cong andSwamp cabbage are some alternative names in English. It is known in Mandarin as kong xin cai (emptyheart/stem vegetable); ong tsoi and weng cai (pitcher vegetable) in Cantonese, kang kong in Filipino andMalasian and in Japanese as Asagaona (morning glory leaf vegetable).Uses
  2. 2. Practically all parts of the young plant are edible, although the shoot tips and younger leaves arepreferred. Water spinach is consumed differently in Western and Chinese cuisines. Water spinachdeteriorates rapidly once picked, so must always be used very fresh. The leaves can be used whole, orcut into smaller pieces. Like ordinary spinach, the stems require slightly longer cooking than the leaves.The Cantonese exclusively stir-fry it.Coarse stems and leaves are often used for animal fodder.Growing conditionsClimateWater spinach is not adapted to climates with mean temperatures below 10 °C and the optimaltemperature is around 200C – 300C. It is grown year-round in the tropics. Flowering occurs under short-day conditions and commences from mid-summer onwards. Water spinach is perennial in warmclimates, but an annual under cooler growing conditions. It tolerates very high rainfall, but not frost.Water spinach can be grown outside in summer. In cool areas, it can be grown in unheated greenhousesin summer, but will require heated greenhouses for a spring crop. It prefers full sun but where summertemperatures are very high, it is sometimes grown as a ground cover beneath climbing plants. Waterspinach should be sheltered from strong winds.Soil and soil preparationWater spinach requires fertile soils rich in organic matter. Overwatering can leached out readilyavailable nutrients and will affect yield. Therefore slow releasing fertilizers are recommended to avoidthe loss of nutrients. The most suitable soil pH ranges from 5.5 to 7.0.Crop managementSowing and plantingIn moist soil culture, the crop is grown on raised beds 60-100 cm wide. Seeds are sown directly ornursery-grown seedlings are transplanted into the beds. Seed should be no more than 2 years old andcan be soaked for 24 hours before sowing to encourage germination. Soil temperature requirement forgermination is 20 °C.When rainfall is low, frequent heavy irrigations are necessary for high quality shoots.To produce strong seedlings, seed should be sown 5-10 mm deep in trays with potting mix deep enoughto allow the plants to develop a good root system. Transplanting should take place when plants are 10-15 cm high, with four true leaves. Highest yields are obtained by spacing plants at 15x15 cm. They canalso be grown in rows about 30 cm apart with plants at 20 cm spacing within rows.Propagation from cuttings
  3. 3. Water spinach can also be raised from stem cuttings, 30-40 cm long, taken from the young growth justbelow a node, and planted about 15 cm deep. To ensure earliness, growers in China sometimes lift rootsat the end of the season, store them carefully in winter, and plant shoots from them in spring.For aquatic culture, cuttings from the broadleaved cultivars are transplanted into puddled soil, similar tothe planting of rice in paddies. The cuttings are about 30 cm long with seven to eight nodes, and areplanted 15-20 cm deep and spaced 30-40 cm apart.IrrigationFor aquatic culture after planting the land is flooded to 3-5 cm in depth and the water is kept flowingcontinuously. In moist soil culture, irrigation should take place every 1-2 days for high quality shoots ifrainfall is low.NutritionBefore planting, the crop must be given sufficient nutrients to produce quality spinach. After the plantsare established, nitrogen in the ammonium form should be applied at the rate of 40-50 kg/ha, then thewater level is raised to 15-20 cm depth. Plants respond well to nitrogen, but over-feeding must beavoided because for high nitrate concentrations in the leaves and stems can result which is undesirable.Regular applications of an organic liquid fertiliser should occur every 2 weeks or so for best results.Liquid fertilisers are usually diluted before application the plants.Pests and DiseasesThe main fungal diseases, which effect water spinach, are stem rot (Fusarium oxysporum) and black rot(Ceratocystis fimbriata). For prevention of fungal diseases strategies such as use of clean land and rotatecrops every third or fourth year, carefully select stems for propagation that are disease freeInternal cork, chlorotic leaf spot, yellow dwarf and russet crack are viral diseases which can also affectwater spinach.The most important insect pests are leaf beetle, aphids, and wire worm.HarvestWater spinach should be harvested before it flowers. In the semi aquatic type, the crop is ready forharvest 50-60 days after sowing, when entire plants are pulled, washed and bundled. More than oneharvest can be taken if shoots are cut above ground level, allowing secondary shoots to grow fromnodes below the cut.In the aquatic type, the first harvest can be made after about a month of good growth. The frequency ofharvesting will depend on the growth rate of the crop. The upper part of the main shoot, about 30 cmlong, is cut about 5 cm above water level. Bundles of 8-10 shoots are marketed. Removal of the mainshoot stimulates horizontal shoot growth. These new shoots can be harvested in 4-6 weeks, depending
  4. 4. on plant vigour and temperature. About 40 tonnes/ha can be harvested from three or more cuttings in ayear.Rapid and careful post-harvest handling is required to minimise damage to the fragile crop, especiallydue to wilting caused by moisture loss. To prevent this, the plants should be harvested during thecoolest part of the day. After bunching, a fine spray of cold water should be applied, and the leaves keptin a cool place away from the wind.Leaves are usually sold in 500 gram bunches in the markets.Further ReadingDahlen, M. (1992) A Cooks Guide to Chinese Vegetables, The Guide Book Company Ltd, Hong Kong.Hackett, C. and Carolane, J. (1982) Edible Horticultural Crops. Academic Press, Australia.Larkcom, J. (1991) Oriental Vegetables: The Complete Guide for the Gardening Cook. John Murray Ltd.London.Nguyen, V. Q. (1992)Growing Asian Vegetable, Agfact H8.1.37, NSW Agriculture.Rubatzky, V. (1990) Specialty and minor crops Handbook; Chinese Water Spinach, Swamp Cabbage, KangKong, Water Convolvulus. The small Farm Centre, University of California. USA.Waters, C. T., Morgan, W.C. and Mc Geary, D.J. (1992) Oriental Vegetables: How to Identify, Grow andUse. Government of Victoria. Department of Agriculture, Agmedia, Melbourne.Yamagushi, M. (1983) World Vegetables: Principles, Production, and Nutritive Values. AVI PublishingCompany, USA.Contact/Services available from DPICorrect diagnosis is essential for effective pest and disease control. A commercial diagnostic service isavailable at the DPI Knoxfield.For further information, phone Crop Health Services on (03) 9210 9222 or fax (03) 9800 3521.For further information on registered chemicals, phone DPI Customer Services Centre on 136 186.AcknowledgementsThis Agriculture Note was prepared by the Farm Diversification Service (Bendigo), Murat Top and BillAshcroft in March 2002.It was reviewed by Neville Fernando and Rob Dimsey, Farm Services Victoria in August 2010.ISSN 1329-8062Published and Authorised by:Department of Primary Industries
  5. 5. 1 Spring StreetMelbourne, VictoriaThis publication is copyright. No part may be reproduced by any process except in accordance with theprovisions of the Copyright Act 1968.The advice provided in this publication is intended as a source of information only. Always read thelabel before using any of the products mentioned. The State of Victoria and its employees do notguarantee that the publication is without flaw of any kind or is wholly appropriate for your particularpurposes and therefore disclaims all liability for any error, loss or other consequence which may arisefrom you relying on any information in this publication

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