Types Of Vegetables Gardening.docx

Types of vegetables gardening Dr K K Misra, Dr Khushbu Kholiya, Rimi Mandal and Ashish Kumar

Vegetable farming can be classified into various types depending on the acreage cultivated, method of cultivation and purpose of vegetable production. Based upon these facts vegetable cultivation is divided into the following types of gardens. Kitchen Garden Kitchen garden or home garden is defined as growing of vegetable crops in the residential houses or in their vicinity to meet vegetable requirements of the family throughout the year. To produce insect and disease free vegetables, commercial growers often resort to indiscriminate use of pesticides that might lead to serious health hazards. Under such Circumstances raising one’s own kitchen garden to produce healthy and residue free Vegetables have got an added advantage. The most fundamental determinant of success of a Kitchen garden is its location. As the family members perform most of the garden operations in their spare time, the location should preferably be in the backyard of the house. Secondly it Should be near the water source. The kitchen garden should never be located in a shady place rather it should receive sun light for most part of the day. However in cities, there is hardly any choice as regards size, shape and location is concerned. Under such situations, whatever Space is available has to be utilized. If the garden is located outside the house a live fence all around be raised to protect the garden. The following principles should be considered while designing a kitchen garden; () Land should preferably be selected in the backyard of the house. Rectangular shape is Preferred to the square one. (ii) The lay out should allow access to all parts of the garden. (iii) Quick growing fruit trees e.g. papaya, kagzi lime etc. should be located on north side of the garden so that they do not shade other crops. (iv) Climbers e.g. cucumber, pea etc. can be trained on the fence. (v) Several sowings or succession of sowings of one particular crop e.g. fenugreek,

radish, okra, cauliflower, etc., at short intervals should be done to ensure a steady supply of vegetables for a longer period (vi) Ridges which separate the beds should be utilized for growing root vegetables e.g. radish, turnip etc. (vii) Inter-space of slow growing crops e.g. cauliflower, cabbage, eggplant etc. should be used for quick growing crops like turnip, radish, leaf beet etc. Selection of crops for kitchen garden depends on two factors i.e. size of the garden and choice of the family. Only those vegetables are grown which are suited to the region and produce satisfactory yield. The cultivars should be selected according to the suitability for the region and season. Preference is given to those crops where freshness is important from the edibility and food value point of view. Such crops include tomato,, beans, pea, salad crops, leafy vegetables etc. Tentative monthly programme for kitchen gardening in north Indian plains January: sow/ plant muskmelon, watermelon, coriander, lettuce, spring potato, European radish and late cauliflower (if not planted earlier). February: sow/plant okra, luffa, cucumber, snapmelon, amaranth, bottle gourd, Pumpkin, summer squash, bitter gourd, European radish, leaf beet, pointed gourd, eggplant, And tomato. March: repeat showing of okra, amaranth and leaf beet. Sow cowpea, cluster bean, roundmelon and other above-mentioned crops if not sown already. Plant elephant foot yam, peppermint and artichoke. April: continue with the crops sown in March. May: Sow rainy season okra, luffa, radish, cucumber, bottle gourd, bitter gourd and pumpkin. June: Continue with the crops sown in May and also sow early cauliflower, cowpea, cluster bean, Dolichos bean, round melon, sweetpotato and radish. July: Sow early cauliflower, cluster bean, bottle gourd, okra, tomato, Dolichos bean, and eggplant. Also sow radish, leaf beet and cauliflower of second group. August: Plant, cauliflower, leaf beet, turnip (Asiatic type), and carrot. Also sow cabbage, fenugreek, knol-khol, Chinese cabbage, onion bulb sets (kharif onion), beetroot and coriander.

September: sow early pea, coriander, onion bulb sets (kharif onion), radish, carrot, turnip, celery, beetroot, Dolichos bean, cauliflower (late group), cabbage, knol-khol, lettuce, leaf beet, potato and pea. October: Sow/ plant parsley, lettuce, parsnip, potato, turnip, beetroot, radish, garlic, pea, French bean, onion and knol-khol. November: sow the crops mentioned for October. Also sow pea, tomato and spinach. December: Sow tomato, spinach, late cauliflower and pea, if not planted already.

Model of Vegetable Nutrition Garden The suggested model of ‘Vegetable Nutrition Garden’ has several modifications over the conventional Kitchen Garden. The new model can fit in urban and peril-urban households where limited space is available for growing vegetables. The crop sequences are selected in such a way that the garden remains occupied throughout the year. The crops and their varieties are scientifically selected for their rich nutrient contents and least pest and disease problems, thus minimizing the use of pesticides. As per the given plan, up to three annual vegetables per year can be grown on the same piece of land. Layout and planning of 6

6m

Vegetable Nutrition Garden is given in Fig . requirement of vegetables recommended for the garden is given in Table 3.1. The model produces about 300 kg of vegetables annually, enough to meet dietary allowance of an average sized family consisting of two adults and two children.

BLOCK A

BLOCK B

BLOCK C

BLOCK D

BLOCK E

TABLE 3.1 Spacing requirement of vegetables grown in Vegetable Nutrition Garden Name of Vegetable

Spacing (cm)

Name of Vegetable

Spacing (cm) Bottle gourd 15

80 *

45

Mint

7.5

Chinese cabbage /

15

Onion Cabbage 30

15 20/45

30

Radish 80

45

15 20 / 60

Cauliflower 15

45 10 / 45

15

15/80

20/45

30

45

30/ 45

60

7.5

Basella / Arvi

45

Broccoli

15

10

Carrot

45

30

Cucumber

15

5

30

15

7.5

30

Palak

Tomato

30

Cowpea 60

Okra / Bitter gourd

30

Amaranthus

80

Pea

20

Methi

80

10

l 45

Chili

45

Vegetable mustard /

45

Lab lab/Turnip

45

30

7.5

Brinjal

20

Kang kon / Sweet potato

30

Coriander

45

7.5

30

Lettuce

30

Long melon

30

Garlic 20

7.5

Capsicum

30

Sponge gourd

80

45

3.2. MARKET GARDEN Farms those produce vegetables for supply to consumers in the local market is called a market garden. Since people living in cities usually have neither the space nor the time to devote to gardening, there developed a tremendous demand of vegetables. The ultimate aim of vegetable production in market gardens is their quick disposal in nearby market. Hence, nearness to market with a reliable transport should not be ignored. For a long time, market

gardens were located at a distance of 10-15 km from the cities. However, with the expansion of cities and improvement in road and transport network, such gardens are located even beyond 30-40 km from main cities. The farmers adopt intensive cultivation to earn maximum Profit from small to medium land holdings. Therefore, the fertility of soil needs to be replenished with the application of organic manure etc. Municipal compost and sever water are also important sources of restoring soil fertility. To fetch remunerative price in the market, farmers adopt cultivation of early/ off-season vegetables. However, the grower needs to be well trained to succeed in this specialized type of farming. The grower also needs to develop good marketing skills as no middleman is involved in disposal of the produce. As intensive as well as extensive vegetable culture characterizes market gardens, a lot of green matter is added to the soil every year. Decomposition of the green matter and the compost added to replenish depleting soil fertility slowly but surely changes the soil reaction to acidity. It is therefore important to get the soil tested periodically i.e. every three or four years. Application of lime is desirable if the soil pH turns acidic. TRUCK GARDEN The word truck has been derived from French word ‘o barte’ meaning ‘to barter’. This is an extensive type of farming where one or two crops are grown in large quantities to feed the distant markets that are located hundreds of kilometres away from the growing areas. Since farms are located away from the consumer markets, middleman is involved in marketing the produce. Due to large-scale production, farming is usually mechanized. In this type of garden, varieties should possess special attributes to withstand distant transportation. This is particularl true with the perishable vegetables. For example, Punjab grown tomatoes, especially variety Punjab Chhuhara, were transported to as distant places as Mumbai. Similarly, Punjab Sunehri variety of muskmelon is transported from Punjab to Srinagar in J and K. Vegetables like pea, tomato, cauliflower etc. grown in the moderate climates of Solan and Shimla in Himachal Pradesh are transported to the neighbouring states of Punjab, Haryana and Delhi. Non-perishable vegetables like potato, onion,, pumpkin etc., do not suffer transport losses and can be transported to any part of the country. GARDEN FOR VEGETABLE FORCING The word forcing designates growing of vegetables out of their normal or usual growing season. Most of vegetables are perishable and cannot withstand long storage. Therefore,

vegetable forcing has developed to supply farm fresh vegetables to the consumers for most part of the year. In developed countries like the USA, Japan, Canada and parts of Europe, glass house structures are constructed for vegetable forcing. In a glass house, temperature, light, carbon dioxide and relative humidity are controlled artificially and the technology is expensive. Cultivation of vegetables under protected conditions ensures better quality, uniformity and extended availability period. The cost of production and subsequent sale price is out side the reach of a common Indian consumer. Therefore, the growers are not yet prepared to enter into this costly venture. On the other hand, some cheap but efficient polythene structures have been designed to produce summer vegetables in winter months. In winter season, 4-6 C higher temperature can be maintained inside the poly-house without any heating provision, which provides better conditions for plant growth. During extreme summer, desert coolers and sprinklers are installed to reduce the temperature by 5-10 C. Honeybee boxes are placed inside the poly-house to facilitate pollination in cross-pollinated vegetables. If poly-house is small, pollination is done manually. Vegetable forcing can also be adopted without any provision or structure when specific production techniques or varieties of certain vegetables bred only for growing in the offseason are available. The examples are; Forcing in Cucurbits Cucurbits, especially muskmelon, watermelon, cucumber etc. are forced to grow early in polythene bags of 10

15 cm size and 100 gauge thickness. Sowing is done in end of January

even when winter is severe in north Indian plains. Pre-sprouted seeds are used to boost early emergence. Transplanting of seedlings in early March gives fruits about 20 days earlier than the direct sown crop. In addition to producing higher early and total yield, transplanted crop escapes the attack of red pumpkin beetle. Another method of producing early cucurbits is riverbed cultivation. The available weed free fertile soil in river beds provide ideal conditions for cultivation of a number of cucurbits including muskmelon, watermelon, longmelon, cucumber, bitter gourd, ash gourd, pumpkin, bottle gourd and sponge gourd. Tomato, eggplant, carrot, radish and spinach are also grown successfully. Trenches are dug 2-3 m apart in late October and most of cucurbits are sown in November or December. Due to low temperature, pre-sprouted seeds are used and young seedlings are protected from frost. Seedlings of tomato, eggplant and are transplanted in

September-October. Forcing in Tomato Normally tomato is transplanted into the field in February to avoid cold and frost injury to the crop. However, by adopting remedial measures, the crop can be sown in end October and transplanted in early December. This crop is protected from frost and chilly winds during winter by erecting sarkanda (wild Saccharum) or polythene cover. The cover is erected at an angle of approximately 45 . As soon as the risk of frost is over, the cover is removed. December planting not only advances fruit availability but also increases total yield due to extended fruit setting period. Another off-season crop of tomato is panted in mid-August to mid-September in north Indian plains. The crop matures in December-January. However, the varieties to be cultivated in this season should be resistant to leaf curl virus. Kharif Onion Production Kharif onion production technology has been developed to supply onion in winter months when the stocks of the normal crop harvested in April-May are exhausted. Agrifound Dark Red (ADR) is the most suitable varieties for kharif onion production. For kharif crop, seed is sown in mid March and seedlings are uprooted in end June when bulbsets attain pencil size thickness. These bulbsets are stored in ventilated rooms and are transplanted in mid August. The crop is ready for harvesting in early December. Role of Varieties in Vegetable Forcing Other than adopting standardized technology for vegetable forcing, selection of appropriate variety is a crucial factor. Take for instance cauliflower, a winter season vegetable. Except two or three months of intense heat, its curds are available throughout the year. This is possible due to proper selection of the variety. Early Kumari is a known variety of cauliflower capable of tolerating high temperature. Similar is the case in radish. Pusa Chetki, a heat tolerant variety, is recommended for the summer season and Pusa Himani, a temperate type, is recommended for spring season. In pea, Hara Bona, Arkel and Matar Ageta 6 have the potential to tolerate high temperature. With the development of leaf curl virus resistant varieties like Punjab Varkha Bahar 1 and Punjab Varkha Bahar 2, it is now possible to extend tomato cultivation to the rainy season which otherwise was not possible due to severity of the disease. VEGETABLE GARDEN FOR PROCESSING

The type of farming that produces vegetables with a sole objective of supplying to the processing industry is termed as vegetable garden for processing. Vegetable production for processing mainly canning, freezing and dehydration is distinct from fresh market vegetable production. The vegetables meant for processing are grown exclusively in field under naturally occurring conditions. A significant quantity of vegetables meant for fresh market consumption especially tomatoes, bell pepper, cucumber and lettuce is grown in green houses where the environmental conditions are artificially manipulated. For processing, only one or two varieties of one or two crops are grown on a large scale to produce in bulk. The farming is generally mechanized and away from the cities. The varieties are selected in such a way that there is a continuous supply of raw material to feed the processing units for a longer period. There are specific varieties for processing purposes. For example, in tomato recovery of processed product is determined by the TSS (total soluble solids) content of fruits. The processing varieties, therefore, ought to possess higher TSS content. The pH of fruits ranges between 4.0-4.5 to restrict the growth of thermophyllic organisms. Besides, the fruits have a balance acid: TSS ratio to impart desirable flavour to the product. The fruits are firm to withstand distant transportation, bulk handling and mechanical harvesting. The fruit colour is deep red (high in lycopene) to impart attractive colour to the processed product. Otherwise, the processors add synthetic dyes, which may prove health hazardous. Further, there are different varieties for different processing methods viz. canning, freezing, paste, powder, juice, etc. Gardens for vegetable processing are very common in countries like the USA, Canada, Australia and some of the European countries because of the well-established processing industry. This type of farming is not very well developed in India. Vegetables meant for processing are grown on contract basis. For example, tomato and are commercially grown in Punjab for processing. Disease free seedlings of the suitable varieties are raised and supplied to the growers by the processing units. Farmers raise the crop and supply the produce to the processing units under pre-decided terms and conditions. Some of the units engaged in processing include Hindustan Levers, Zahura (tomato), Nijjar Agro, Nijjarpura (tomato and) and PepsiCo, Channo (), PAGRO Foods Ltd., Fatehgarh Sahib, etc. VEGETABLE GARDEN FOR SEED PRODUCTION Seed production is a highly specialized farming and only trained grower possessing technical

know-how succeeds in such a pursuit. This type of farming is adopted in large areas for the production of vegetable seeds. Locations prone to natural vagaries e.g. rain at the time of crop and seed maturity are avoided for seed production. Similarly, areas those are infested with diseases especially seed borne ones are also excluded from seed production. Sowing time of seed crops is adjusted in such a way that it escapes the infection by the disease causing pathogen. For example, seed potato produced in mid-hills of H.P. etc. is free of tuber borne viruses due to absence of the insect vector. In north Indian plains, disease free seed potatoes are produced from mid. October to end December through the ‘Seed Plot Technique’. This period witnesses lowest population of aphids, an insect vector. To maintain genetic purity, the field for seed production should be free from volunteer plants. In cross-pollinated crops, normally one crop variety is planted at one location. Beehive boxes are also placed inside the seed production blocks to enhance pollination and consequently seed yield. Insecticides are sprayed only during morning and evening hours when bees are inactive. A proper isolation distance between varieties of the same crop and of other crops those are cross-compatible, is maintained to produce true-to-type seed. The isolation distance depends upon the crossing behavior (self, often or cross-pollinated) of the crop and category (breeder, foundation or certified) of the seed. Off-type plants from the seed production block are removed at vegetative, flowering and fruiting/ pod formation stages. Owing to the diverse agro-climatic conditions, strong production infrastructure, abundant manpower and market opportunity, India holds tremendous promise for vegetable seed exports especially of hybrid seeds. 3.7. VEGETABLE GARDEN FOR EXPORT General Agreement on Trade and Tariff (GATT), formerly known as the World Trade Organization (WTO), has provided new opportunities to India for the export of vegetables. Lately, India is emerging as a major exporting country for a number of vegetable crops. Total export of vegetables is of the order of over R 4867 crores during 2015-16. Of these, onion accounts for more than 77 per cent. Vegetables being exported from India include onion, potato, okra, baby corn, tomato, pickling cucumber,, French bean, bitter gourd and bottle gourd. Among fresh vegetables, okra accounts for 60 per cent of the export. The area under pickling cucumber for export is increasing in Karnataka, Andhra Pradesh and Maharashtra. The major importing countries of okra are West Asia, West Europe and the US.

Among processed vegetables, major demand is for dehydrated onion, garlic and processed cucumber and gherkin. The Agricultural and Processed Food Products Export Development Authority (APEDA) has identified asparagus, celery, sweet pepper, sweet corn, pea and cherry tomato among nontraditional vegetables for export. For export, the product should be true-to-type as per the declared variety and standards, uniform in shape, size, colour and free from chemical residues. Vegetables should be properly graded and packed in good quality boxes of appropriate sizes. The requirement of variety of vegetable and its quality for Europe, Japan, Australia, and USA etc. is different to that of Gulf countries and the Southeast Asian countries. Vegetable garden for export must meet the quality standards of the importing countries. Some of the specific requirements of vegetables for export are listed in Table below. ORGANIC VEGETABLE GARDEN The conventional farming approach is to apply important nutrients directly into the soil solution at rates and times to satisfy plant requirements. Synthetic chemicals are used to control insect-pests and diseases. Chemicals are also used to affect physiological processes and conditions such as flowering, fruit setting, colour development and ripening. However, injudicious use of chemical fertilizers especially nitrogenous fertilizers leads to degradation of the earth environment and outbreaks of aphid and other sap-sucking pests. Insecticides also kill natural enemies of weeds; fungicides kill soil micro-organisms that control nematodes; and both insecticides and fungicides reduce earthworm population, thus lowering soil fertility and water infiltration rates. Nevertheless, human survival depends on agriculture production

Export quality requirements of different vegetable crops Crop

Desirability

Okra

green, tender, 6-9 cm long

Chilli

green, 6-7 cm long

Bitter gourd

green, 20-25 cm long with short neck

Bottle gourd

light green, straight, cylindrical in shape, 25-30 cm long

Pickling cucumber Tomato round

green, small sized, weighing 160-300 fruits per kg , medium sized, deep red colour for Middle East and cherry

tomatoes for Europe French bean Onion

straight 10-12 cm long, round green pods (large) () 7-8 cm in diameter, yellow/ brown in colour, round

or spindle shaped for Japan and European countries (ii) 4-6 cm diameter, light to dark red colour, round shape, strongly pungent for Gulf and South-East Asian countries (iii) 3-4 cm in diameter, light red and round shape for Bangladesh (small) Multiplier onion Garlic white round,

() 2-3 cm in diameter, dark red and round in shape 2.5-3.5 cm sized bulblets of bright red colour 5 cm and above, bigger cloves 10-12 mm and above with10-15

in number For Bangladesh and Sri Lanka, 4-5 cm size bulbs are also accepted Potato white,

oval, 4.5-6.0 cm size

Bangladesh demand red types; and Iraq and Iran demand yellow flesh potatoes being improved and earth’s environment being sustained. The concept of organic farming is to feed the soil and not the plant. Organic farming, therefore, is a production system that avoids or largely excludes the use of synthetically compounded fertilizers, pesticides, growth regulators etc. To the maximum extent feasible, organic farming systems rely upon crop rotation, crop residues, animal manure, green manure, legumes, off farm organic waste, mechanical cultivation, mineral bearing rocks and aspects of biological control to maintain soil productivity and tilth, to supply nutrients and to control insects, diseases and weeds. The crops and the crop varieties are selected carefully as some crops are less prone to the attack of insects and diseases and thus can be grown easily without any chemical sprays. These crops include beet, carrot,

onion, garlic and leafy vegetables. However, some losses/ damages caused by insects, diseases and weeds are expected in Organic Vegetable Gardens. There are many techniques that will reduce the need for synthetic pesticides and improve soils without chemical fertilizers. Nutrient Management in Organic Vegetable Gardens Application of manures, rock minerals, bio-fertilizers and crop rotation with legumes and catch crops are an integral part of Organic Vegetable Gardens to maintain nutrient status the soil. Crop rotation plays an important role not only for weed control and soil management but also for the supply of nitrogen. Green cover of soil is maintained as much as possible with green manure and under sowing. The practice increases soil organic matter, soil nitrogen, as well as other nutrients. This also helps to reduce soil erosion and leaching of nutrients. Bio-fertilizers fix atmospheric nitrogen with the help of specialized soil micro-organisms. Micro-organisms e.g. bacteria, blue green algae and some fungi are either free living in soil or symbiotic with plants and directly or indirectly contribute towards the nitrogen nutrition of the plants. In areas where legume vegetables are being sown for the first time, seed is treated with Rhizobium culture to ensure proper nodule formation and early growth. Rhizobia are naturally occurring soil bacteria that fix atmospheric nitrogen into the soil. They live in symbiosis with legume plants and are found in nodules on plant root system. There are different cultures for different crops. The culture emulsified in 10 per cent sugar (jaggery) solution is rubbed thoroughly to give a fine coating to the seed. Treated seeds are dried in shade before sowing. The non-symbiotic micro-organisms like nitrogen fixing cyanobacterium (Aulosira fertilissima) and non-nitrogen fixing cyanobacterium (Spirulina subsulsa) are helpful in fixing atmospheric nitrogen and release of unavailable nitrogen present in soil. Mycorrhizae fungi live symbiotically with crop plants. It obtains carbohydrates from the plants and in return supply nitrogen and moisture to the plants. Application of basic slag, rock phosphate and potash of magnesia supplies other plant nutrients. For example, limestone and marl supply calcium; gypsum supplies calcium and sulfur; rock phosphate supplies phosphorus and calcium; dolomite supplies calcium and magnesium; and basic slag supplies iron, calcium, magnesium and manganese. Gypsum as a source of calcium is preferred in soils where pH is high. Other trace elements are also supplied through various types of rock dusts e.g. basalt.

Alternative means of Insect-pests and Disease Control in Organic Vegetable Gardens Pest and disease control in organic vegetable gardens is accomplished through careful selection of crop varieties (resistant) that are adapted to the local conditions, cropping systems and tillage. Genetic (sterile insect technique), biological (natural enemies and insect pathogens), biotechnological (resistant gene transfer across species) and physical (microwaves, heat, cold etc.) are the other methods employed for pest and disease control. Some of the examples are: • Red pumpkin beetle is a serious pest of cucurbits. Growing of cucurbit seedlings in polythene bags to enhance maturity also helps escape the attack of red pumpkin beetle, a serious pest of direct sown crop. (Details see under Vegetable Forcing). • Net house technology is helpful in growing vegetables free of insect damage and insect transmitted diseases without chemical sprays. The technology is especially useful in crops like tomato, eggplant etc. where chemicals are repeatedly sprayed to guard against fruit borer. • Soil borne pathogens like Sclerotium rolfsii, causing collar rot of tomato, are controlled by soil solarization. For solarization to be more effective, the moist soil is covered with transparent polythene sheet in hot summer months. Double-layered polythene mulches are more effective than the single-layered ones. The practice is also effective against soil inhabiting nematodes. Mulches, both polythene and plant debris, serve as barrier against diseases like buckeye rot of tomato that is spread by soil splashing onto the plants. Mulches also reduce a number of soil insects like Colourado potato beetle and prevent decay of fruits touching the soil. • Use disease free seed especially to manage seed borne diseases. Rogue-out diseased plants as early as possible to check their spread to healthy plants. Other cultural practices followed to minimize diseases and insects include field sanitation, proper plant spacing, bed planting where ever possible, crop rotation with non-host crops, drip irrigation, vertical training of crops like tomato, beans, cucumber, bitter gourd, luffa etc. Training of plants e.g. tomato, beans and some cucurbits on fence or trellis improves air circulation thus minimizes chances of appearance of diseases and insects. This also minimizes contact of fruits with the infected soil and reduces chances of diseases like buckeye rot of tomato and other fruit decays. Keep the field

clean by removing plant debris and weed plants. This is important because many plant pathogens and insects survive on plant debris and weed hosts. • Increasing soil organic matter controls nematodes as micro-organisms attack them, which proliferate in high organic soils. Application of organic manures also helps in controlling common scab of potato by favouring micro-organisms antagonistic to the scab pathogen. Fertilization with compost suppresses the incidence of Colourado potato beetle in potato. • Handpick and destroy larvae of insects that appear sporadically. This method of control is very successful in small gardens and with large insects especially the caterpillars. Use strong water sprays to wash-off small insects e.g. aphid, thrip, whitefly, mite, etc. • Avoid watering, especially through sprinkles, in late evening hours to minimize occurrence of foliar diseases. • Soil insects like grubs, cutworms etc. are exposed by soil tilling and are picked by the birds. Young plants are protected from cutworms by placing a tinfoil collar around the plant stem at ground level. • Incorporated host plant resistance is an integral part of organic vegetable farming. Some of the commercial vegetable varieties possessing resistance to various insectpests, diseases and nematodes are listed in Table below • Grafting on resistant rootstocks is helpful to combat soil borne diseases, especially the wilts and the root knot nematodes. Use of grafted seedlings is also recommended in hydroponics culture of tomato, eggplant, pepper and cucumber. • Powdery mildew, a serious disease of cucurbits, is controlled by spray of cow milk @ 10 per cent twice a week or 20 per cent once in a week. Cow milk has more than onemode of action in controlling the disease. One, it directly affects the disease due to its germicidal properties and secondly, various salts and amino acids present in the milk act as a foliar fertilizer thus boosting the plant immune system. • Various plant extract based natural pesticides are affective against insect-pests and diseases. The three types of natural pesticides used are biochemical/ botanical, microbial and mineral based pesticides.

() Botanicals Nicotine sulfate: It is extracted from tobacco or related Nicotiana species and is effective against sucking pests like aphids, thrips, spider mites etc. Rotenone: It is resinous compound produced by roots of several tropical and sub-tropical plant species belonging to genera Lonchocartus and Derris. It is effective against caterpillars, beetles, aphids, flea beetles, weevils and thrips. Azardirachtin and Salannin: These are extracted from neem (Azardirachta indica), an Indian origin tree, and are effective against gypsy moths, leaf miners, white flies, caterpillars and mealy bugs. Sabadilla: It is extracted from seeds of Sabadilla lily and is effective against caterpillars, leafhoppers, thrips and bugs. Pyrethrins: It is derived from dry chrysanthemum like flowers and is effective against sucking pests. (ii) Microbial pesticides Use of microbial pesticides especially Bacillus thuringiensis (Bt.), a naturally occurring bacteria, is a disease organism to various insect-pests. Various formulations of Bt when sprayed on crop plants protect them from caterpillars of moths and butterflies. These pesticides suppress and do not eliminate insect populations, have narrow target range, critical application times and limited field persistence and shelf life. Microbial pesticides suppress pests by producing toxins specific to pests, causing a disease and preventing growth of other micro-organisms by competition. DipelTM, ThuricideTM and MVPTM are some of the commercial formulations of Bt. (iii) Mineral based pesticides Sulfur: It is a naturally occurring mineral and is used to control fungal diseases of plants and sucking pest. Commercial formulations of sulfur include Wettable Sulfur, ThioluxTM, Lime Sulfur etc. and are used to control powdery mildew, certain rusts, leaf blights and fruit rots; spider mites, aphids and thrips. Application of sulfur in hot and humid weather causes burning of foliage. Bordeaux mixture: It is primarily a fungicide and is effective against powdery mildew, leaf spots, blights, anthracnose, downy mildew and cankers.

Weed Management in Organic Vegetable Garden Following crop rotations, mechanical and manual inter-cultural operations and use of mulches controls weeds in Organic Vegetable Gardens. Intensity of weeds is significantly reduced when water is applied using the drip irrigation compared to surface irrigation. Crop rotations involving paddy are effective to control even the most obnoxious weeds like nut grass (Cyprus rotandus). Mulches are useful in most crops except the ones that are closely spaced. They control weeds by blocking the sunlight. In general plastics, both coloured and transparent, are used as soil mulches but some times plant debris is also used to cover the soil. The later also nourishes the soil after it is decomposed. Mechanical inter-culture is convenient in widely spaced crops like cucurbits. With little manipulation in plant spacing, mechanical inter-culture can be employed in crops like tomato, eggplant,, etc. Nutritive Value of Organically Grown Vegetables All plants get their food from soil. Continuous crop cultivation on same land depletes the soil of some nutrients. It is not possible to supplement soil with all plant nutrients through fertilization. Foods grown on depleted soils are deficient in some important nutrients. Such foods produce malnourished bodies prone to diseases. Injudicious use of nitrogen fertilizers increases nitrate level of ground and surface water. Vegetables grown under such situations especially lettuce and spinach suffer from higher concentration of nitrate content. The nutritive value and taste of organically grown foods is superior to that of conventionally grown ones. Nitrate level in vegetables grown with composted FYM is lower compared with mineral fertilizer. Organically grown vegetables exhibit not only decrease in the concentration of undesirable constituents but also increase in the level of desirable ones such as iron, calcium, magnesium, potassium, vitamin C and other trace elements. For example, organically grown leek has 3.74 times more vitamin C and carrot 2.3 times more

-carotene

content compared to conventionally grown crops. Tomatoes produced with organic manures possess better firmness and extended shelf life compared with the ones produced with application of the chemical fertilizers. Vegetables grown organically produce higher quantities of flavonoids. These are phenolic compounds that have potent antioxidant activity and are produced in plants in response to biotic and abiotic stresses. The need for these natural safeguards decreases when crops are protected from insect-pests and diseases by applying chemicals. Organically grown

vegetables are, therefore, more nutritious due to presence of higher amounts of antioxidants. Antioxidants neutralize free radicals present in the body system and minimize chances of occurrence of degenerative diseases like cancer, arthritis, memory loss, paralysis etc.. FLOATING VEGETABLE GARDEN Floating gardens are found in lakes of Kashmir valley especially the Dal Lake of Srinagar. Most of vegetables in spring and summer seasons are supplied in Kashmir from floating gardens. A floating base is prepared using the grass known as Typha that grows wild in Kashmir. Compost and other organic matter spread over this base act as a seed-bed for growing vegetables. Subsequent inter-culture operations and irrigation are accomplished with the help of boats. Besides vegetables, flowers are also successfully grown in this type of garden. This is a specialized type of farming and is, more or less, restricted to the Kashmir Valley. HYDROPONICS Hydroponics is generally defined as the science of growing plants without using soil by feeding them on solutions of water and mineral salts instead of relying upon traditional method of cultivating the earth. The term hydroponics is derived from the Greek words hudro-water and ponos-work means water working. Advantages of hydroponics over the traditional method of crop raising include better quality produce, quick growth, no soil or seedbed preparation, clean culture, consistent results and crop production even if the soil is sick or unfit due to salinity, poor structure and drainage problem. Hydroponic systems have some clear environmental benefits with the most significant being that they use 70-90% less water compared with many forms of conventional crop production. There should be no nutrient run off and hence reduced concerns about contamination of ground water, rivers, streams etc. The most widely used type of hydroponic system where a timer controls a nutrient solution to drip on to the base of each plant from a small drip line. Some include a recovery system where the excess nutrient solution that runs off is collected back to a reservoir for reuse. Hydroponics is popular in the Netherlands, Spain, Canada, Japan, UK, USA, Italy, New Zealand and Australia. Tomato, cucumber, lettuce and bell pepper etc. respond favourably to the hydroponic culture. The worldwide area of hydroponics production has increased four to five times in the last ten years or so.

Dr. William F. Gericke pioneered the technique of hydroponics. His soilless cultured tomatoes attained height of 25 feet. After that, he started raising a wide variety of other vegetables as well as flowers, root crops, fruits and cereals. The technology quickly spread to other parts of the USA as well as some parts of Europe. During the world wars, millions of tonnes of vegetables were produced for supply to the allied forces. The American armed forces still continue with their soilless gardens in the Far East. There are full-fledged hydroponics systems in Russian Space Station and American submarines. In countries like England, Germany, France, Netherlands, Switzerland, etc. flower firms prefer to employ the soilless culture for commercial purposes. Green house cultivation throughout the world is generally hydroponics where plants are grown with or without the artificial medium i.e. sand, gravel, vermiculite, rock-wool, peatmoss or sawdust, all meant for only mechanical support to the roots. In India, hydroponics center was established in 1946 at the Experiment Station near Darjeeling in West Bengal with the objective to evolve simple and inexpensive methods of soilless gardening.