Onion (Allium cepa) is an important root vegetable, serving as a staple ingredient in many Indian dishes. It is a member of the Allium family, which also includes garlic, leeks and chives. They are known for their pungent flavor and aroma, which are caused by sulfur-containing compounds. India is one of the largest producers of onions in the world, with the states of Maharashtra, Karnataka and Gujarat being major onion-growing regions. India produced about 32 million metric tons of onion in the year 2022. Total area under its cultivation in 2022 is 1.94 million hectares. The demand for onions in India is high, and the crop is an important source of income for many farmers in the country.   Soil Requirement Almost all soil types are suitable for onion cultivation. However, sandy loam to clay soil with good drainage, moisture holding capacity and rich in organic matter is considered ideal. Optimum soil pH for its growth is 6 – 7.5. Onion is sensitive to highly acidic, saline and alkali soils. Avoid waterlogging in the field.  Season and Time of planting States  Seasons  Sowing time  Transplanting time  Harvesting time  Maharashtra, Parts of Gujarat  Kharif  May – June  July – Mid Aug  Oct – Dec  Early rabi or late kharif  Aug – 1st week of Sept  Sept – Oct  Mid Jan – Feb end  Rabi  Oct – mid Nov  Dec – Jan 1st week  Apr – May  Tamil Nadu, Karnataka and Andhra Pradesh  Early kharif  Mar – Apr  Apr – May  Jul – Aug  Kharif  May – Jun  Jul – Aug  Oct – Nov  Rabi  Sept – Oct  Nov – Dec  Mar – Apr  Rajasthan, Haryana, Punjab, UP  Kharif  May end – Jun  Jul – Mid Aug  Nov – Dec  Rabi  Oct end – Nov  Mid Dec – Mid Jan  May – Jun  West Bengal, Orissa  Kharif  Jun – Jul  Aug – Sept  Nov – Dec  Late Kharif  Aug – Sept  Oct – Dec  Feb – Mar  Hilly regions  Rabi  Sept – Oct  Oct – Nov  Jun – July  Summer (long day type)  Nov – Dec  Feb – Mar  Aug – Oct    Varieties of onion States  Onion Varieties  Karnataka & Telangana   Nasik Red onion (N-53), Royal selection onion, JSC Nasik Red onion (N-53), Prema 178 onion  Andhra Pradesh   Nasik Red onion (N-53), JSC Nasik Red onion (N-53), Prema 178 onion, Gulmohar onion  Madhya Pradesh   Nasik Red onion (N-53), Gulmohar onion, Laxmi onion seeds diamond super, Royal Selection onion, Rise Agro Maha Onion Bhima Super seeds  Maharashtra   Nasik Red onion (N-53), Gulmohar onion, JSC Nasik Red onion (N-53), Royal selection onion, Laxmi onion seeds diamond super  Uttar Pradesh   Nasik Red onion (N-53), Royal selection onion, JSC Nasik Red onion (N-53), Prema 178 onion, Gulmohar onion    Different Methods of Growing Onions Onions can be grown in three different methods depending upon the purpose of their cultivation.  Seed sown in nursery and then transplanting the seedlings in mainfield  Raising small bulblets for green onion production  Broadcasting or Direct sowing  Nursery Management Onion seeds are generally sown in nursery beds.   Preparation of nursery bed: For 1 acre main field, 0.05 acre i.e., 200 m2 of nursery area is required. Apply 200 kg of FYM mixed with 2 litre of Trichoderma harzianum at the time of last ploughing helps in controlling damping off, root rot, collar rot and other soil borne diseases. Prepare raised beds of 1 – 1.2 m width, 10 – 15 cm height and of convenient length. Maintain 70 cm distance between the beds.   Seed rate: 3 – 4 kg seeds are required for 1 acre field.  Seed treatment: Before sowing, treat the seeds with Bavistin at 2 gm/lit of water for 1 kg seeds or in bio fungicide by mixing 8 – 10 gm of Trichoderma viride in 50 ml of water for 1 kg seed to prevent damping off and other diseases.  Sowing: Sow the seeds in line at 5 – 7.5 cm apart at 1 cm depth. After sowing, cover the seeds with fine soil, powdered FYM or vermicompost. Give light irrigation. Drip or sprinkler systems of irrigation can be adopted. Cover the beds with paddy straw or sugarcane leaves or grass to improve germination by maintaining required moisture and temperature. Drench the soil bed with Carbendazim 50% WP at 0.5 – 0.75 gm/lit water to prevent damping off. Add 0.5 kg/bed of 15:15:15 (NPK) after 10 days of sowing, if seedlings show nutrient deficiency symptoms. Mulched grass or straw can be removed after germination is completed.   Raising small bulblets for green onion production This method is used for production of green onions/bunching onion which have demand for salad in early winter. For this, take small onion bulblets of kharif onion varieties raised in previous season for planting. Prepare raised beds or flat beds depending upon soil type (Raised bed – heavy soil; Flat bed – sandy soil). 15 grams of seeds are sufficient for 1 m2 area of bed i.e., 3 kg seed is required for total nursery area. Sow them in mid Jan – Feb starting to get quality bulblets. Leave the plants in nursery bed up to April to May till their top fall. Harvest the tops and selected bulblets and store them by hanging method till July. These stored small bulbets can be used for transplanting in the kharif season for raising green onion.  Broadcasting/Direct sowing Seed rate: 8 – 10 kg/acre; Time of sowing: Sept – Oct  In case of big onion, sow the seeds in lines at 30 cm apart (30 cm within row and 30 cm between plants). Later, thinning can be done to give proper spacing for bulb development. In case of small onion, broadcast the seeds in small flat beds. Do hand hoeing after sowing the seeds to allow seeds to reach 2.5 – 3 cm depth. Give light irrigation. At 10 days interval, weeding can be done.  Land preparation for main field  Plough the field to a fine tilth and add 10 t of FYM at the time of last ploughing. Flat beds or broad bed furrows can be formed for transplanting the seedlings. Prepare flat beds of 1.5 – 2 m width and 4 – 6 m length. For broad bed furrows, prepare beds of 120 cm width and 15 cm height with 45 cm furrow spacing between two beds. Irrigate the beds before transplanting seedlings.   Transplanting of seedling from nursery  Seedlings raised from seed sown nursery will be ready for transplanting within 6 – 7 weeks of sowing for kharif and 8 – 9 weeks for rabi. Transplant the seedlings with a spacing of 15 cm between the rows and 10 cm between the plants.   Fertilizer Requirement for Onion Crop The general dose of fertilizer recommendation for onion is 60:24:24 kg/acre.  Nutrient  Fertilizer  Dosage  Time of application  Organic  FYM  10 t/acre  At the time of last ploughing  N  Urea  65 kg  Basal   65 kg  Top dressing (after 20 – 25 days after transplanting)  P  Single Super Phosphate (SSP)  150 kg  Basal  K  Muriate of Potash (MOP)  40 kg  Basal  Micronutrients  Anshul Vegetable Special    Spray: 2.5 gm/lit water  20 – 25 days after germination.  (Give atleast 3 sprays with an interval of 20 days)      Water Management  Onion is mainly grown as an irrigated crop. Frequency of irrigation depends upon the climatic conditions and soil type. Irrigate the field at the time of transplanting the seedling. Give another irrigation on 3rd day after transplanting. Then, depending upon the soil moisture irrigate at an interval of 10 – 15 days. Stop irrigating the field 10 days before harvest. Avoid over watering or less watering as it may affect onion growth and development. Drip or sprinkler irrigation systems can also be adopted.  Weed Management  It is important to keep the field free from weeds during the initial growth stages.  Apply Oxyfluorfens 23.5% E.C at 200 ml/acre followed by one hand weeding 45 days after transplanting for effective weed management.   Crop Rotation and Mixed cropping  Onion can be grown as an intercrop with sugarcane during the initial 5 months after planting sugarcane. They can be rotated with legumes, corn, brassica and solanaceous crops. Onions are heavy feeders and can quickly deplete the soil of nutrients. Rotating onions with legume crops can help to replenish the soil with nitrogen. Corn, on the other hand, is a non-host for onion pests and diseases, which can help to reduce the build-up of these problems in the soil. Similarly, rotating brassica and solanaceous crops with onions can help to maintain soil health and prevent the build-up of pests and diseases.  Plant Protection Practices  Pests of Onion crop  Pests  Symptoms  Control Measures  Onion Thrips  Thrips infested leaves will be curled and twisted.  Shows silvery patches on leaves.  Distorted leaves and wilting and drying up of plants.  Spray Neem 0.3% at 2.5 – 3 ml/lit water.  Spray Delegate Insecticide at 0.9 – 1 ml/lit of water.  Spray Curacron Insecticide at 2.5 ml/lit water.  Head borer  They feed on the flower stalk by cutting its pedicel.  Makes entry holes in the onion bulb, which can be seen as small, round holes near the top of the bulb.  Larvae leave behind small pellets of excrement (frass) near the entry holes.  Use 6 Tapas helic-o-lure per acre with funnel trap.  Spray 0.5 – 1 ml of Sun Bio Hanpv mixed in 1 lit of water.  Spray Ekalux Insecticide at 2ml/lit water.  Spray Cigna Insecticide at 1.5 – 2 ml/lit water.  Onion fly  Flies may lay eggs on older leaves and soil.  Maggots tunnel into the onion bulb and feed on the flesh, causing damage to the bulb.  Maggots feed on the roots of onion plants, causing stunted growth.  Infected plants become yellowish and later wilt.  Use 4 Barrix catch vegetable fly trap for 1 acre to control adult flies.  Spray Alika Insecticide at 0.5 gm/lit water.   Spray Keefun Insecticide at 2 ml/lit water.   Cutworms  Young larvae feed on the tender foliage causing them to wilt, yellow, or brown.  Later, as they grow up, they cut off young onion plants at the base of the stem leaving behind ragged edges or holes and causing them to wilt and die.  Spray Vedagna Nobor at 2.5 – 3 ml/lit water.  Spray Beauveria bassiana (Dr Bacto’s) at 1 – 1.5 gm/lit water.  Spray Plethora Insecticide at 2ml/lit water.  Eriophyid mite  They feed on the young leaves between the layers.  The leaves may turn yellow mottled at the edges.  The leaves curl up and may not open up completely  Spray neem oil extracts at 1 – 2 ml/lit water.   Spray Royal Clear Mite at 2 ml/lit water  Spray Sedna Insecticide at 1 – 1.5 ml/lit water.  Spray Oberon Insecticide at 0.3 ml/lit water.   Red Spider mite  Nymph and adults feed on the undersurface of the leaves causing stippling or white dots on leaves.  Presence of webbing on leaves.  Affected leaves may show yellow or bronze spots in severe cases.  Spray Terra Might at 3.5 – 7 ml/lit water.  Spray Meothrin Insecticide at 0.5 ml/lit water.  Spray Movento Energy Insecticide at 0.5 – 1 ml/lit of water.    Diseases in Onion crop  Diseases  Symptoms  Control Measures  Damping off  Wilting and collapse of the stems at or below the soil line.  Stems of infected seedlings may turn brown or black  Rotting of roots.  Infected seedlings may appear dried out or desiccated.  Spray Amruth Alcare Liquid at 2 – 3 ml/lit water.  Treat 1 kg of seeds with 10 grams of Trichoderma viride.  Drench the soil with Ridomil Gold at 1 – 1.5 gm/lit of water.    Basal rot  Soft, mushy rotting at the base of the onion plant, which can lead to the collapse of the plant.  Leaves appear yellowish and later dry up.  Presence of white mold growth on onion scales.  Treat 1 kg of seeds with 3 gm of Vitavax powder.  Dip the seedling before transplanting in Carbendazim at 2 gm/lit of water.   Drench the soil with Dhanustin Fungicide at 0.5 – 0.8 gm/lit of water.  Soil drenching with Blue Copper Fungicide at 1 – 2 gm/lit of water.  Downy mildew  Development of greyish mold on the undersides of the leaves, causing them to curl.  Leaves of infected plants may start to yellow and eventually turn brown and dry.  Spray Amruth Alcare Liquid at 2 – 3 ml/lit water.  Spray Downy Raze Bio fungicide at 2.5 ml/lit of water.  Spray Dithane M45 Fungicide at 2 – 2.5 gm/lit of water.  Spray Amistar top Fungicide at 1 ml/lit of water.  Stemphyllum Blight  Affected leaves have small yellow to orange streaks in the middle of the leaves.  Later, these water-soaked streaks enlarge and coalesce, forming irregular or spindle shaped spots with pinkish margin.   Apply 5 – 10 gm of Pseudomonas fluorescence & Bacillus subtilis per liter of water as spray.  Spray Indofil M-45 at 0.8 – 1 gm/lit of water.   Spray Blitox Fungicide at 1 – 2 gm/lit of water.  Bacterial brown rot  (Serious disease during storage)  Brown, water-soaked streaks/spots appear on the neck of the bulbs.  Infected tissues become soft and slimy, with a foul odor.  Ensure proper curing and drying of onion bulbs.  Spray Geolife Geomycin at 0.5 – 1 gm/lit of water.   Spray Dhanuka Kasu-B Fungicide at 2 – 2.5 ml/lit of water.  Smut  Black, powdery spores appear on the leaf base and leaf surface.  Presence of black lesions on base of the scales at the time of planting.  Downward bending of affected leaves.   Treat the seeds with vitavax powder at 3 gm/kg seed.   Dip the bulb in suspension of 20 ml of Trichoderma viride in 1 liter of water before sowing.   Spray or Soil Drench Dithane M45 at 2 – 2.5 gm/lit water.  White rot  Yellowing and dieback of leaf tips.  Presence of white, cottony fungal growth on the decaying scales and base of the bulb.  Small, spherical, black sclerotia are produced.   Complete rotting of bulb.  Follow crop rotation.  Use clean seeds for sowing.  Treat 1 kg of seeds with 2 – 3 gm of Roko Fungicide.   Spray Tebusul Fungicide at 2.5 gm/lit of water.    Purple blotch  Small, irregular purple spots on the leaves.  Later, these spots enlarge and become blotches.  The blotches may have a white center surrounded by a purple border.  Spray Trichoderma viride at the rate of 3 gm/lit water    Spray Custodia Fungicide or Spectrum Fungicide at 1.5 ml/lit of water.  Spray Cabrio Top Fungicide at 1.2 – 1.4 gm/lit of water.  Anthracnose  (Twister Disease)  The leaves will also get curled and twisted with water-soaked pale-yellow patches on the leaf blades.    Spray 0.5 gm/lit of Roko Fungicide.  Spray Dhanuka M45 at 3 – 4 gm/lit of water.  Neck rot  The neck of infected onions becomes soft and watery, which can lead to the onion falling over.  Infected necks can turn brown or black infected onions emit a foul smell,  Necks of infected onions can become spongy to the touch.    Ensure proper drying before storage.  Avoid injury to bulbs during post-harvest handling.  Spray Carbendazim 2 gm/lit of water before harvesting.  Onion yellow dwarf  Vector: Aphids  Yellow streaks on base of true leaves.  Leaves may turn yellow, starting from the tips and moving towards the base.  Affected leaves become crinkled and flattened.    Use virus free seedlings.  Spray Geolife No Virus at 3 – 5 ml/lit of water.  Spray Police insecticide at 0.2 – 0.6 gm/lit of water to control vector.   Irish Yellow Spot Virus  Vector: Thrips  Presence of dry, straw coloured, tan, spindle shaped lesions with yellow or tan borders on leaves.  These lesions may or may not have green centers.  Practice crop rotation every 3 years.  Removal of weeds.  Spray Terra Virokill at 3 ml/lit of water.  Control measures of thrips are given above can be followed.   (Note: Check the product’s label before application to know the right time of application.)  Harvesting  Time of harvesting depends on the purpose for which the crop was planted. For dry onions, harvesting can be done in 5 months while for green onions, harvesting can be done in 3 months after harvesting. For harvesting rabi onion, the indication is 50% of neck/top falling over. Harvesting is done by manually uprooting the bulbs. But for kharif seasons, since the top does not fall over, the sign of harvest is change in colour of leaves to slight yellow and red pigmentation on bulbs. During hot days when soil is hard, use hand hoe to pull out the bulbs. Spray the crop with Carbendazim 2 gm/lit of water which will help harvested onion protect from any kind fungal infections after harvest.  Curing  After harvesting, onions need to be cured to prolong the shelf life, for proper development of skin colour and remove field heat before storage. For curing, spread them out in the field without direct exposure to sun by covering the onion bulbs with foliage of other bulbs in small heap.  Allow the onions to dry for 3 –5 days, until the leaves and stems are completely dry and brittle. After complete drying, cut the leaves leaving about 2 – 2.5 cm tops above the bulb.   Storage  Once the onions are cured, they can be stored in a cool, dry location. It is important to store them in a well-ventilated area to prevent mold and rot. Onions can be stored for several months if they are properly cured and stored.   Yield  8 – 10 t/acre.