Climate and Soil
Onion can be grown under wide range of climatic conditions, but it grows best under mild climate without extreme heat or cold, or excessive rainfall. Very low temperature at early stage results in bolting and sudden rise in temperature favor early maturity and small sized bulbs. The soil for onion cultivation should be rich in organic matter, free from diseases, weeds and should be well drained.Alkaline and low lying soils are not suitable for onion cultivation.
Agri Found Dark Red (AFDR) : The bulbs are medium large,deep dark red with an average yield potential of 120 q/acre. It is suitable for sowing in kharif season.
Sowing Time : The best time for sowing kharif onion nursery is middle of June, whereas to produce bulb sets it is middle March.
Nursery Raising : Nursery beds should be raised 20 cm above the ground level and 1 to 1.5 metre wide area of the nursery beds depends upon the number of seedlings required. Keep nursery bed and field area ratio of 1:20. Nursery soil should be well prepared and mixed with well rotton 125 kg farmyard manure per marla (25 sq.m.).The plot should be leveled and the nursery beds should be prepared accordingly. Continuously sowing of nursery on the same site should be avoided. Treat the seed before sowing with 3g of Thiram/Captan per kg of seed. Sow seed 1 to 2 cm. deep in lines with 5 cm.spacing. The seed should be sown uniformly in these lines and covered with a thin layer of well rotten farmyard manure. The seed should be sown in the proper moisture condition. First irrigation should be given just after sowing with the help of sprinkler. The nursery beds should be irrigated twice a day, i.e. in the morning and in the evening. The nursery bed should be protected from high temperature by covering it during day time. A shade straw or any other crop material should be placed at 1.5 m. height over nursery beds of 1.5 meter width preferably in North-South direction. Remove this structure after one month when the seedling shave established.
Bulb Set Technique :
To grow kharif onion crop successfully and avoid failure of seedling during June, planting with bulb sets is economical. To raise bulb sets, sow 5 kg. seed in beds of 8 marla200 sq.m.) in middle of March. Irrigate the seedlings twice a week.Medium sized bulb sets of 1.5-2.5 cm diameter give highest marketable yield. In the last week of June, uproot the bulb sets and store in a well ventilated dry room in baskets. Plant these bulb sets in the field in second fortnight of August. Bulb crop would be ready for harvesting by the end of November.
Manures and Fertilizers
Add 20 tonnes of farmyard manure with 40 kg of N (90 kg ofUrea) , 20 kg of P2O5 (125 kg of Single Superphosphate) and 20 kg ofK2O (35 kg of Muriate of Potash) per acre. Apply whole farmyard manure, P2O5 and K2O and half N before transplanting and remaining dose of N after 4-6 weeks of transplanting.
Transplanting : The nursery is ready for transplanting after 6 to 8 weeks of sowing. The seedlings should be transplanted in the first week of August. Planting at 15 cm between rows and 7.5 cm between plants in the rows is most conducive for high yield. The bed planting of sets improves the bulb size of kharif onion. Plant three rows oneach bed of 60 cm size. This practice is highly suitable under conditions where drainage is a problem. The transplanting should always be done in the evening. Irrigation should be given immediately after transplanting and subsequent irrigation should be given a sand when required.
Weed Control : Weed control is same as in rabi onion.
The crop is ready for harvesting in December. There is no seriousproblem of pests or diseases in this crop.
PRO-6 (2003) : The plants are medium tall, leaves are green,bulbs are deep red, medium to large, round with thin tight neck. It structure of takes 120 days from the transplanting to harvesting. It has good keeping quality and less bolting. The average yield is 175 q/acre.
Punjab White (1997) : The bulbs are medium large, round white with tight neck. It has high TSS (15%) and is suitable for dehydration.Its average yield is 135 q/acre.
Punjab Naroya (1995) : Its plants are medium tall, green and bulbs are red, medium to large, round with close neck. It takes 145 days from transplanting to harvesting and average yield is 150 q/acre. It is tolerant to purple blotch disease both in seed and bulb crop production and is also tolerant to the attack of thrips and Heliothis.
Sowing and Transplanting Time : Sow nursery from mid October to mid-November and transplant from the middle of December to middle of January. Large (10 to 15 cm) and healthy seedlings are better to get higher yields.
Seed Rate and Nursery Raising : Sow 4 to 5 kg seed to raise seedlings for transplanting in an acre. Prepare 15 to 20 cm. high beds in 8 marlas (200 sq.m). Mix 125 kg well rotten farmyard manure per marla and irrigate at least 10 days before sowing to allow complete germination of weeds. Sow seed thinly at one to two centimeter depth in 5 cm. apart lines. Transplant the seedlings in a wattar field soon after uprooting from the nursery beds.
Spacing : Close planting at 15 cm between rows and 7.5 cm between plants is most conducive for high yields.
Manures and Fertilizers
Add 20 tonnes of farmyard manure, together with 40 kg of N (90kg of Urea), 20 kg of P2O5 (125 kg of Superphosphate) and 20 kg ofK2O (35 kg of Muriate of Potash) per acre. Apply whole farmyard manure, P2O5 and K2O and half of N before transplanting and remaining dose of N after 4-6 weeks of transplanting.
Weed Control : Weeds are controlled by spraying Stomp 30EC (pendimethalin) @ one liter/acre or Stomp 30 EC @ 750 ml/acre followed by one hoeing. The herbicide should be applied within aweek after transplanting or after first irrigation. Alternatively, apply Goal 23.5 EC (oxyfluorfen) 380 ml/acre as early post-emergence(within 7 days after planting) using 200 liter of water followed by one hand weeding at 90-100 days after planting of onion nursery, for effective weed control.
1. Furrow Irrigation : Irrigate immediately after transplanting for proper establishment of seedlings. Depending upon the soil and weather conditions irrigate the crop at 7-10 day intervals. Stop watering at least a fortnight before harvesting to prolong storage life of bulbs.The total number of irrigation would be 10-15.
2. Drip Irrigation : Drip irrigation in onion results not only increase in yield but also save 43.88% of water as compared to conventional method of irrigation. While irrigating with drip irrigation,transplant six rows of onion at at 13 cm row to row distance and 7.5 cm plant to plant on 100 cm wide bed. Provide 40 cm space between the two beds. The onion crop should be irrigated with two lateral pipes per bed having drippers spaced at 30 cm and discharge of 2.2 liters per hour as per the following schedule. Under this system irrigation should be applied at an interval of two days. The onion crop should be irrigated should be applied at an interval of two days. The onion crop should be irrigated with a lateral pipe having drippers spaced at 30 cm and discharge of 2.2 liters per hour as per the following schedule :
If discharge rate is less than 2.2 liters per hour, time of irrigation may be adjusted proportionally by the formula.= 2.0 x Time of irrigation Discharge of dripper Fertigation saves 20% fertilizer. Apply 32 kg Urea, 13.12 kg MonoAmmonium Phosphate and 13.44 kg Muriate of Potash (white) per acre during first month of the translated crop in seven equal doses with every second irrigation (four days interval). The remaining amount of fertilizer 127 kg of Urea, 52.5 kg of Mono Ammonium Phosphateand 54.06 kg of Muriate of Potash (white) per acre should be appliedin equal doses during the rest of crop season in 20 equal doses with every second irrigation.
Harvesting and Storage
Harvest onion when tops dry up and fall. After harvesting cure the bulbs under shade and then cut the leaves 1-2 cm. above the bulb. Store in a well ventilated and dry place. Turn the bulbs once in a fortnight during storage and sort out and discard injured ones.
1. Bulb to Seed method
Onion seed is raised from the bulbs produced during the previous year. 8-10 quintals of graded mother seed bulbs are required for an acre. The bulbs are planted at 60 cm x 45 cm in first fortnight of November. The isolation distance between different varieties of onion should be 1000 meter. Extra early and late bolster should be removed.Depending upon size and variety of onion each bulb produces 5-12 flowering stalks. A minimum of three field inspections should be conducted to produce true to type seed. The first inspection before flowering, second at flowering and fruiting and third before harvesting of the seed crop. The off type and diseased plants should be rouged off. All the flowering stalks do not mature at one time. The primary head generally matures first, followed by secondary and tertiary umbels. Therefore, when the seed turn black, harvesting is done in at least 3 rounds.
2. Seed to Seed Method
Seed to seed method can be followed for commercial seed production in onion. It this method, seeds should be sown in nursery beds during last week of Aug. to first week of Sept. and seedlings should be transplanted in last week of Oct. to first week of Nov. at a spacing of 15 cm between rows and 10 cm plants. It will save one year time of bulb production and cost involved in storage of onion bulb.