Steps Required to Cultivate Onion
Bulb onion is consumed on a daily basis in food dishes as spices when cooked or served as raw food, and is one of the commonly grown vegetable.
It is rich in Calcium, Iron, Potassium, Vitamin B6 & B9, Vitamin E and has medicinal properties. Onion cultivation is one of profitable agribusiness which you should venture into.
This article will take a look at the steps required for you to cultivate onion for optimal yields.
Optimal Ecological Requirements For Growing Onion
Onion requires an altitude of 1,900 m above sea level for it to give optimal results. It also requires a well-distributed rainfall of between 500 and 700 mm during the growing period and a dry spell is needed at maturity.
The optimum temperature for growth of onion is 15 – 30 °C. If the temperature exceeds 30°C, maturity in onion is hastened & small bulbs are produced, consequently lowering the onion yields.
When the temperature is low, growth is slowed or the plant may result to flowering. The cold weather is also associated with increased leaf diseases.
Onions cultivation requires fertile well-drained soil and the optimum pH range for growing onion is 6.0 to 6.8. Sandy to silty loams with fine tilth is required.
Steps Required to Grow Onion
For successful cultivation of onion, make sure you follow the following steps required for you to grow onions.
1. Site selection
The first step required for you to grow onions is to select a suitable site which matches the optimal ecological required we have discussed above.
Make sure the selected site has good soil fertility, which is well drained sandy to silt loam soil, with fine tilth.
If the onion cultivation will be under irrigation, make sure the selected site is close to the water source. The selected site should be free from diseases and insects.
2. Site preparation
Having chosen the best site to grow your onion, the second step is to prepare your site to make it ready for growing your onion. Site selection involves, clearing the site, ploughing and making ridges or seedbeds.
It also includes application of manure, which aim at improving soil fertility and structure, which encourages your onion to give high yields.
During site preparation, make sure the site is well prepared such that it is loose to a depth of at least 75cm and if heavy rain is expected in the early stages of growth, raised beds or ridges will reduce the effect of any waterlogging.
Where onion seed is to be direct-sown, a fine even seed bed is vital in order to produce an acceptable stand.
During site preparation, apply calcium super-phosphate at the rates recommended locally.
3. Planting
Onion can be down directly sown into the actual field or it can be sown in the nursery bed, and later transplanted to the actual field.
Whether you will sow your onion seed directly into the actual field or you will sow in nursery beds and later transplant, in which case make sure you achieve an onion plant population of 700 to 800,000 plants per hectare and this will give the highest proportion of medium-sized bulbs which are preferred by market demand. Make sure your onion seed is sown at a depth of 1 – 2cm.
Optimal sowing dates for onion seeds vary with locality, soil type and variety. Germination takes 7-10 days.
If you will not use direct sowing, you can sow your seeds on a nursery bed and later transplant as we have previously said.
Take note that your seedlings will need to be transplanted at 6 – 8 weeks after sowing or at 3-5 well formed leaves when the base is pencil thick.
The onion seedlings are transplanted in 2.5 to 3 cm deep trenches at a spacing of 30 cm between rows and 8 – 10 cm between plants (when using furrow irrigation).
5. Irrigation
Onions require light and frequent irrigation. The frequency of irrigation depends on soil type. Usually irrigate on a 4-7 days schedule is optimum.
Make sure the soil is not over irrigated or let be dried and cracked. Increase the water application as plants and roots increase in size.
6. Weeding
In your onion field, make sure any weed is removed instantly as weeds, are known to attract pest and diseases which may attack your onion. Use a hand hoe to remove the weeds or you can use herbicides to control the weeds.
If you have more hectares of land to be weeded, you can hire human labour to make the weeding easy and timely completion.
7. Fertilizer application
For optimal results, apply nitrogen and potassium fertilizer at 2 or 3 times on a 3 week schedule. It is highly recommended to apply a foliar application of micro-nutrients to onion seedlings when they are about 45 days old for increased yields.
In your onion field, top-dressing can be done in 2 splits with 1st top-dressing in 30 days after transplanting at 40 kg/acre of CAN. The 2nd top-dressing should be done in 45 days after transplanting at 80 kg/acre of CAN.
8. Pest and disease control
If you will not use direct seedlings, make sure the onion nursery is free from grasses and weeds and maintain this in the actual field after transplanting.
Take note that one or two applications of fungicides and insecticides are needed during the period of transplant. Extra care must be utilized when selecting and applying herbicides to onion.
9. Harvesting
Onion harvesting is done between 90 to 150 days after transplanting depending on the variety. Bulb Onions are ready for harvesting when their leaves collapse or when 75 % of the tops of the crop have dried and fallen over.
To harvest you lift the mature onion and left it to dry in windrows or heaps until cured.
In conclusion, this article has taken a look at 9 steps required to grow onions. Among others, the article has uncovered that, site selection, site preparation, planting and irrigation, are some of the required steps when cultivating onion.