In continuation of our article “Growing onions, the universal vegetable (I)” https://agronigeria.com.ng/growing-onions-the-universal-vegetable-i/ published yesterday Wednesday, July 17th 2018, we bring to you other things you need to know if you want to grow onions. These other requirements are as follows:
First irrigation is essential at the time of transplanting of seedlings or dibbling or cloves on the ground & a light irrigation is on the 3rd day of transplantation for better germination.
Then after, subsequent irrigation should be done at once a week or at an interval of 10 days on the basis of soil type and climate conditions because of the shallow root system in the onions.
APPLICATION OF MANURE & FERTILIZERS
Apply about 20 tonnes of farmyard manure as the basal dose at the time of land preparation along with 2 kg of Azospirillum and 2 kg of Phosphobacteria per hectare land.
Also, apply 50 kg of Nitrogen, 50 kg Zinc sulfate, 75 kg of Potassium and 150 kg of Phosphorous per hectare at the last plowing. Also, add about 50 kg of Nitrogen to the topmost soil after one month of transplanting seedlings.
Weeding is most important in the early growth phase. However, weeding is generally done 2 to 3 times within the onion planting season.
Onions do not compete well with weeds and yield can be severely impacted by excessive weed growth. Successful onion production requires good weed control. Irrigate the beds prior to transplanting to stimulate the germination of weed seeds.
Following planting, the field should be monitored regularly and weeds should be removed manually at the early growth stages before they start competing with the onion crop. Remove all weeds prior to transplanting.
PESTS AND DISEASES
Birds are known to lift onion sets by pecking at the skins. To avoid this, remove loose skin at the top of the set before planting.
Onions can be prone to a few different diseases:
Onion white rot
This occurs when the leaves wilt and yellow, or the plant becomes loose in the soil. Throw away any infected bulbs and do not plant onions, leeks or garlic on this land again for eight years.
This occurs on both onion and garlic, but usually is only a concern on onion. The pathogen, which survives in the soil, is splashed onto leaves and into the neck of the onion during rain or overhead irrigation.
The bacteria gain entrance through wounds and water soaked tissue. Once in a leaf, bacteria continue to grow down the blade into the bulb. Warm weather favors disease development; optimum temperatures for disease development are more than 30°C.
Other onions diseases include, Bulb rot, Downy mildew and Leek rust.
HARVESTING AND STORAGE
Bulbs harvesting should be done manually by hand pulling bulbs from the soil. Irrigation should be stopped before two weeks of harvesting bulbs.
Onion bulbs along with the tops should be kept on the field for about 3 to 4 days and curing for about 4 days in essential to eliminate the excess moisture of the bulbs from the outmost skin and neck to minimize the shrinkage & color development in the storage.
But, usually, onion bulbs are harvested when the neck fall reaches to 50 %age of the total crop since harvesting at full maturity is beneficial in higher production.
Onion tops will flop over when they are ready, and they will begin to turn yellow. At this point, leave them in the ground for several weeks. Then use a garden fork to harvest onions carefully.
For storage, lay onions in the sun to cure for two to three weeks. If the weather is wet, cure onions in a shed or other enclosed area with good air circulation. After harvesting, onions can be stored for about 6 months.