By Umar Nsubuga
The onion remains an important source of nutritional value and income generation. They contain a lachrymatory agent, which is an antibiotic with fungicidal, bactericidal and nematocidal properties. Thus, it can be used as medicine.
“The most grown varieties are red and bombay creole,” says Gideon Zakke, an agronomist.
“Onions can be grown from three major sources, seeds, setts and bulbs. During soil preparations, rotten yard manure, or compost of about half a wheelbarrow per cubic metre should be added,” says Joseph Munerya, an onion farmer from Kapchorwa district.
Onions have black seeds mixed with an equal quantity of sand before they are broadcasted or planted. The mixture is released slowly along drills of about three to four centimetres deep and in 15-30cm apart.
Onions grow best in deep and well-drained sandy soils. The setts are small bulbs planted by pressing them firmly into drills and covered until only necks are visible.
The drills should be 30cm apart. Setts will start growing quickly once replanted and will mature sooner than seed-grown plants.
Onions may also be propagated from bulbs, which have been cut across the top to accelerate the growth of buds.
The buds, when old enough, can be removed and then planted as onion sets. Keep the bed well-watered.
Zakke explains that the soil must not be water-logged to a depth of 30cm.
“Water every 10-14 days for the first three months and thereafter weekly,” he says.
Munerya says after 60 days, the seedlings should be about 12cm high. Thin out small and stunted seedlings. Transplant the remainder in rows 30-45cm apart with 5-15cm between plants, depending on the ball size required.
Spread the roots carefully in the hole and press firmly around each plant with direct planting. After five weeks, the plants should be thinned until they are 5-10cm apart. The thinning can be eaten as green onions which are very good in salads.
Thrips, tiny insects which suck the leaves, leaving silver marks, attack onions. Caterpillars attack young onion plants and need to be quickly destroyed to save plants.
Onions mature after 90 days. The onions should be dried on a tray for three days while covering each bulb to avoid sunburn.
After drying the bulbs together in bundles by their leaves, hang them up in a cool dry place or shade.
Prematurely harvested onions have a very short shelf life. The more coloured the onion bulbs, the better the storage life and the higher the dry matter content.
