Conditions for Onion Farming
Onions perform well in well drained, fertile, sandy loam, non-compacted soils. The ideal pH is 5.8 to 6.8. Onion farming is a worthy venture since it’s possible to grow onions throughout the year via irrigation. Soil test with accredited laboratories is advised.
The ideal temperatures onions need to grow are between 13 – 35 degrees centigrade. This means that onions can grow in most parts of Kenya. However, to maximize production in areas such as Ukambani and some parts in the Coastal area, one needs to invest in a greenhouse and drip irrigation. This is because greenhouses will optimize the temperatures since these areas are hot and irrigation will provide the much needed water. Onions are a cool season crop. Most areas in Ukambani and the Coastal region are extremely dry.
In terms of requirements, apart from land that is an obvious fact, other requirements are DAP Fertilizer and seedlings. 1 kg of seedlings can be used in 1 acre while 20 grams of DAP Fertilizer is applied per square meter.
You should note that there are different seed varieties and they perform differently under different conditions. Common hybrid varieties available in Kenya include Red Creole, Red Pinnoy, Jambar 1 and Red Bombay.
Challenges facing Onion Farming in Kenya
Rains or Excess Watering: Too much rains or excess watering can water log the crop. If the rain in your area is too much, focus on growing the crop during the short rains. You can also raise the beds to ensure the water flows out of the field. Avoid excessive watering of your onions. The best type of irrigation on onions is drip irrigation. Overhead irrigation should be avoided as it causes fungal diseases.
Diseases: Common diseases that affect onions include Downy Mildew, Bacterial Soft Rots, Pink/White Root, Botrytis, and Rusts. Use herbicides to get rid of the diseases.
Pests: Common pests that attack onions include maggots, thrips, nematodes and the leaf miner. Use pesticides from accredited brands to get rid of the pests.
Weeds: Weeds can also destroy your crop and should be removed occasionally either physically or through the use of herbicides. In one season, there should be at least 2 – 3 weeding sessions.
The best time to do the harvesting is during the dry season. Keep a calendar and record the essential dates to ensure you harvest at the right time. Bulb onions are ready for harvesting once they form a shiny membranous cover around the bulbs or when the foliage withers. Spring onions are ready for harvesting when they are 15 centimeters tall and 1.5 centimeters thick.
Harvesting is done by pulling the bulbs and then chopping off the leaves. You then dry the bulbs in the sun before storing the produce.