Onion yields can be increased by growing them on fertile soils at minimum costs. Fertility can be improved by the application of organic or mineral fertilizer.
Onions can be grown on both sandy and loamy soils using fertilisers like aged manure or compost as these provide plant food. Organic fertilizer is mixed with soil at least 10 –20 cm deep in the ground.
Soil fertility
Apply just enough water, because too much water drains down nutrients. Alternatively increase water holding capacity by adding organic matter before transplanting for proper plant growth. Spread organic fertilizers mixed with top soil since onions have shallow roots.
Carefully apply inorganic fertilizers such as Nitrogen, phosphorus and potassium 2 weeks after transplanting, Nitrogen helps in quick leaf formation, Phosphorus for a quick root formation and Potassium for increased disease resistance. Potassium should be done during weeding and when plant show deficiency signs.
Constantly apply chemical fertilisers in smaller amounts by making shallow slits in between lines for plants to equally benefit. Avoid using urea 2 months before harvest since too much nitrogen makes bulbs softer. Apply potassium or wood ash to strengthen onion skin and lastly apply manure or compost to make soil softer for water infiltration and proper plant growth.
