Avoid fertilizing with a high sulfur fertilizer since sulfur may make onions more pungent. Onions need moisture at the beginning but less when the onions are approaching full size.2
Plant in a location that enjoys full sun and remember to water moderately. Yellow Sweet Spanish is generally regarded as a very hardy plant, so this plant will typically do well in a variety of different extremes of cold temperature. Yellow Sweet Spanish needs a loamy, clay and sandy soil with a ph of 6.0 to 7.0 (weakly acidic soil to neutral soil).By our calculations, you should look at sowing Yellow Sweet Spanish about 28 days before your last frost date.
When the tops fall over and the tips turn brown onions are getting ready for harvest. The bulbs will be full size. Leaves should be left on and also the roots. Shake soil but do not wash. Let them cure for up to two weeks if weather is dry and not too hot. At this stage clip off roots and tops leaving about one inche of the stem and brush off any soil remaining.1
This variety tends to mature and be ready for harvest in early autumn.2 burpeehomegardens.com/VedgetableHerbGardening/PlantDetailss.aspx?plantid=5054#PlantingInstructions