The Sweet Spanish Yellow Utah onion is considered a long day type. Large bulbs sometimes weigh 0.45 kg (1 lb) or more. Skin is a straw brown and the flesh is white. A very popular onion for slicing and eating raw because of its mild sweet taste. It has fair storage characteristics and moderate Pink Root tolerance. It is well adapted to Western Canada. Plant very early in the spring in a sunny location as soon as the ground may be cultivated and enriched with organic material. Press soil firmly over seeds. Allow plant tops to fall and die before harvesting. Smaller bulb sets can be stored to replant next year
Onions can be grown from seeds, sets, or transplants. If starting from seeds, start them indoors 8-10 weeks before the last expected frost date in your area. Transplants can also be purchased from a nursery or garden center. Onions prefer a sunny location and well-drained soil that is rich in organic matter. Soil pH should be between 6.0 and 7.5. If planting sets or transplants, space them 10-15cm (4-6”) apart in rows spaced 30cm (12”) apart. If planting seeds, sow them 1cm (½”) deep and 2.5-5cm (1-2”) apart in rows spaced 30cm (12”) apart.
Keep the soil moist but not waterlogged during the growing season. Onions prefer consistent watering throughout the season. Fertilize with a nitrogen-rich fertilizer every 3-4 weeks during the growing season. Onions are ready for harvest when the leaves turn yellow and start to fall over. Carefully lift the onions out of the soil and lay them out in a dry, well-ventilated area to cure for 1-2 weeks before storing.