For a jumbo onion, Yellow Sweet Spanish offers a mild flavor. Each bulb grows into a 4-inch sized fruit with mild onion flavor for eating raw or cooking.. Although it can take about 100 days for Yellow Sweet Spanish Onion to reach its full 4-inch size, you can harvest anytime after 2 weeks, even enjoying the green stalks above the bulb as a green onion.
Once the soil is drier and beginning to warm up, start sowing directly.
Sow onion seeds from late winter until mid-spring 1.3cm (½in) deep in rows 20cm (8in) apart. Thin out first to 5cm (2in) and later to 10cm (4in). Closer planting will result in more bulbs and a heavier crop, but smaller bulbs.
Sow shallots a little bit later from early- to mid-spring. Unlike shallot sets, seed-grown plants will only produce a single bulb. Thin out as required to 2.5-7.5cm (1-3in) apart.