To sow Onion Stuttgart Giant seeds, follow these steps. Begin by selecting the optimal time for sowing, ideally in early spring, between mid-March and mid-April. Prior to planting, prepare the soil by eliminating any weeds and incorporating organic matter to enhance its structure. Opt for well-drained, light soil, as onions thrive in such conditions.

Once the soil is prepared, create drills or shallow furrows spaced approximately 30cm apart using a hoe or rake. Scatter the onion seeds thinly along the drills, covering them with a light layer of soil. Adequately water the area and maintain moisture until seedlings emerge. To ensure successful germination, maintain a soil temperature of around 15-20°C (59-68°F). Avoid exposing the seeds to excessively low temperatures, as this may hinder germination or lead to weak seedlings.

As the onion seedlings reach a suitable size, thin them to a spacing of about 10cm (4in) for proper growth. Keep the area free of weeds and ensure regular watering. Onion Stuttgart Giant is a long-day variety, requiring at least 14 hours of daylight to form bulbs. Harvest the onions from late summer to early autumn, typically around August to September, when the tops turn yellow and fall over.

After harvesting, allow the onions to dry for a few days in a warm, dry location. Remove loose soil, trim the roots and tops, and store the onions in a cool, dry place, ensuring they last for several months.