A dual-purpose salad onion especially recommended adding color to the salad bowl. No thinning required. Will also produce mild-flavored bulbs if thinned to 7.5cm (3″) between plants. 10 weeks of maturity. 40 days bunching, 90 days bulb. Flavor is not as pungent as one would expect for a red onion; its mildness is well-suited for raw/fresh use.
When To Sow: February-June Harvest: May-October, germination: 7-14 days Full Sun. Spring onions can be started as early as February indoors, or from March to June direct-seeded. Sow in the autumn for an early spring crop. They grow well in any well-drained soil with decent fertility.
Starting Indoors: Onion seed can be notoriously tricky to germinate and, as a result, many growers choose to start their onions inside in flats. Use light, well-draining compost or seed starter, sowing seeds at a depth of 1cm (½”). Cover lightly with soil and moisten. Onion seeds germinate best at a soil temperature of about 70F. Also, it’s best to use fresh seed, as the germination rate drops sharply with each year the seed has been stored. To aid in maintaining proper humidity, cover flats with a piece of plastic wrap until seeds have germinated. Once germinated, remove onions to a cooler growing space and make sure they have adequate light. Once all threat of frost has passed, harden off and plant outdoors 10cm (4″) apart for bulbing/onions. For spring onions, feel free to plant them much closer together. Water the plants thoroughly after planting.
Direct Seed: Spring onions are easier to direct see as no thinning is needed after sowing. Simply sow thinly in any well-drained, moderately fertile soil in a sunny location. Plant in drills 1.5cm (½”) deep, in rows 23cm (9”) apart in growing position. If you’d like your Northern Holland onions to bulb out, plant 5cm (2in) for smaller bulbs or 10cm (4”) for larger bulbs. Sow at 2 to 3-week intervals for a continuous supply.