Spring onions will grow in any good fertile soil provided it is well drained. Sow seeds from late winter to summer at 3 weekly intervals. For an early spring crop sow seeds in autumn and over winter. Sow thinly 6mm (0.25in) deep in drills 15cm (6in) apart.
No thinning is required. Harvesting can usually start 6-8 weeks after sowing.