Very quick growing salad onions, sow Spring Onion White Lisbon in succession for a continuous crop all spring, summer and autumn.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 (¼in) deep in drills 15cm (6in) apart.No thinning is required. Harvesting can usually start 6-8 weeks after sowing.