Sow seeds in early spring and/or autumn very thinly in ordinary garden soil in drills 3cm (1in) deep in rows 30cm (12in) apart.
As the seedlings grow, gradually thin out to 23cm (9in) apart.
The thinnings can be trimmed off their roots and cooked. Water freely through the season and harvest by picking a few leaves, snapping them off close to the ground, from several plants rather than completely stripping one. If there are more leaves ready than you can use it is still best to pick them to encourage a steady supply of young green leaves.