Sow seeds any time of the year. Cress can be grown in trays of compost or on the surface of pads of cotton wool, flannel, kitchen towel etc. Place the growing medium in a small container or saucer and moisten well, then spread the seed thickly over the surface. Place in a polythene bag and leave in a warm place. For outdoor sowing, choose a partially shaded spot of ordinary reasonably moist garden soil. Sprinkle the seed liberally on the soil surface and cover with a mat or thick brown paper until the seeds germinate. Keep moist until you harvest
Keep the seeds dark until after germination and then move to a warm well lit spot ensuring that the medium stays moist. Cress is ready in around 10-14 days after sowing.