We have some watercress growing in terracotta pots about the garden, although it grows more naturally near and in running water. Watercress can be propogated from cuttings or seed. A bright (but not direct sun) well drained site, with some shade suits best and they need to be kept moist, which is why pots work well, mostly.
Autumn – Watercress is a cool season crop so harvest now and through early spring. Apply a foliar fertiliser that’s nigh in nitrogen – worm juice will be perfect for this. Dilute at least 10 to 1. Filling up the saucer of the pot with water will help keep the soil and plants moist. Take cuttings.
Winter – Consider repotting and adding compost to the soil.
Spring – Early spring will be a good harvest time until it gets too warm. Foliar fertiliser every fortnight or so and topping up the pots with compost will aide growth. Keep the saucer topped up with water. Plant cuttings or seed.
Summer – Mulch. Keep moist.
Generally – Watercress is highly nutritious and should be harvested lightly during the first season and then annually towards autumn. Cut regularly and remove any flowerheads to prolong the harvest and keep leaf growth progressing. Harvest older leavse near the stem tips for best flavour.
Eating – Watercress has medicinal properties (digestive, rheumatic, diuretc, blood sugar) and traditionally was taken as a spring tonic. Sandwiches are also traditional. Or a sauce for fish. Soup.