Heirloom Vegetable. While traditionally grown along stream banks or in other moist areas as an aquatic or semi-aquatic plant, watercress can also be successfully grown in containers set in a saucer of water (change the water regularly). Watercress has a creeping growth habit and develops broader leaves than extra curled cress. The dark green leaves and stems have a crisp, pungent flavour when young. Well suited to hydroponic gardening. Watercress becomes bitter when it starts to flower. Reliably hardy outdoors to Zone 6, possibly to Zone 5 as well.
How to Grow
In a mostly sunny to a lightly shaded area, scatter seeds on the surface right along the waterline of a stream with clean, slowly moving water. Some seed will fall on the soil and of course some will fall into very shallow water. Seed can also be started in a container filled with 5-7.5 cm (2-3″) of an open growing mix. Sow the seed on the surface and lightly cover with the growing medium to no more than 6 mm (1/4″) deep. Set the container in a tray/saucer containing water. Never let the growing medium dry out – do this by always ensuring the tray/saucer is filled with water. At the same time, remember to change the water in the tray/saucer regularly to prevent it from becoming stagnant. Harvest stems by cutting them off close to the soil line once they reach about 15-20 cm (6-8″) in length.