True Watercress Seeds

Start Watercress seeds indoors 4–6 weeks before the last frost, or sow directly outdoors in early spring. Press seeds just 1/8 inch deep — they need close contact with the surface to germinate properly. Keep the soil wet the whole time; the plant cannot survive even short dry periods. At 60–70°F, most Watercress seeds sprout within 1–2 weeks. Once seedlings hit about an inch tall, thin to 8–10 inches apart.

The Watercress plant grows well in full sun, however,  in zones with hot summers partial shade slows the process of bolting. Soil should be consistently wet, not just moist, so skip sandy or fast-draining mixes. The most reliable method at home is to set pots with holes into a shallow tray of water and change it once a week. For garden beds, a low-lying spot that holds moisture or a place near a water source gives the best results. Rich, loamy soil with organic matter added gives you the best plants. 

Pinch out flower stems before they fully open to make the plant more productive. Regularly cut outer stems and leaves to keep the plant bushy. For sprouts, rinse at least twice a day and refrigerate once ready; they go off fast, so plan to use them within two or three days. In zones 7 and warmer, Watercress often overwinters, but in colder areas, treat it as an annual and start fresh Watercress seeds the following spring.