Purchase the watercress seeds. You can also treat watercress seed as a windowsill microgreen, surface sowing in small seed trays pre-saturated with water. Choose pots that will fit inside the larger container, and fill them with potting soil mixed with some lime. You can also start growing from mature watercress purchased at a supermarket or farmer’s market. Seeds can be ordered online or from gardening supply stores and nurseries. They are great for plants like watercress since they let in plenty of water without letting the potting medium out. Cut the ends, then soak the base of the stalks in water for a few days to encourage root growth and procee… Once growth is underway, keep the trays on saucers of water and harvest watercress microgreens when plants are 5cm (2") high or so. Add extra stones to the bottom to make sure the soil won’t wash away through the drainage holes in the bottom. The starting size of the pot doesn’t matter too much, but make sure it’s big enough for the number of seeds you intend on growing. Aquatic pots are fabric pots that have lots of small holes in them. Top tip: If you have a surplus of fresh leaves through summer, dont let them go to waste. Now fill the larger container with water, and set the ones with soil inside. Popular varieties of watercress include English Watercress and Broad Leaf Cress. Select an aquatic gardening pot to grow the seeds in.