Heirloom, Non-GMO Yellowcress Lettuce, Xa Lach Xoong or CAI Be Xoong | Easy to Grow, Fresh Flavor for Culinary - bright and fresh taste with a peppery kick, these seeds are packed with care, ensuring optimal freshness and germination. Suitable for both beginners and expert gardeners. When to Plant Watercress can be grown from either seeds or cuttings, and grows best in cool weather. To grow watercress from seeds, you can follow these steps: Direct sow outdoors when soil temperatures are between 50 and 60 degrees F, or start seeds indoors 3-4 weeks before the last frost date. Surface sow the seeds, very lightly covering them with seed-starting mix or pushing them about ¼ inch deep. Keep the soil consistently moist until germination occurs (usually within 7-14 days). Thin the seedlings to 4 inches apart. Transplant to larger pots or the field with fertile, humus-rich, well-limed soil. Learn how to plant, care for, and harvest watercress, a water-loving herb with a peppery taste