Cress Planting Guide About Cress This leafy annual vegetable is a zesty and spicy, fast-growing, nutritious accompaniment for use in all sorts of foods from salads to sandwiches and soups. When to Plant Plant seeds in early spring before the last frost. Cress grows quickly, and can be harvested in 15-20 days. Therefore, you can continue to sow cress seeds up until temperatures exceed 75 degrees F during the day, and then again in the later summer early fall when temperatures drop. Start seeds indoors 2-4 weeks before last frost and transplant to garden after danger of frost. Where to Plant Cress becomes very bitter in hot weather, so be sure to choose a cooler, shady area. Grow garden cress and curly cress in moist but well-drained sandy loam. Grow watercress in a container of compost-rich, sandy soil submerged in running water. Cress prefers a soil pH of 6.0-6.8. How to Plant Sow seeds 1/4" deep, thickly in wide rows with each row spaced approximately 18-24" apart. Sow successive crops every 10-14 days. Grow watercress in submerged containers. Caring for Cress Water generously to ensure roots do not dry out. You can spray seedlings daily to keep moist.Thin the cress once seedlings are 1-2" tall so that they are 6" apart from each other. Cress tastes best during its early seed/leaf stage, so cut or pinch tips of cress once it grows to about 3-4" tall. If you cut the plant back to 1/4", it will quickly regrow. Snip the stalks off at the base, and store in your refrigerator. Generally, it will last up to 1 week,.