Watercress (Nasturtium officinale)1 is a leafy green member of the Brassicaceae family and a close cousin of mustard greens,2 cabbage3 and arugula.4 During the summer months, watercress produces tiny white flowers5 with edible seeds.6
The plant was widely available through the 19th century when watercress sandwiches were well loved with the working class in England.7 It fell out of vogue for nearly 100 years, but is once again regaining popularity, this time due to its high nutritional content.
There are three major types of cress: watercress, upland cress and garden cress. In many areas of the world, watercress has become more well loved, but garden cress remains the more sought-after in the United Kingdom.8 Watercress and garden cress are often confused with each other, but are in fact two different, yet related species.9
In the kitchen, watercress is highly versatile and may be used as a salad green, steamed or added to soups and stews. Watercress health benefits are related to the high number of phytochemicals contained in the plant.10
The flavor is like a mustard plant and wasabi. In its raw state there is a unique peppery flavor that diminishes as it’s cooked. The spicy essence of watercress adds a unique flavor to stews and soups. As the plant becomes more mature, it may turn slightly bitter, so it’s vital to harvest watercress at its peak.11
It’s vital to learn how to grow watercress in order to delight in the benefits. It prefers cool, flowing water.12
If your garden includes a water feature, that’s a fantastic place to start the plant.13 But, it can become invasive and spread rapidly along the surface of the water, choking out native plants.14 When grown in a water feature with other plants, it may take aggressive pruning to keep it under control.
Watercress is a perennial.15 When you find it growing in the wild, it will likely be partially submerged in running water. But, if you don’t have a water feature in your garden or a stream in your yard, you can still cultivate the plant in your yard or home under the right conditions.
Since the plants thrive in a wet environment, be sure to keep your garden, pot or indoor area moist at all times. Watercress grows best in just water, lending itself well to a hydroponic system in your home.16
It takes about seven to 14 days for watercress seeds to germinate.17 The seeds are tiny and may be sown outside about three weeks before the last frost. This is because the plant enjoys cool, but not frigid conditions.18 Take care not to let the soil dry during this time because the seeds have to stay moist in order to germinate.19
You can grow watercress outdoors either directly in the ground or in containers. While watercress can grow from seed, it’s easily transplanted. It also can be started from cuttings.20 Nearly any part of the plant may be cut, placed into a container of water and then transplanted once the roots have formed.
Watercress grows 6 to 24 inches tall.21 If you don’t have a water feature where you plot to grow watercress, you’ll want an area with rich, fertile soil in full sun. Watercress will tolerate some shade and grows best in hardiness zones 9A to 11.22 Although the plants can thrive in a wide range of pH,23 they prefer a pH between 6.5 and 7.5.24
To achieve the best moisture level when you plant in the ground, you may have to make a small bog on your property.25 This is easily accomplished by digging a hole approximately 2 feet across and 1 foot deep. Line the area with plastic pond liner, leaving a lip at the top so the plastic doesn’t slip under the soil.
Use a garden fork to punch a few holes on the sides for drainage and then fill it with one part each of garden soil, builder’s sand, compost and mushroom compost. Add this mixture to the pool liner, mixing it thoroughly and stopping approximately 2 inches from the top.26
Cover the remaining part with soil and then fill it with water. You may then plant seeds or cuttings or transplant watercress that has already rooted into the bog. Since watercress requires a fantastic deal of water, you may want to grow it in large containers to avoid having to build a bog.
Without a creek or water feature where the soil stays saturated,27 you may choose to build your own small water garden in a container. Be sure the container has large drainage holes at the base and add a layer of landscaper’s cloth at the bottom to keep the soil from escaping as you water.
Place small stones on the bottom layer for excellent drainage. Place a larger tray underneath your planting container and fill it with pebbles to allow water to flow freely into the growing container.28
Fill your container with a soilless mixture. This filling should contain vermiculite or perlite along with peat.29 Water it heavily and plant your seeds or transplant seedlings or cuttings into the container. Keep the drainage tray roughly half full of water and replace the drainage tray with fresh water every three to five days, making sure the tray never dries out.30
Watercress can also be grown successfully indoors under grow lights. If using standard fluorescent lamps, keep them between 2 and 4 inches from the tops of the plants. But, high output fluorescent lighting should be kept 1 foot above the plants.31
While growing indoors, use an oscillating fan near the plants approximately two hours each day to help simulate a natural habitat in which the watercress will grow shorter and sturdier.32 Your plants will have the same water requirements indoors as they do outside.
The flavor of your watercress is best before the plant flowers. In the hot summer months, when it has tiny white flowers, you’ll find the leaves have a bitter flavor. You may start harvesting about three weeks after the watercress has begun growing.33
By cutting the plants to 4 inches high you’ll encourage thick growth and have greens for your salad. Once you have cut them from the plant, wash them thoroughly.34
The best way to store watercress is in a glass jar filled with water with the stems submerged as you would cut flowers. As the plant’s water content is high, it perishes easily. With the stems submerged, you may be able to store watercress for up to five days.35
At the end of the season you might like to harvest the entire plant and store it with its roots, as this will keep it fresh for a longer period of time. If you are growing your plants indoors, you’ll have access to a harvest as needed. But, when your garden is outside and you’d like to delight in watercress after the first hard frost, consider pulling a few with the roots and keeping them in a glass of water.
Folklore holds that King Xerxes ordered his soldiers to eat watercress for health reasons.36 Hippocrates is believed to have built his first hospital near water around 400 BC in order to harvest a plentiful supply of watercress for his patients.37
During the Victorian era, the plant was transported over railways. In the 1930s, researchers concluded that watercress helps promote children’s growth. By the end of the 20th century, but, cultivation had shrunk and watercress was relegated to the status of a garnish rather than a staple.38
If the flavor seems familiar it’s because it’s a prime component of V8 vegetable juice.39 The plant offers generous amounts of vitamin C, vitamin A, calcium, iron and folic acid. But, more notably, 1 cup delivers 100% of the daily recommended amount of vitamin K.40 For more on the health benefits, see my previous article, “The Wonders of Watercress.”
This vibrant green plant is a tasty addition to soups and salads. If you aren’t harvesting from your backyard, watercress may be found in your local grocery store. Consider this recipe that combines the spice of watercress with the sweetness of pear.
Another salad recipe is my Watercress and Broccoli Salad, which combines a sweet and sour dressing with a pop of cranberry. Watercress can be a flavorful addition to your homemade soups. You may be interested in my Asian Chicken and Chilies Soup recipe. Since watercress complements leek soup, consider adding it to the Leek and celery root soup recipe at the end of this article.
Watercress, Spinach and Pear Salad
- 2 cups watercress, trimmed; use sprigs
- 2 cups spinach, rough chopped
- 1 1/2 pounds pears (1 large or 2 medium)
- Salt and pepper, to taste
- 1 carrot, shredded
- 1 tablespoon sesame seeds, toasted
- 1 tablespoon fresh ginger, roughly chopped
- 1/4 cup seasoned rice vinegar
- 1/4 cup smooth almond butter
- 1 1/2 tablespoons sugar (or raw honey)
- 2 tablespoons water or more if needed
- 1/2 teaspoon chili paste, or to taste
- 1/2 teaspoon salt
- 3 tablespoons toasted sesame oil
- Place watercress and spinach in a large bowl.
- Cut pears into thick matchstick-like slices.
- Toss gently with the watercress and spinach.
- Season with salt and pepper to taste.
- Place all dressing ingredients in a blender and blend until smooth.
- Drizzle dressing over salad and garnish with grated carrots and toasted sesame seeds.