Watercress: growth, care & benefits

Watercress is full of benefits for human health and often used to refine and decorate dishes. Learn everything you need to know about growing watercress here.

Watercress (Nasturtium), or yellowcress, is a species of aquatic herbs, often used to enrich certain dishes. It is closely related to garden cress (Lepidium sativum). While it remains rather unknown to many, its close relative garden cress enjoys a little more popularity. In this article, we will introduce you to watercress and hopefully persuade you to grow this aromatic and spicy herb at home.

Watercress: origin and characteristics

Despite the similarity of their names, watercress and garden cress are not as closely related as one might think. What they do have in common is that they both belong to the cruciferous family (Brassicaceae). You can easily recognize plants from this family by their four cruciform petals. But that is pretty much all that watercress and garden cress have in common other than their pungent and spicy taste.

Wild watercress was once widespread in Europe along streams and springs. It was commonly used as a tasty snack for in-between meals on long walks or hikes, especially among nature lovers. Today, this sensitive herb is not as common any more due to pollution. It can still be found in some areas all over the world, though.

The plant needs a lot of moisture and grows in shallow water of river and lake banks. Therefore, it is an aquatic plant. The green stems and fleshy leaves float in the water. You can spot watercress by its leaves protruding from the water. The plant retains its colour even in winter, which is why it is often the only fresh green vegetable on the plate, especially during the colder seasons.

The most popular types

The genus of watercress (Nasturtium) includes two species native to Europe. Watercress is commonly referred to as the true watercress (Nasturtium officinale). This species is large, and its stems can grow up to 90 centimetres long. One form of this species is red watercress (Nasturtium officinale f. rubrum) which, as the name suggests, can be identified by its bright red leaves. Smaller and more compact is onerow yellowcress (Nasturtium microphyllum). The infertile cross between the two species, brown watercress (Nasturtium x sterile), also occurs in nature. Its leaves have a bronze-like colouring during winter.

Growing watercress

Watercress was once cultivated on a large scale by farmers. Cultivation is somewhat cumbersome, as the plant requires constant fresh water. Nevertheless, watercress can also be grown in your own garden and even on your balcony.

When and where to plant watercress?

The most important thing for growing watercress at home is, of course, water. If you have a stream in your garden, lucky you, as that is the natural habitat of the plant right at your doorstep. Otherwise, you should try to get as close as possible to the natural habitat. Try digging a moat, for example, or grow your watercress in pots. The main thing is that the plant always has clear, cold and oxygen-rich water available to it.

If all of the above is not possible for you, the moisture-loving plant can even be grown in damp places in the garden.

Watercress prefers sunny to semi-shade conditions, but the plant does not enjoy full and direct sunlight much. Waters that the plant tends to occupy in nature are usually located in cool valleys and are sheltered from the sun.

When to plant watercress depends on the type of planting. You can sow the aromatic plant either around March or in early August. However, it is easier to plant cuttings, which you can do in summer.

Summary: Planting watercress

• Cultivation in and around water, in pot culture or in very humid places
• Sunny to semi-shady location, no blazing sun
• Sow in March or August
• Propagation via cuttings in summer

How to grow watercress: instructions

Before growing, look for a suitable location in your garden. Ideally, this would be an existing watercourse such as a stream or a pond with water circulation. If neither of these are available, you can of course create a water-filled ditch to grow your watercress – but that does require a lot of work. If you choose to go through with this, make sure to have a sufficient in- and outflow of water.

It is much easier to cultivate watercress in a pot. To do this, place the young plant in some type of planting device, preferably the shape of a bowl. Next, place the plant in a larger container, which you fill up with water until the soil in the bowl is about one centimetre under water. This way the watercress always grows in water. However, you must change the water every two days for it to remain fresh and cool and contain sufficient oxygen.

If you have a damp and shady location, you can even grow watercress without water. Just keep in mind that the plant should never be allowed to dry out completely.

Whether in a pot or at the edge of a watercourse, sowing watercress or growing it is done without much water, but with sufficient moisture. Only when the cuttings root, or when the seedlings have reached a sufficient size are they replanted or placed in water. However, the tips of the plant should still stick out of the water.

A mixture of garden soil, sand and some compost is suitable as a substrate. Depending on the location, however, this mixture needs to be adapted. In a pond, for example, you should not add any compost, as algae can easily get into it. In a garden bed or pot, however, humus-rich soil with a nice portion of compost is recommended. While sand ensures aeration in a pot with water, it is better to leave it out in the garden bed, otherwise the water will seep away too quickly.

Summary: How to plant watercress

• In a pond: garden or pond soil with some sand
• In the garden bed: garden soil with a portion of compost
• In pots: garden soil with about 30% sand and a portion of compost

Care measures

To grow your own watercress, the plant needs to be cared for well after planting. Luckily, watercress plant care is pretty easy. Once it has become an inhabitant of your pond or stream, all you really need to do is harvest it. As the plant is perennial and reproduces well under the right conditions, you do not need to worry about its survival.

When growing the plants in pots with water, looking after the herb requires a little more effort. It is important that you change the water every two days, otherwise the water will deplete the oxygen the roots urgently need. What is more, the water becomes cloudy and is enriched with nutrients after a few days. Watercress always needs clean and fresh water. Apart from this, the plant may need protection against the cold. Although watercress is basically adapted to temperatures in moderate climates, larger water bodies and streams will not freeze, but a small water body in a tub will. Therefore, use some garden fleece or other type of protecting material to cover the flower pot.

A big advantage of watercress is that it does not need to be fertilised.

Summary: How to care for watercress

• Always keep it moist
• Change water every two days in pot culture
• Use winter protection if growing watercress in a pot
• Do not fertilise

Harvesting watercress

Next, let’s focus on how to harvest watercress. The green leaves and shoots are harvested from September until around May, when the plant begins to flower. You can harvest throughout all of winter. Basically, watercress season is all year round. All you have to do is cut back individual shoots. However, do not be too radical and let the plant regain its vigour between cuts.

In general, it is advisable to only harvest from plants that live in running water. Without water circulation or when water is not exchanged regularly, bacteria may settle on the plant. Either way, it is essential to carefully wash the greens before eating them.

Apart from leaves and stems, flowers are also suitable for consumption as well as the seeds.

Pests and diseases

Like with almost every plant, there are certain diseases and pests watercress is prone to be affected by. One of them are snails, which are easy to spot as they feast on the parts of the plant that protrude from water. You can simply collect them off the plant. Aphids (Aphidoidea) can also be found from time to time. To get rid of aphids thoroughly rinse the plant in water. Wild ducks can be a problem in larger bodies of water. In that case, use nets to protect your crop.

Apart from pests, downy mildew fungus (Peronospora parasitica) may attack the watercress from time to time.

Yellow leaves on watercress

When watercress leaves turn yellow, it is a sign that something is wrong. First of all, the most important thing to check: has the plant always had enough water? The herb does not cope with lack of water and droughts.

Another potential cause are root problems. Lack of oxygen or pests in the root area can lead to the roots dying.

My watercress does not flower

Watercress blossoms every year around May. Freshly sown plants may still be too young to flower at this time. These plants will only start to flowering the following year.

Watercress: benefits and use in the kitchen

The mustard oil glycoside gluconasturtiin contained in watercress is what makes for the spicy pungency. Many representatives of the cruciferous plant family contain mustard oil glycosides. This is how cabbage (Brassica), for example, gets its typical cabbage smell. The taste of the mustard oil glycoside makes watercress an ideal refinement for soups and salads. It also works well with cheeses and spreads. Watercress flowers make beautiful decorations. When dried, the small seeds of the plant can be used for fresh flavour in home-baked bread.

What does the herb do for your body? As you can harvest fresh watercress in winter, it is an important source of vitamin A and C during the cold season. It also contains iron, iodine and folic acid. Watercress is therefore very healthy. And not only that, it is also used in herbal medicine. It is said to stimulate appetite and metabolism and is even used as an aphrodisiac. Caution is advised in advanced stages of pregnancy, it may cause pain if consumed in excessive quantities.

If growing watercress is too costly for you, our article on garden cress might be interesting to you. It is low-maintenance and equal in taste.