Watercress is a swamp or aquatic plant that is valued by many hobby gardeners. As a hardy perennial, it is preferably planted in the garden pond or stream. The evergreen, herbaceous plant is also very popular as a healthy vegetable, rich in vitamin C and a tasty addition to salads and soups. The Nasturtium officinale, as its scientific name is, can be cultivated in a wide variety of ways; The main thing is that it is in a humid environment. Anyone who gets a little familiar with her needs in terms of cultivation and care can enjoy her dainty, white flowers as early as May.
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Cultivation in the pond and in the garden bed
The watercress plants you have grown yourself or bought ready-made cut a fine figure as a pond plant or in a stream. Since it is a fast-growing plant species, it is advisable to plant it in trellis-like planters. That way you have better control over them. In this water basket, the watercress is buried at the edge of the pond, where it then spreads on the ground and towards the water. Alternatively, it is placed in a water depth of no more than 15 cm. So that the substrate is not washed out of the plant basket with this variant, a weed fleece is put in first. This is followed by the earth, on which some pebbles are distributed.
Hobby gardeners who grow watercress for use in the kitchen place the young plants in a bed that is specially tailored to their needs. For this purpose, a trench 50 cm deep and 2 m wide is dug. It should have a water inlet and outlet and have a slight slope so that the watercress is in a slowly flowing, fresh water that reaches to the tips of the shoots. The planting distance is about 15 cm. The potting soil should be slightly sandy with a proportion of garden compost, with a pH value between 5 and 7. Only the 5 cm to 7 cm long shoot tips are then harvested, so that fresh watercress can grow back quickly.
If this method is too time-consuming, place the young plants in a waterproof planter in which the water is about 1 cm above the ground. The water should be completely changed at least once a week. Then the watercress feels at home here and offers a rich harvest, even throughout the winter.
Instead of planting ready-made watercress plants from the garden center, you can grow them yourself from seeds between February and April. For this purpose, a finely crumbly substrate is filled into a watertight cultivation vessel. Ideally, the substrate consists of sifted, well-rotted compost and sand. Resourceful hobby gardeners lay out this planter with crushed clay shards beforehand, because these store the irrigation water and thus support the moisture content of the substrate.
Put the seeds in the substrate but don’t cover them with it because watercress needs light to germinate. If the container does not have a lid, cover it with foil or damp paper towels. If the substrate is kept permanently moist, germination will begin after 7 to 20 days at a temperature of 20° Celsius.When the seedlings have reached a size of about 5 cm, prick them out. The weaker seedlings are sorted out so that the others have enough space to form sufficiently strong roots. The young plants develop best if they are kept in 1 cm of water from then until they can move to the garden in May. The experts advise against sowing the seeds directly at the edge of the pond or in the garden bed, because the seeds of the watercress are a favorite food for numerous birds.
Alternative cultivation without running water
Home gardeners who want to grow watercress for domestic use but do not have the means to provide the necessary supply and drainage of fresh water should consider the following alternative option:
A location in the vegetable garden is chosen that is sunny to partially shaded. A hole about 30 cm deep is dug in an area 2 m wide and 2 m long. The excavated earth is piled up all around to form a small wall. As a rule, this bed size is sufficient to provide an average-sized household with fresh watercress all year round.
The bottom of this bed is paved with bricks without the use of lime, mortar or cement. This soil will ensure that no standing water can form in the bed over a longer period of time because it will slowly seep away. On top of that comes a 2 cm to 3 cm thick layer of fine sand, which is followed by an equally thick layer of finely crumbly garden soil. The end is a 3 cm to 4 cm thick layer of good, sieved compost. The edge of this bed is fixed with wooden boards or with bricks. After leveling the soil, plant the young watercress plants in rows, 15 cm to 20 cm apart and water them with plenty of fresh water.
When the young watercress plants have reached a height of 5 cm to 7 cm, another thin layer of compost is added. From then on, fresh water is poured twice a day, which eliminates the need for inflow and outflow. A wooden walkway is simply laid over this bed for the harvest. Here the hobby gardener can kneel over the watercress to cut off the shoots. If a precise sequence is followed when harvesting, after cutting the watercress from the last row, you can continue in the first row again, because the shoots have already grown back there.
The quality of the water plays an important role in the care of marsh and aquatic plants. Watercress can only thrive in clean water, a factor that is crucial not only when growing as a pond plant, but also in the stream, planter or bed. Otherwise, watercress makes no complex demands in terms of care:
- sunny to semi-shady location;
- no direct sunlight;
- Fertilizer is not required;
- only in the bed is compost added;
- weeding in a timely manner;
- regularly check for pests;
- Watercress must always stand in fresh water;
- Pruning after flowering encourages growth.
As part of the cultivation and care of watercress, the hobby gardener should have decided beforehand whether he wants to use it as an ornamental plant or as a vegetable plant. Flowering watercress is no longer suitable for consumption because it then tastes very bitter.
Once you have planted watercress, you can take care of the propagation yourself:
The suitable shoots usually form at the branching of the roots. There they are broken off and placed halfway into a mixture of sand and sifted compost. Of course, the suitable planter should be waterproof and the substrate should be permanently covered with at least 1 cm of water so that the plants root quickly.
If you let the watercress flower, you harvest the seeds in September and in this way always have a supply to sow a new crop. Afterwards, the watercress should be pruned back, even if it is not intended for consumption. If the seeds are kept dry and dark, they will get through the winter well. They can be used for sowing next spring.
In principle, watercress is a hardy plant and can withstand temperatures down to -20° Celsius, but it must not freeze in the water. If they are used as bank planting by the pond, it is advisable to cover them thickly with fleece or to place a wooden board over the plants to prevent them from freezing. In the garden bed, small mounds of earth act as winter protection, over which fleece or foil is spread. Overwintering is much easier if you cultivate the watercress in planters, because you simply bring them into the house. Then the fresh herb will be ready to use in the kitchen all winter long.
diseases and pests
Watercress magically attracts various pests; above all the dreaded slug. Since this voracious pest, like watercress, needs a lot of moisture, it is mainly found on the bank plants and in the garden bed. Therefore, a daily check and the collection of the snails is unavoidable. If the watercress is intended for consumption, no chemical agents such as slug pellets can be used. On the other hand, it is more helpful to attract or settle the natural enemies of the snail. Nudibranchs are the favorite food of Indian runner ducks, hedgehogs and various birds. Ground beetles like to devour the eggs laid in the ground, which are also picked up in no time by free-ranging chickens.
Aphids also do not spare the watercress. To combat them, a mixture of 15 ml of pure soft soap, 1 liter of water and 1 tablespoon of spirit has proven itself as a biological spray. Some hobby gardeners have reported good success in the fight against aphids when using a mixture of half a liter of milk and one liter of water. This is sprayed onto the affected plants for several days in a row.
Standing water not only prevents healthy growth of watercress, but also paves the way for downy mildew. In contrast to powdery mildew, this fungus spreads on the underside of the leaf. The lecithin in the milk mixture can also help here. In addition, a garlic tea can save the watercress. This is made from 2 cloves of garlic, which are poured over with half a liter of boiling water. When the whole thing has cooled down, fill the tea mixture into a squeeze bottle and spray it on the affected plants. Watercress affected by powdery mildew should no longer be consumed.
Small-leaved Watercress Critically Endangered
The ‘little brother’ of the watercress, the small-leaved watercress (Nasturtium microphyllum) also forms delicate, white flowers and prefers similar growing conditions; otherwise this plant has no convincing advantages for the enthusiastic hobby gardener to offer, not even in culinary terms. It is therefore not cultivated and is now on the red list of endangered plant species in some federal states.
Watercress is an amazingly versatile plant that the home gardener can take advantage of according to their individual interests. As a swamp and aquatic plant, watercress adorns a garden or mini pond and a stream with its white flowers. Due to its aromatic taste, the fresh shoots of this plant are often used in the kitchen to refine delicious dishes. Whatever the hobby gardener decides, healthy watercress that grows luxuriantly needs, above all, permanently fresh, preferably calmly flowing, clean water. In addition, the watercress with the botanical name Nasturtium officinale does not require high care. Although it is basically hardy, it should not freeze solid in its water. Thick fleece cloths and foils help against this.