Scientific Name: Nasturtium officinale

Common Name: Watercress

Family: Brassicaceae

Origin

Watercress is a perennial, semi-aquatic, leafy vegetable native across a wide range encompassing parts of Europe and Asia.  Despite belonging to the genus Nasturtium, watercress is unrelated to the garden plant commonly called Nasturtium which actually has the scientific name of Tropaeolum majus.

Culinary Uses

Watercress leaves are flavoursome and piquant, similar to mustard or radish leaves.  Watercress leaves can be cooked in broth to make a simple watercress soup or used in any dish that calls for a green leafy vegetable.  Watercress seeds can be sprouted and eaten as a micro-green.  Watercress is a good source of Vitamins K, C, A, B2 and B6 as well as the minerals Calcium and Manganese.

Other Uses

Watercress produces clusters of small white flowers held above the foliage.  The flowers are a preferred nectar source for the adults stages of many beneficial insect predators, in particular hoverflies.

Growing Tips

Watercress grown in water gardens should be placed in a full sun or lightly shaded aspect.  Watercress stem are hollow and contain air which allows the leaves of the plant to rise above the surface of shallow waters.  Watercress requires a constantly damp soil to survive and should ideally be planted into a pot submerged just below the surface level of a pond, old bathtub or even a large bucket filled with water.  Watercress also grows well in hydroponic grow beds.  They can also be grown successfully out of water if planted in a boggy spot in the garden or into pots filled with a good quality, water-retaining potting mix but they'll require daily waterings.  Watercress grown out of water should be placed in a shady location to prevent them drying out during hot, sunny days.  Watercress grows best when the pH of the water it's submerged into has a neutral to slightly alkaline pH, a range between 7.0 and 7.5 is ideal.  Don't add animal manures to aquatic ponds as doing so can introduce parasites such as liver flukes which can live on the leaves of the watercress and infect humans when they're eaten.  Fertilise your Watercress plants regularly with a complete organic liquid fertiliser, worm juice or compost tea for healthy, vigorous growth. 

When To Sow

In the tropics of Australia you can sow Watercress seeds any time of the year.  In subtropical regions of Australia sow Watercress from September to April.  In temperate regions of Australia sow Watercress from September to March.  In cooler and mountainous regions of Australia sow Watercress seeds during the warmer months from October to February.

How To Sow

Sow Watercress into pots, 5mm deep spacing seed holes about 15cm apart.  Keep constantly moist and transfer the pots into your water garden once the seedlings have a few sets of true leaves. 

Time To Germination

The majority of Watercress seedlings will emerge 6 to 10 days after sowing the seeds.

Time To Harvest

Watercress plants will start producing good quantities of leaves 9 to 10 weeks after sowing the seeds, however you will be able to harvest a few individual leaves before then.  Harvest watercress leaves before the plants begin flowering otherwise they'll taste bitter.  Harvest regularly to promote compact, bushy growth.