Watercress

An excellent base for interesting salads and very high in nutrition, watercress is always at its best when freshly picked straight from the garden. 

This interesting plant is a brassica, so is related to mustard and cabbage. Watercress is a leafy aquatic plant that’s found its way onto our tables in watercress sandwiches, in fancy salads and as a garnish. It is also a delicious sprout. Watercress is nutritious but has a very short self-life: two good reasons to grow your own.

A recent study from the US Center for Disease Control named it the most nutritious vegetable to eat. Analysis shows it is a good source of iron, is rich in folic acid and also contains high amounts of calcium, protein, fibre and vitamins. One of its constituents — gluconasturtiin — may even inhibit carcinogens.

This is a plant of many faces — I’ve even seen it growing in streams and creeks in Australia where it’s technically an aquatic weed. Its hollow stems allow it to float on the water surface. Left to its own devices it forms a tangle of long stems.

The leaves are sweet and slightly peppery when young but have a “bite” once the plant begins to flower.

Watercress harvested from streams or creeks should be well washed and consumed only if from clean, fresh water. It can harbour the liver fluke parasite, so never harvest it from areas where there’s manure nearby (for example, from grazing sheep, cattle or horses) or if it is growing in stagnant water.

Growing tips

Although watercress must be kept moist, you don’t need a fast-flowing stream on hand. Sow seeds in a pot of moist potting mix, which can be kept damp by standing it in a tray or bucket of water. Use a good quality organic potting mix and stand the pot in sun or part shade.
Feed occasionally using an organic liquid plant food. Change the standing water frequently so it stays fresh and free of mosquito larvae. Seeds take around eight to 12 days to germinate and need around two months to grow to a size that’s large enough to harvest. If watercress is needed more quickly it can be grown from stems of organic watercress. Seeds can also be sprouted in trays and harvested when they are about 5cm high.