Growing watercress; green goodness
Whether you treat it like a herb or a vegetable, growing watercress is rewarding for the home gardener. In the cities you’re likely to find a reliable if costly supply, but I haven’t seen it for sale out here, and it’s very handy to have to pick at anytime for a garnish, or to liven up a sandwich, or on the larger scale to use as the main vegetable in a soup or frittata. A problem with bought watercress is that it tends to be all stem with yellow leaves low down, and picking out the leaves can be tedious. Growing watercress in your own garden, you can pick short stems with lots of leaves that go straight into the pot.
Watercress will grow in a normal vegetable bed if you keep it moist, but I thought I’d take advantage of a couple of drainage ditches in the garden. The first is an overflow channel from the house rainwater tanks, on a difficult patch of clay. It runs with water whenever it rains, and on dry days I empty my vegetable washing water into it. The second ditch is combined drainage and access to the reticulation pipe in the Midlevels garden, which stays nicely wet too.
I started mine from seed bought from a local provider. Watercress germinates readily in standard seed trays and then is easy to transplant into the garden. I just lifted out plugs of many seedlings, as I had sowed it thickly.
Winter is a good time to sow watercress in subtropical climates like ours.
Watercress likes a neutral to alkaline pH, so I dressed the bottom of both trenches with lots of lime. I doubt you could over-do the liming, as apparently commercial watercress farms are often on streams that come directly from limestone or chalk. The advantage in my gardens is that any outflow from the trenches which has picked up dissolved calcium runs on to vegetable beds which need plenty of liming anyway. I also used some coco-peat to give a neutral and spongy support.
A word about the wetness; watercress grows naturally in clean flowing water, so it is probably better to keep it moist in an ordinary garden bed than to try it in stagnant water. The roots need aeration, and you’ll find they form a dense white mat above ground level, hence the need to keep it moist on dry days.
Land cress – an alternative that’s also good for caterpillar control
There are other cresses, and I have a great crop of land cress but the flavour is very strong. I’m growing it mainly on Jerry Coleby Willams’ recommendation, as a decoy plant for cabbage white butterflies, and seems to be working for that. Apparently the butterflies are attracted to lay their eggs on the cress rather than your crop brassicas, and then the caterpillars die. I got the seeds from a local supplier, just like the watercress, and started them in a seed tray. They officially like moist soil, although not as wet as watercress, but mine do fine in quite dry conditions and full sun. Possibly if I took more care of them they would be more succulent and less pungent.
But if you’ve got a spot that might work, why not try both?
In the kitchen
When I was growing up watercress grew wild in the drainage ditches in the parkland across the Swan River from Perth city, which were just across the road from our house. As I had read to be cautious of wild-picked watercress (disease causing organisms can lurk in the water) I picked then boiled the hell out of a big bunch to make soup. This has remained one of my favourite soups, as the flavour is unique. If you’re sure of your supply, or grow your own, you can reserve a good bunch of leaves for throwing in after the soup has cooked. Just puree it with a hand blender and you get the fresh green colour as well as the taste.
Watercress is beautiful in salads and lots of other cooked dishes, besides being a pretty garnish, so get creative and think about converting that wet drainage channel to a productive bed.