When to plant Watercress in Temperate Australia

Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.

Sow watercress direct from August to November in spring, or in the cooler February to April autumn window, scattering seed just 3 mm deep on constantly wet ground. Seed germinates quickly in 7–14 days, and you can start cutting in 50–70 days. Thin plants to 15–20 cm apart with rows around 25–30 cm, though watercress spreads readily once it takes. It is fully hardy, so it shrugs off frost in Melbourne and Canberra-fringe gardens, and does best in the cooler, wetter halves of the year across temperate Australia.

Sowing calendar — temperate zone

Green months are your sowing window: February to April and August to November.

Growing notes

Watercress lives or dies by water. It needs its roots permanently wet, so grow it in a shallow, shaded pot standing in a tray of water, at the muddy edge of a pond, or in a bed you flood daily. In an Adelaide or Perth summer it will bolt and turn bitter fast, which is why the cooler months are the sweet spot for tender growth.

The most common failure is letting it dry out even once. A single day of dry roots checks growth and the leaves toughen. Keep the water fresh rather than stagnant, refreshing the tray every few days to discourage mosquito larvae and algae.

Heat is the other enemy. As spring warms, watercress rushes to flower and the flavour turns harsh. Cut regularly to delay bolting, move pots into shade, and treat late spring plantings as short-lived. Aphids sometimes gather on stressed plants; a firm hose-off usually clears them, and healthy, well-watered plants rarely suffer. Cuttings root in water within days, so once you have one plant you need never buy seed again.

Watercress at a glance

Common questions

how to grow watercress without a stream

Grow it in a pot standing permanently in a tray of water, topped up daily, or at the wet margin of a pond. The key is roots that never dry out. Refresh the tray water every few days to keep it from going stagnant.

when to plant watercress in Melbourne

Sow in the spring window of August to November, or again in autumn from February to April, avoiding the peak of summer heat. Watercress is hardy and handles Melbourne's cool season easily. Cooler months give sweeter, less bitter leaves.

why is my watercress bitter

Bitterness comes from heat and from the plant bolting to flower as temperatures rise. Keep it cool and shaded, cut regularly, and grow it mainly in the cooler halves of the year. Consistent water also keeps the flavour mild.

can you grow watercress from cuttings

Yes, easily. Pop a few stems from bought watercress into a glass of water and they will root within days, ready to plant into wet soil. It is often faster than starting from seed.

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