Vegetable · Perennial salad green
Watercress
Nasturtium officinaleA cool, water-loving salad green with a peppery bite, traditionally raised in slow-moving streams but easily grown in a constantly wet garden bed or container instead. It craves steady moisture and cool conditions, turning bitter and running to seed the moment things dry out or heat up. The one rule: never let the roots dry out, even for a day.
Sow depth
¼ in
Spacing
6 in · rows 12 in
Sun
Full sun to part shade
Germination
7–14 days
Time to harvest
21–28 days
Difficulty
Moderate
When to sow watercress
- Sow from about 3 weeks before your last expected frost until about 3 weeks after your last expected frost.
- Sow from about 8 weeks before the first expected autumn frost until about 4 weeks before the first expected autumn frost.
Direct sow into a constantly wet bed — a low spot, tub, or pot standing in a water-filled saucer works well.Scatter seed thinly over moist, fertile soil and press in without burying deeply.Keep the seedbed saturated; germination is poor and patchy if it ever dries out.
Never let it dry out — moisture stress turns leaves bitter and triggers bolting.Give afternoon shade and extra water in hot spells; heat above 24°C stresses the plant.Pinch out flower buds and cut often to keep new growth tender.
Snip stems once they reach about 6 in, leaving the crown to resprout.Harvest regularly — frequent cutting keeps leaves mild and delays bolting.Stop picking once flavor turns bitter or flower stalks appear.
Companion plants
Moisture-loving herbs like mint and chives share watercress’s taste for constantly damp soil.
Watch out for
Aphids — Cluster on leaves and stems, causing curling and sooty mold. Rinse off with water or plant lettuce nearby as a trap crop.Slugs and snails — Graze on tender leaves in the same damp conditions the plant needs. Hand-pick at dusk and keep the bed free of plant debris.