Climate matters. This page is a practical baseline. Confirm cultivar, local frost/heat conditions, mature size and regional restrictions before planting.
Watercress — Growing reference
| Scientific name | Nasturtium officinale |
|---|---|
| Seed germination (days) | 7–14 |
| Soil temperature for germination (°C) | 10–20 |
| First harvest or flowering (days) | 50–70 |
| Measured from | Seed |
| Plant spacing (cm) | 15.2–20.3 |
| Mature height (cm) | 10.2–25.4 |
| Mature spread (cm) | 20.3–30.5 |
| USDA hardiness zones | 3–11 |
| Light | Partial sun |
| Water | High |
| Sowing method | Direct sow |
Growing directions
Sow seed on the surface of consistently moist, fertile soil near a stream, pond edge, or other reliably wet site; watercress requires more water than almost any other salad green. In garden beds without standing water, water deeply every day and mulch heavily to retain moisture. Harvest stem tips of 4–6 in regularly to encourage bushy growth; the plant becomes bitter and coarse after flowering. Succession plantings from rooted stem cuttings placed in shallow water provide a continuous supply through the cool season.
Source and local conditions
Typical planning ranges from OpenPlantDB (CC0). Cultivar, climate, season and growing method can change these values. Confirm the seed label and local guidance before planting.
Source & verification
OpenPlantDB · CC0