Nasturtium officinale Care Guide
Nasturtium officinale (watercress) is an edible aquatic leaf vegetable used in paludariums and stream biotopes, thriving in cool, well-oxygenated flowing water.
Compiled by Aquairi from published sources · Published · Updated
Overview
Nasturtium officinale, watercress, is an aquatic herb and leaf vegetable of the family Brassicaceae. It has hollow stems that float in water, pinnately compound leaves, and small white-and-green flower clusters, and can reach up to about 60 cm in length. It is one of the oldest known leaf vegetables consumed by humans.
Taxonomy
- Family: Brassicaceae
- Genus: Nasturtium
- Scientific name: Nasturtium officinale
- Order: Brassicales
Habitat
The species is native to Eurasia and is now cultivated across temperate regions worldwide. Clear, fast-flowing chalk streams are its primary natural habitat in the UK; it favours alkaline water and is well suited to flowing, cool conditions.
Tank requirements
- Water type: freshwater (emergent / stream)
- Temperature: 10-22 °C (50-72 °F)
- pH: 6.0-8.0
- GH: 4-18 °dGH
- Lighting: medium
- CO2 injection: not required
- Placement: background; height up to ~30 cm
Growth and propagation
Watercress is fast-growing and is best kept emergent in paludariums and stream-style biotopes with cool, well-oxygenated, flowing water. It is propagated easily from cuttings. Frequent trimming, roughly every two weeks, both harvests edible growth and keeps the planting tidy.
Uses
Leaves, stems and fruit are edible raw or cooked, and the plant is notably high in vitamins K and C. Its preference for clean, running water makes it a fitting choice for cool stream biotope displays.
Propagating Watercress (Nasturtium officinale) from Stem Cuttings
Overview
Nasturtium officinale, watercress, is a rapidly growing aquatic perennial of the cabbage family, native to Eurasia. Its hollow stems float in water, and it carries pinnately compound leaves. Its prime natural habitat is clear, fast-flowing, cool chalk streams. Leaves, stems and fruit can be eaten raw, making it a favourite edible plant for stream-style biotopes and paludariums.
Propagation Method
Watercress propagates extremely easily from stem cuttings, which root readily at their nodes. Established clumps can also be lifted and divided. Because the plant grows fast, a single trimming session can yield many new plants.
Step-by-Step
- Cut a healthy stem section, 8–15 cm long, that includes at least one or two nodes.
- Place the cutting in shallow, cool, flowing or frequently refreshed water.
- Within days, fine roots emerge from the submerged nodes.
- Once rooted, anchor the cutting in substrate at the waterline, or let it float.
- For division, separate a rooted clump and replant the pieces with their crowns wet.
Conditions for Healthy Growth
Watercress wants cool water, roughly 10–22 degrees C, with good oxygenation from flow and a pH of about 6–8 (it tolerates and even prefers slightly alkaline conditions). Medium light suits it. Cool, clean, moving water is the single biggest factor in lush growth.
Maintenance
Harvest and trim regularly to keep the planting young and productive; the cut stems double as cuttings for the next batch. Refresh or keep water moving to maintain oxygen and to mimic its stream habitat.
Common Challenges
Warm, stagnant water is the main enemy — it stresses the plant and invites rot. Note too that watercress is invasive in some regions (it is prohibited in Illinois, for example), so never release it into natural waterways and dispose of trimmings responsibly.