Nasturtium officinale

Sowing and cultivation tips

Sow Nasturtium officinale seeds in cool conditions with full sun to light shade. Use a fertile, neutral to slightly alkaline medium kept consistently moist; growth is reliable in shallow water or hydroponic culture. Sow after last frost for spring growth or in late summer to avoid heat; indoors, year-round is possible with ample moisture and bright light. Surface-sow or barely cover and keep moisture steady. Thin early to form low, trailing mats with good air flow, and use clean, fresh water to avoid stagnation. In mild climates, autumn sowing may be possible. Harvesting young growth encourages new shoots; refresh water in containers to maintain oxygenation around roots.

• Maintain a shallow water zone around trays; refresh frequently to prevent stagnation.
• Surface-sow or cover very lightly; keep evenly moist until established.
• Sow thinly; thin seedlings to reduce crowding and improve air flow; follow packet guidance.
• Container-suitable: Performs well in trays, troughs, or hydroponic channels with constant moisture.
• Edible: Grown for tender, peppery shoots and leaves; pick regularly for continued growth.

How do you grow watercress (Nasturtium officinale) from seed?

Sow Nasturtium officinale seeds on the surface of a fertile, moisture-retentive medium and press lightly so they make good contact; barely cover, then mist to keep evenly damp. Provide bright light and cool conditions, avoiding hot, drying spots. Keep the substrate consistently moist by misting or standing trays in a shallow water-filled saucer. Once seedlings are up, thin gradually to create a dense but airy mat; follow packet guidance for final spacing. Plants have a low, trailing habit and appreciate steady moisture and light feeding for leafy growth.

When should I sow watercress seeds after the last frost?

Outdoors, sow after the last frost for spring growth, or wait until late summer to avoid peak heat. In mild climates, autumn sowing may be possible if conditions remain cool and moist. Indoors, watercress can be started year-round provided it receives ample light and constant moisture. As a cool-season crop, it performs best when daytime temperatures are moderate; in hot periods, shift to brighter shade and maintain plentiful water to keep plants from stressing.

What are the best conditions for watercress germination?

For reliable germination, provide cool temperatures, high humidity, and constant moisture without flooding the seed surface. Use a fine-textured, fertile medium and sow thinly so air can circulate. Neutral to slightly alkaline conditions suit watercress; avoid very acidic mixes. Good light supports sturdy seedlings, but intense heat can slow or inhibit sprouting. A clear cover or frequent misting helps maintain surface moisture; bottom-watering via a shallow tray prevents disturbance while keeping the top evenly damp.

Can I grow watercress in containers or indoors?

Yes—watercress is well suited to containers and indoor setups. Choose a wide pot and either use a watertight container or place a draining pot inside a tray that remains topped up with water so the medium stays consistently moist. Provide full sun to light shade; in warm rooms, brighter shade helps prevent stress. Refresh standing water regularly and feed lightly to maintain steady growth. Indoors, supplemental lighting keeps plants compact and productive, and regular thinning preserves airflow over dense mats.

Can watercress grow in shallow water or be started hydroponically from seed?

Watercress thrives at the edge of shallow, clean water and adapts well to hydroponics. For shallow-water culture, keep crowns above the waterline with stems and roots in a few centimetres of fresh water, replacing or circulating it to prevent stagnation. For hydroponics, start seeds on inert cubes or mesh, then move seedlings to a gentle-flow or raft system. Maintain a mild nutrient solution and a pH around neutral to slightly alkaline, with bright light and cool conditions for leafy, continuous growth.

How much sun and what soil pH does watercress need, and how do I harvest cut-and-come-again?

Watercress grows best in full sun to light shade; in hot spells, provide shade to keep plants cool and tender. It prefers neutral to slightly alkaline conditions in a fertile, consistently moist medium. Harvest as a cut-and-come-again green by snipping young stems above the crown, leaving nodes to reshoot; take modest cuts regularly rather than stripping plants at once. Frequent harvesting encourages branching and tender regrowth, especially when moisture, light, and airflow are kept steady.

Growing information presented here is general, compiled from standard horticultural sources and practical experience. Conditions differ by microclimate, soil structure, drainage, and seasonal patterns. Timing cues—after last frost, when soil is workable, or, in mild climates, autumn sowing—should be adapted to local conditions. Product pages provide variety-specific details, including spacing, sowing depth, and timing, and contain the most current instructions for each item.

Cultivation guidance for water-loving plants

Nasturtium officinale seeds suit cool, consistently moist setups. Sow after last frost when soil is workable; in mild climates, autumn sowing may be possible. Press seeds onto the surface of fine, damp compost and barely cover, as light helps germination. Keep humidity high and temperatures on the cool side; steady moisture is essential. Seedlings can be grown in trays or containers stood in shallow, clean water, or in rich soil kept constantly wet near pond edges. Provide dappled shade in heat, or brighter light where summers are mild. Space plants to allow airflow and quick regrowth, trimming regularly to keep growth tender. Avoid stagnant conditions; refresh water and rinse containers as needed. For a continuous display, stagger small sowings every few weeks during the cool season. Nasturtium officinale appreciates neutral to slightly alkaline conditions and benefits from a gentle, balanced feeding if growth slows. Further information and seed ranges are available at SeedsChoice.