Watercress
Nasturtium officinale
Malay names: Selada Air
Prefers cool, flowing water; can be grown under shade in Malaysia with well-aerated, cool solution.
🌞 Light & Temperature
Light: Bright indirect light to light shade
Temperature: 16–26°C (quality drops >28–30°C)
🪴 Container & Medium
Container: NFT with continuous flow or shallow DWC with strong aeration; shade 50%.
Medium / Solution: Medium: inert supports (foam/clay pebbles); Solution: pH 6.5–7.5, EC 0.8–1.4 mS/cm
💧 Watering / Solution Maintenance
Schedule: Continuous flow preferred; change solution 7–10 days
Top-up: Keep solution cool (20–24°C) and oxygenated
pH 6.5–7.5; EC 0.8–1.4 mS/cm
🧪 Nutrients
Type: Mild leafy nutrient (low EC)
Frequency: Check EC/pH 2–3x/week; change 7–10 days
Dosage/EC: EC 0.8–1.4 mS/cm; pH 6.5–7.5
🍓 Harvest
Start: 4–6 weeks from cuttings
Seasonality: Best in cooler months/shade
Duration: Continuous cuts
Harvest Indicators: Tender shoots 10–15 cm; crisp and peppery
Tips: Harvest often to keep tender; avoid warm, stagnant solution.
🌱 Propagation
Stem cuttings root readily in water.
🐛 Pests & Diseases
- Aphids: Rinse with water; neem 0.5% if needed; increase airflow.
🌦️ Seasonal Notes (Malaysia)
Grow in shade with cool, moving solution; consider chill packs on very hot days.
📝 System Notes
Shallow channels with steady flow work best.
💡 Extra Care Tips
- Keep solution cool and moving
- Harvest frequently to prevent flowering
Note
EC and pH are guidelines—adjust to plant response and your water source. In monsoon humidity, increase airflow and reduce overcrowding to limit disease.