Lettuce)
Lactuca sativa
Malay names: Selada, Salad
Heat-tolerant looseleaf/romaine types suited to Malaysian balconies under light shade with good airflow.
🌞 Light & Temperature
Light: Bright light to partial sun (4–6 h) with 30–50% shade net in heat
Temperature: 18–28°C (quality declines >32°C)
🪴 Container & Medium
Container: NFT/DWC/raft; 2–3 inch net pots with clay pebbles or coco plugs; 15–30 L reservoir per 6–10 plants.
Medium / Solution: Medium: clay pebbles/rockwool/coco plugs; Solution: pH 5.8–6.2, EC 1.2–1.8 mS/cm
💧 Watering / Solution Maintenance
Schedule: Top-up daily to maintain level; full solution change every 10–14 days
Top-up: Top-up with plain water to target EC; add nutrients as needed
Target pH 5.8–6.2; EC 1.2–1.8 mS/cm after seedling stage (0.8–1.2 for seedlings). Keep reservoir 20–24°C if possible.
🧪 Nutrients
Type: Complete hydroponic A+B nutrient with Ca/Mg and micronutrients
Frequency: Check EC/pH 2–3x/week; adjust; full change every 10–14 days
Dosage/EC: Mix per label to EC 1.2–1.8 mS/cm (seedlings 0.8–1.2); maintain pH 5.8–6.2
🍓 Harvest
Start: 3–5 weeks from transplant
Seasonality: Best in drier months or under shade/airflow
Duration: Cut-and-come-again harvest for 2–4 weeks
Harvest Indicators: Loose leaves 12–20 cm; romaine heads firming; crisp texture
Tips: Harvest mornings for best crunch; avoid water on leaves late evening to reduce disease.
🌱 Propagation
Seeds; transplant at 2–3 true leaves.
🐛 Pests & Diseases
- Aphids/whiteflies: Yellow sticky traps; neem oil 0.5–1% weekly; release lacewings if available.
- Downy mildew/leaf spots: Improve airflow; avoid leaf wetting at night; copper in severe cases.
- Algae in channels: Block light to solution; clean biofilm during changes.
🌦️ Seasonal Notes (Malaysia)
Use shade net and fans during monsoon humidity; choose heat-tolerant cultivars (e.g., Green Cos).
📝 System Notes
Keep crown above net pot rim; space 20–30 cm; sanitize tools and channels.
💡 Extra Care Tips
- Stagger sowing every 1–2 weeks for continuous harvest
- Keep reservoir shaded and aerated
- Flush with plain water between batches
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.